CN111581798B - Method and device for evaluating the remaining life of a support leg - Google Patents
Method and device for evaluating the remaining life of a support leg Download PDFInfo
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Abstract
The embodiment of the invention provides a method and a device for evaluating the residual life of a supporting leg, belonging to the field of engineering machinery. The method comprises the following steps: determining the stress of a supporting point of the supporting leg; calculating the stress change rate of the supporting point of the supporting leg; evaluating abnormal life loss at the stress analysis point according to the stress of the supporting leg supporting point and the change rate of the stress of the supporting leg supporting point; and assessing the remaining life of the leg based on the abnormal life loss at one or more of the stress analysis points. The method is beneficial to guiding a user to reasonably use the engineering machinery, and property loss or construction accidents caused by damage of the supporting leg structure are avoided.
Description
Technical Field
The invention relates to the field of engineering machinery, in particular to a method and a device for evaluating the residual life of a support leg.
Background
The movable engineering machinery with tipping risk during operation adopts a mode of unfolding 'supporting legs' on a construction site to enhance the tipping prevention capacity of equipment, and the engineering machinery such as a concrete pump truck, a fire truck, a crane, an all-terrain crane, a bridge detector, an aerial work platform, aerial cleaning equipment and the like.
The legs therefore have a "foot" lifting effect on the anti-tipping safety of the device. The strength loss or structural defects of the support legs caused by abnormal stress, fatigue aggravation and the like seriously threaten the use safety and the service life of the engineering machinery.
Disclosure of Invention
It is an object of embodiments of the present invention to provide a method and apparatus for assessing the remaining life of a leg, which can provide an efficient assessment of the remaining life of the leg.
In order to achieve the above object, an embodiment of the present invention provides a method for evaluating a remaining life of a leg, the method including: determining the stress of a supporting point of the supporting leg; calculating the stress change rate of the supporting point of the supporting leg; evaluating abnormal life loss at the stress analysis point according to the stress of the supporting leg supporting point and the change rate of the stress of the supporting leg supporting point; and assessing the remaining life of the leg based on the abnormal life loss at one or more of the stress analysis points.
Optionally, the evaluating the current stress versus the life loss at the stress analysis point includes calculating an abnormal life loss at the stress analysis point according to the following formula:
i k (t)＝G k (f(t),w(t))，
wherein i k (t) is the abnormal life loss at the stress analysis point, f (t) is the stress of the supporting leg supporting point, w (t) is the change rate of the stress of the supporting leg supporting point, k is the number of the stress analysis point, t is time, G k () Is a functional relationship having an integrating or convolution effect on said f (t) and w (t), wherein said G k () And f (t) and w (t) are positively correlated.
Optionally, the abnormal life loss at the stress analysis point is calculated according to the following formula:
fk1 is a first stress threshold, fk2 is a second stress threshold, fk2 is larger than or equal to Fk1, wk1 is a first stress disturbance quantity threshold, wk2 is a second stress disturbance quantity threshold, wk2 is larger than or equal to Wk1, wherein Fk1 and Fk2 are obtained according to the maximum allowable stress at the stress analysis point, and Wk1 and Wk2 are obtained according to the maximum allowable stress disturbance quantity at the stress analysis point.
Optionally, the estimating the remaining life of the leg based on the abnormal life loss at the one or more stress analysis points comprises calculating the remaining life of the leg according to the following formula:
wherein I (T) is the residual life of the landing leg, T0 is the design life of the landing leg without abnormal use, I k (t) is the abnormal life loss at the stress analysis point, a is a correction coefficient, k is the number of the stress analysis point, n is the number of the stress analysis points, b is the leg life wear coefficient, t is time, and ^ bdt represents the life loss due to the time that the leg has been used.
Optionally, the determining the stress of the supporting point of the supporting leg includes: detecting first hydraulic oil pressure in a rod cavity of a supporting leg oil cylinder and second hydraulic oil pressure in a rodless cavity of the supporting leg oil cylinder; and calculating the stress of the supporting point of the supporting leg according to the following formula:
f(t)＝S1*p1(t)-S0*p0(t)，
f (t) is stress of the supporting point of the supporting leg, S1 is the volume sectional area of a rod cavity of the supporting leg oil cylinder, p1 (t) is the pressure of the first hydraulic oil, S2 is the volume sectional area of a rodless cavity of the supporting leg oil cylinder, and p0 (t) is the pressure of the second hydraulic oil.
Optionally, the method further includes: calculating the residual life change rate of the supporting leg; and when the remaining life change rate exceeds the threshold range, sending out a prompt.
Correspondingly, the embodiment of the invention also provides a device for evaluating the residual life of the supporting leg, which comprises: the determining module is used for determining the stress of the supporting point of the supporting leg; the first calculation module is used for calculating the stress change rate of the supporting point of the supporting leg; the first evaluation module is used for evaluating the abnormal life loss at the stress analysis point according to the stress of the supporting leg supporting point and the change rate of the stress of the supporting leg supporting point; and a second evaluation module for evaluating the remaining life of the leg based on abnormal life loss at one or more of the stress analysis points.
Optionally, the first evaluation module calculates the abnormal life loss at the stress analysis point according to the following formula:
i k (t)＝G k (f(t),w(t))，
wherein i k (t) is the abnormal life loss at the stress analysis point, f (t) is the stress of the supporting leg supporting point, w (t) is the change rate of the stress of the supporting leg supporting point, k is the number of the stress analysis point, t is time, G k () Is a functional relationship having an integrating or convolution effect on said f (t) and w (t), wherein said G k () And f (t) and w (t) are positively correlated.
Optionally, the first evaluation module calculates the abnormal life loss at the stress analysis point according to the following formula:
fk1 is a first stress threshold, fk2 is a second stress threshold, fk2 is larger than or equal to Fk1, wk1 is a first stress disturbance quantity threshold, wk2 is a second stress disturbance quantity threshold, wk2 is larger than or equal to Wk1, wherein Fk1 and Fk2 are obtained according to the maximum allowable stress at the stress analysis point, and Wk1 and Wk2 are obtained according to the maximum allowable stress disturbance quantity at the stress analysis point.
Optionally, the second evaluation module calculates the remaining life of the leg according to the following formula:
wherein I (T) is the residual life of the support leg, and T0 is the no-abnormity state of the support legDesign life in use, i k (t) is the abnormal life loss at the stress analysis point, a is a correction coefficient, k is the number of the stress analysis point, n is the number of the stress analysis points, b is the leg life wear coefficient, t is time, and ^ bdt represents the life loss due to the time that the leg has been used.
Optionally, the determining module determines the stress of the supporting point of the supporting leg according to the following steps: detecting first hydraulic oil pressure in a rod cavity of a supporting leg oil cylinder and second hydraulic oil pressure in a rodless cavity of the supporting leg oil cylinder; and calculating the stress of the supporting point of the supporting leg according to the following formula:
f(t)＝S1*p1(t)-S0*p0(t)，
f (t) is stress of the supporting point of the supporting leg, S1 is the volume sectional area of a rod cavity of the supporting leg oil cylinder, p1 (t) is the pressure of the first hydraulic oil, S2 is the volume sectional area of a rodless cavity of the supporting leg oil cylinder, and p0 (t) is the pressure of the second hydraulic oil.
Optionally, the apparatus further comprises: the second calculation module is used for calculating the residual life change rate of the supporting leg; and the prompting module is used for sending out a prompt when the change rate of the remaining service life exceeds the threshold range.
Accordingly, the embodiment of the present invention further provides a machine-readable storage medium, on which instructions are stored, and the instructions are used for causing a machine to execute the method for evaluating the remaining life of the leg.
Through the technical scheme, the abnormal service life loss at the stress analysis point is firstly evaluated according to the stress of the supporting leg supporting point and the change rate of the stress of the supporting leg supporting point, and then the residual service life of the supporting leg is evaluated based on the abnormal service life loss at one or more stress analysis points of the supporting leg, so that the reasonable use of engineering machinery by a user is facilitated, and property loss or construction accidents caused by the damage of the supporting leg structure are avoided.
Additional features and advantages of embodiments of the invention will be set forth in the detailed description which follows.
Drawings
The accompanying drawings, which are included to provide a further understanding of the embodiments of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the embodiments of the invention and not to limit the embodiments of the invention. In the drawings:
FIG. 1 shows a schematic flow diagram of a method for assessing the remaining life of a leg according to an embodiment of the invention;
FIG. 2 is a diagram illustrating selection of stress analysis points in one embodiment; and
fig. 3 shows a block diagram of an apparatus for evaluating the remaining life of a leg according to an embodiment of the present invention.
Detailed Description
The following detailed description of embodiments of the invention refers to the accompanying drawings. It should be understood that the detailed description and specific examples, while indicating embodiments of the invention, are given by way of illustration and explanation only, not limitation.
The stress structure of the landing leg of the engineering machinery is basically a typical 'cantilever structure', and the stress of the landing leg is also the concentrated stress of a simple determined point (supporting sole, also called as landing leg supporting point) and a determined direction (vertical upward), so that the stress (stress) of each part of the landing leg and the stress value of the landing leg supporting point have different one-to-one correspondence relations, namely, a mapping or functional relation exists, and therefore, different stresses of different parts of the landing leg can be calculated or searched out through stress detection of the landing leg supporting point. Therefore, the condition of abnormal service life loss of the supporting leg can be further judged, and service life estimation can be carried out.
Fig. 1 shows a flow diagram of a method for evaluating an abnormal life loss of a leg according to an embodiment of the invention. As shown in fig. 1, an embodiment of the present invention provides a method for evaluating an abnormal life loss of a leg, which may be performed by a controller of a working machine, and may include steps S110 to S140.
In step S110, the force of the leg support point is determined.
Specifically, the pressure sensors installed on the vertical oil path of the support leg may be used to detect a first hydraulic oil pressure p1 (t) in the rod chamber of the support leg oil cylinder and a second hydraulic oil pressure p0 (t) in the rodless chamber of the support leg oil cylinder. The volume sectional area of a rod cavity of the supporting leg oil cylinder is recorded as S1, and the volume sectional area of a rodless cavity of the supporting leg oil cylinder is recorded as S2, so that the stress f (t) of a supporting point of the supporting leg can be calculated according to the following formula:
f(t)＝S1*p1(t)-S0*p0(t) (1)
where t represents time, which may be the current time. The first hydraulic oil pressure p1 (t) and the second hydraulic oil pressure p0 (t) can be detected in real time, the volume sectional area S1 of the rod cavity and the volume sectional area S2 of the rodless cavity can be known in advance, and the stress of the supporting point of the supporting leg can be calculated in real time.
The pressure sensors arranged on the oil passages of the oil cylinders are used for detecting the pressure of hydraulic oil in the rod cavities and the rodless cavities, so that the detection reliability can be greatly enhanced, and the continuous monitoring capability can be correspondingly enhanced.
It is to be understood that the embodiments of the present invention are not limited to determining the force of the supporting point of the leg by using the formula (1), for example, the pressure of the supporting point of the leg may be detected by installing a counterforce sensor at the supporting point of the leg, wherein the counterforce sensor is an integrated sensor that detects the force value transmitted by the contact surface by means of surface contact. In addition, stress of supporting points of the supporting legs can be measured by adopting a strain gauge, a weighing sensor, a pin shaft force measuring sensor and the like, wherein the two types of the weighing sensor and the pin shaft force measuring sensor are used for detecting stress by means of deformation of the elastic body, but the integrated characteristic of the two types of the strain gauges is higher in reliability and consistency compared with the strain gauge.
In step S120, a rate of change of the force applied to the supporting point of the leg is calculated.
When the engineering machinery works, the stress of the engineering machinery is not static, but changes at any time along with the working condition of the mechanical working part, and the reaction on the supporting leg is a dynamic process of stress of each part of the supporting leg. Practice proves that the dynamic change process of stress of each part of the supporting leg is just an important factor causing the fatigue of the supporting leg material and influencing the service life of the supporting leg, and the stress of each part has a corresponding relation with the stress of the supporting point of the supporting leg, so that the detection of the dynamic change of the stress of the supporting point of the supporting leg is also an important aspect for monitoring the abnormal loss of the supporting leg.
Specifically, the rate of change w (t) of the stress of the supporting point of the leg can be calculated according to the following formula:
wherein t is the current time, t 1 F (t) is the stress of the supporting point of the supporting leg at the previous moment, and f (t) is the stress of the supporting point of the supporting leg at the current moment 1 ) The stress of the supporting point of the supporting leg at the previous moment.
In step S130, the abnormal life loss at the stress analysis point is evaluated according to the stress of the leg support point and the rate of change of the stress of the leg support point.
The stress analysis point may be any point selected from the leg, for example, it may be a point within the focal area of the leg, which may be an area judged to be weak when the leg is designed. Since the probability of abnormal life loss of the vertical leg is small, it is preferable to select a stress analysis point on the horizontal leg to evaluate the abnormal life loss of the horizontal leg.
Optionally, the abnormal life loss estimation function of any stress analysis point of the leg may be established as follows:
i k (t)＝G k (f(t),w(t)) (3)
wherein i k (t) is the abnormal life loss at the stress analysis point, f (t) is the stress of the supporting leg supporting point, w (t) is the change rate of the stress of the supporting leg supporting point, k is the number of the stress analysis point, t is time, G k () Is a functional relationship having an integrating or convolution effect on said f (t) and w (t), wherein said G k () Is in positive correlation with f (t) and w (t), i.e. when a force-bearing abnormal event occurs, f (t) or w (t) has a positive reaction, i k (t) a positive determination or accumulation is obtained such that the resulting residual life estimate of the leg is reduced.
Here, G will be exemplified in a quantized manner k () The function may be specifically as follows:
fk1 is a first stress threshold, fk2 is a second stress threshold, fk2 is larger than or equal to Fk1, wk1 is a first stress disturbance quantity threshold, wk2 is a second stress disturbance quantity threshold, wk2 is larger than or equal to Wk1, wherein Fk1 and Fk2 are obtained according to the maximum allowable stress at the stress analysis point, and Wk1 and Wk2 are obtained according to the maximum allowable stress disturbance quantity at the stress analysis point.
The maximum allowable stress and the maximum allowable stress disturbance amount at different stress analysis points are different. The maximum allowable stress can be obtained by means of experimental tests, for example, by attaching a strain gauge to the stress analysis point of the leg. The stress disturbance amount refers to the amplitude of the cyclic stress, and the maximum stress disturbance amount refers to the maximum amplitude of the cyclic stress. In addition, the data can also be obtained through simulation by structural design analysis software, which typically can be ANSYS (finite element analysis), ABAQUS, MSC, NX nanostran, ALGOR, and the like.
The second stress threshold Fk2 may be 90% of the maximum allowable stress Fkmax at the stress analysis point, and the first stress threshold Fk1 may be 80% of the maximum allowable stress Fkmax at the stress analysis point. The second stress disturbance amount threshold Wk2 may be 90% of the maximum allowable stress disturbance amount Wkmax at the stress analysis point, and the first stress disturbance amount threshold Wk1 may be 80% of the maximum allowable stress disturbance amount Wkmax at the stress analysis point. It is to be understood that the above percentages are for example only and embodiments of the invention are not limited thereto. In addition, other suitable manners for determining the thresholds may also be used.
G k () The function is not limited to the specific example shown in formula (4), and G is constructed in a discrete quantization manner as in formula (4) k () In the case of a function, other index indices of division may be used to calculate i k (t) divided into a plurality of classes, 2, 4, etc., and given different values, e.g. into 4 classes, i k The (t) value range can be (5, 3,1, 0), (7, 4,2, 1), etc.
It is noted that the construction machine has a large number of telescopic leg structures in addition to the legs having a deterministic connection structure, such as four legs of a pump truck, in which the local stress of the legs is influenced by the real-time posture of the legs, i.e., the elongation of the legs, in addition to the external force of the supporting points of the legs. Therefore, in the formula (3), the influence of the horizontal elongation of the leg needs to be considered, and the formula (3) can be modified as follows:
i k (t)＝G k (f(t),w(t),l(t)) (5)
wherein l (t) represents the horizontal elongation of the leg.
Accordingly, equation (4) can be modified as:
the expression of equation (6) after the brace is unchanged from equation (4), in fact because f (t) of the stress analysis point has been changed for different leg lengths l (t). Therefore, in actual implementation, equation (4) may be used to evaluate the abnormal life loss at the stress analysis point. On the other hand, the above situation also indicates that the calculation method disclosed by the embodiment of the invention has robustness, and the same algorithm can be adopted for different leg postures, which facilitates consistent and accurate expression and estimation of abnormal life loss of the legs under different postures.
In step S140, the remaining life of the leg is evaluated based on the abnormal life loss at one or more of the stress analysis points.
The remaining life of the leg may be derived from statistics of abnormal life losses at one or more stress analysis points of the leg. The number of stress analysis points selected on the support leg can be any specified value, the area where the stress analysis points are located is not limited to the focus area and can be any area, and in addition, the distribution of the stress analysis points selected in the area can not have uniformity, consistency or other limiting characteristics.
Alternatively, the remaining life of the leg may be calculated according to the following formula:
wherein I (T) is the residual life of the support leg, T0 is the design life of the support leg when the support leg is not used abnormally, I k (t) is the abnormal life loss at the stress analysis point, k is the number of the stress analysis points, n is the number of the stress analysis points, b is the life wear coefficient of the leg, t is the time, and: [ integral ] bdt represents the life loss due to the time the leg has been used. b is a known value and can be provided by the manufacturer of the legs. a is a correction coefficient, which can function as a weighting coefficient for correcting different numbers of statistical proportions and converting the dimension into a dimension consistent with T0. a can be obtained in advance by experiments.
The remaining life of the leg is not limited to the formula (7), and other statistical methods may be used to obtain the remaining life of the leg, such as a mean statistical method. In an extensible embodiment, separate exceptional life loss functions may be established for any location of the legs (e.g., different focal zones) to determine remaining life for different locations; a plurality of residual life functions can be set for one supporting leg, and the calculated values of the residual life functions are counted to obtain the residual life of the supporting leg; or an integral residual life function is set for the supporting leg, so that the application is very flexible.
In the formula (7), n is a natural number greater than or equal to 1. When n =1, it means that the abnormal life loss of the region or the leg is evaluated with only one stress analysis point.
Preferably, n is a natural number greater than 1, which has the advantage that: (1) Stress abnormal events related to fatigue or impact in the region can be covered more fully; (2) By utilizing the comprehensive evaluation of multiple data, the misjudgment can be eliminated, and the accuracy of abnormal event judgment is enhanced; (3) The value of n is consistent with the analysis process or the experimental test process, and the value of the surface n is not completely subjective.
Fig. 2 shows a schematic diagram of the selection of stress analysis points in an embodiment. Fig. 2 shows the selection of two areas on the horizontal leg, where n =24 stress analysis points are selected in one area and n =12 stress analysis points are selected in the other area. However, it is understood that the value of n is not limited thereto. The stress analysis points may be in any arbitrarily segmented selected region of the horizontal leg. The number of stress analysis points selected on the legs can be any specified value, the selected area can be any area, and the distribution of the selected stress analysis points in the area can have no uniformity, consistency or other limiting characteristics.
For example, the design life T0 is 10 years, the design life has been used for 3 years, the operating rate is 50%, b is 1.2, and a is 0.008 years. The third term of the formula (9) is 1.2 x 3 x 0.5=1.8 years, the second term carries out analog sampling on 10 stress analysis points, and 1 type of events (i) are recorded k (t) event with value 1) 100 events, class 2 event (i) k Events with a value of 0.5 for (t) 300 times, then the value of a (100 +300 0.5) =2 according to the calculation of the second term, i.e. these events produce an abnormal loss of life for 2 years. In the above case, although it is used for 3 years, the loss life is 1.8+2=3.8 years, because it has too many abnormal use events, the remaining life is 10-3.8=6.2 years.
The abnormal service life loss of the stress analysis point is evaluated according to the stress of the supporting point of the supporting leg and the change rate of the stress of the supporting point of the supporting leg, then the residual service life of the supporting leg is evaluated based on the abnormal service life loss of one or more stress analysis points of the supporting leg, an effective data base is provided for monitoring the use condition of the supporting leg, and therefore the reasonable use of engineering machinery by a user is facilitated, and property loss or construction accidents caused by the structural damage of the supporting leg are avoided.
Further, the method for evaluating the remaining life of the leg provided by the embodiment of the invention may further include: calculating the residual life change rate of the supporting leg; and when the remaining life change rate exceeds the threshold range, sending out a prompt.
The remaining life change rate I' (t) of the leg can be calculated according to the following formula:
wherein t is the current time, t 1 At the previous moment, I (t) is the remaining life of the leg at the current moment, I (t) 1 ) The remaining life of the leg at the previous time.
The threshold range may be defined by, for example, a threshold In, I' (t) being greater than the threshold In, indicating that the event currently being performed by the work machine is a dangerous event, and the controller may issue, for example, an alarm prompt to alert the user. The threshold In may also be scalable, as it may be divided into a plurality of levels, with different levels corresponding to different degrees of dangerous events.
The controller of the work machine may send the estimated abnormal life loss, remaining life, and/or dangerous event prompt (if any) to the data platform in a wireless or wired communication manner, and the data platform may send the data to the client in a wireless or wired communication manner, so that the user can know the data in real time through the client. Alternatively, the controller of the work machine may send the estimated abnormal leg life loss, remaining life, and/or dangerous event prompts (if any) to the display of the work machine for display so that the driver can know the data in real time.
When the current event executed by the engineering machinery is judged to be a dangerous event, the control system of the engineering machinery can directly trigger or trigger external events of the system through a data platform, such as alarm prompt, control for limiting certain operations (different for different equipment, such as for a pump truck-limited pumping and the like), and remote sending of abnormal event information to a client (of an employer or an equipment administrator).
Optionally, the remote data platform may summarize the above data, hazardous event information, and the like of the mobile construction machine. Therefore, a manufacturer or a management unit can put the landing leg safety information of the engineering machinery which leaves a factory or is under a flag together with other equipment information to carry out effective management. With the abundance of data, the method has positive effect on improving products for manufacturers.
Optionally, the remote data platform of the manufacturer may be a quality management platform thereof, and the mobile engineering machinery leaving the factory can be managed in a full life cycle.
Fig. 3 shows a block diagram of an apparatus for evaluating an abnormal life loss of a leg according to an embodiment of the present invention. As shown in fig. 3, an embodiment of the present invention provides an apparatus for evaluating an abnormal life loss of a leg, which may include: a determining module 310, configured to determine a stress of the supporting point of the leg; the first calculation module 320 is used for calculating the stress change rate of the supporting point of the supporting leg; a first evaluation module 330, configured to evaluate abnormal life loss at the stress analysis point according to the stress of the leg support point and a change rate of the stress of the leg support point; and a second evaluation module 340 for evaluating the remaining life of the leg based on abnormal life loss at one or more of the stress analysis points. The abnormal life loss at the stress analysis point is evaluated according to the stress of the supporting point of the supporting leg and the change rate of the stress of the supporting point of the supporting leg, and then the residual life of the supporting leg is evaluated based on the abnormal life loss at one or more stress analysis points of the supporting leg, so that the reasonable use of engineering machinery by a user is guided, and property loss or construction accidents caused by the damage of the structure of the supporting leg are avoided.
The determination module 310 may calculate the stress of the supporting point of the supporting leg according to the formula (1) by using the first hydraulic oil pressure p1 (t) in the rod cavity of the supporting leg oil cylinder and the second hydraulic oil pressure p0 (t) in the rodless cavity of the supporting leg oil cylinder.
The first calculation module 320 may calculate the rate of change of the force applied to the supporting point of the leg according to equation (2). The first evaluation module 330 may calculate the abnormal life loss at the stress analysis point according to equation (3), (4), or (6). The second evaluation module 340 may calculate the remaining life of the leg according to equation (7).
In some optional embodiments, the apparatus for evaluating an abnormal life loss of a leg according to an embodiment of the present invention may further include: the second calculation module is used for calculating the residual life change rate of the supporting leg; and the prompting module is used for sending out a prompt when the change rate of the remaining service life exceeds the threshold range. The second calculation module may calculate the remaining life change rate of the leg, for example, according to equation (8).
The specific working principle and benefits of the apparatus for evaluating the abnormal life loss of the landing leg according to the embodiment of the present invention are the same as those of the method for evaluating the abnormal life loss of the landing leg according to the embodiment of the present invention, and will not be described herein again.
The specific working principle and benefits of the apparatus for evaluating the remaining life of the leg according to the embodiment of the present invention are the same as those of the method for evaluating the remaining life of the leg according to the embodiment of the present invention, and will not be described herein again.
Accordingly, embodiments of the present invention also provide a machine-readable storage medium having stored thereon instructions for causing a machine to execute the method for evaluating the remaining life of a leg according to any of the embodiments of the present invention.
As will be appreciated by one skilled in the art, embodiments of the present application may be provided as a method, system, or computer program product. Accordingly, the present application may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, the present application may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, and the like) having computer-usable program code embodied therein.
The present application is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the application. It will be understood that each flow and/or block of the flow diagrams and/or block diagrams, and combinations of flows and/or blocks in the flow diagrams and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
In a typical configuration, a computing device includes one or more processors (CPUs), input/output interfaces, network interfaces, and memory.
The memory may include forms of volatile memory in a computer readable medium, random Access Memory (RAM) and/or non-volatile memory, such as Read Only Memory (ROM) or flash memory (flash RAM). The memory is an example of a computer-readable medium.
Computer-readable media, including both permanent and non-permanent, removable and non-removable media, may implement the information storage by any method or technology. The information may be computer readable instructions, data structures, modules of a program, or other data. Examples of computer storage media include, but are not limited to, phase change memory (PRAM), static Random Access Memory (SRAM), dynamic Random Access Memory (DRAM), other types of Random Access Memory (RAM), read Only Memory (ROM), electrically Erasable Programmable Read Only Memory (EEPROM), flash memory or other memory technology, compact disc read only memory (CD-ROM), digital Versatile Disks (DVD) or other optical storage, magnetic cassettes, magnetic tape magnetic disk storage or other magnetic storage devices, or any other non-transmission medium, which can be used to store information that can be accessed by a computing device. As defined herein, a computer readable medium does not include a transitory computer readable medium such as a modulated data signal and a carrier wave.
It should also be noted that the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrases "comprising one of 8230; \8230;" 8230; "does not exclude the presence of additional like elements in a process, method, article, or apparatus that comprises the element.
The above are merely examples of the present application and are not intended to limit the present application. Various modifications and changes may occur to those skilled in the art to which the present application pertains. Any modification, equivalent replacement, improvement or the like made within the spirit and principle of the present application shall be included in the scope of the claims of the present application.
Claims (7)
1. A method for assessing a remaining life of a leg, the method comprising:
determining the stress of a supporting point of the supporting leg;
calculating the stress change rate of the supporting point of the supporting leg;
evaluating abnormal life loss at the stress analysis point according to the stress of the supporting leg supporting point and the change rate of the stress of the supporting leg supporting point; and
evaluating the remaining life of the leg based on abnormal life losses at one or more of the stress analysis points;
wherein the abnormal life loss at the evaluation stress analysis point is calculated according to the following formula:
i k (t)＝G k (f(t),w(t))，
wherein i k (t) is the abnormal life loss at the stress analysis point, f (t) is the stress of the supporting leg supporting point, w (t) is the change rate of the stress of the supporting leg supporting point, k is the number of the stress analysis point, t is time, G k () Is a functional relationship having an integrating or convolution effect on said f (t) and w (t), wherein said G k () Is in positive correlation with f (t) and w (t);
calculating an abnormal life loss at the stress analysis point according to the following formula:
fk1 is a first stress threshold, fk2 is a second stress threshold, fk2 is more than or equal to Fk1, wk1 is a first stress disturbance quantity threshold, wk2 is a second stress disturbance quantity threshold, wk2 is more than or equal to Wk1, wherein Fk1 and Fk2 are obtained according to the maximum allowable stress at the stress analysis point, and Wk1 and Wk2 are obtained according to the maximum allowable stress disturbance quantity at the stress analysis point;
said assessing a remaining life of said leg based on abnormal life losses at one or more of said stress analysis points comprises calculating a remaining life of said leg according to the following formula:
wherein I (T) is the residual life of the support leg, T0 is the design life of the support leg when the support leg is not used abnormally, I k (t) is the abnormal life loss at the stress analysis point, a is a correction coefficient, k is the number of the stress analysis point, n is the number of the stress analysis points, b is the life wear coefficient of the leg, t is time, and ^ b dt represents the life loss caused by the time that the leg has been used.
2. The method of claim 1, wherein the determining the force of the leg support point comprises:
detecting first hydraulic oil pressure in a rod cavity of a supporting leg oil cylinder and second hydraulic oil pressure in a rodless cavity of the supporting leg oil cylinder; and
calculating the stress of the supporting point of the supporting leg according to the following formula:
f(t)＝S1*p1(t)-S0*p0(t)，
f (t) is stress of the supporting point of the supporting leg, S1 is the volume sectional area of a rod cavity of the supporting leg oil cylinder, p1 (t) is the pressure of the first hydraulic oil, S2 is the volume sectional area of a rodless cavity of the supporting leg oil cylinder, and p0 (t) is the pressure of the second hydraulic oil.
3. The method of claim 1, further comprising:
calculating the residual life change rate of the supporting leg; and
and when the remaining life change rate exceeds the threshold range, giving out a prompt.
4. An apparatus for assessing the remaining life of a leg, the apparatus comprising:
the determining module is used for determining the stress of the supporting point of the supporting leg;
the first calculation module is used for calculating the stress change rate of the supporting point of the supporting leg;
the first evaluation module is used for evaluating the abnormal life loss at the stress analysis point according to the stress of the supporting leg supporting point and the change rate of the stress of the supporting leg supporting point; and
a second evaluation module for evaluating the remaining life of the leg based on abnormal life loss at one or more of the stress analysis points;
wherein the first evaluation module calculates the abnormal life loss at the stress analysis point according to the following formula:
i k (t)＝G k (f(t),w(t))，
wherein i k (t) abnormal life loss at the stress analysis point, f (t) stress of the supporting point of the supporting leg, and w (t) stress of the supporting legThe stress change rate of the supporting point, k is the number of the stress analysis point, t is time, G k () Is a functional relationship having an integrating or convolution effect on said f (t) and w (t), wherein said G k () Is in positive correlation with f (t) and w (t);
the first evaluation module calculates an abnormal life loss at the stress analysis point according to the following formula:
fk1 is a first stress threshold, fk2 is a second stress threshold, fk2 is more than or equal to Fk1, wk1 is a first stress disturbance quantity threshold, wk2 is a second stress disturbance quantity threshold, wk2 is more than or equal to Wk1, wherein Fk1 and Fk2 are obtained according to the maximum allowable stress at the stress analysis point, and Wk1 and Wk2 are obtained according to the maximum allowable stress disturbance quantity at the stress analysis point;
the second evaluation module calculates the remaining life of the leg according to the following formula:
wherein I (T) is the residual life of the support leg, T0 is the design life of the support leg when the support leg is not used abnormally, I k (t) is an abnormal life loss at the stress analysis point, a is a correction coefficient, k is the number of the stress analysis points, n is the number of the stress analysis points, b is a leg life wear coefficient, t is time, and fb dt represents a life loss caused by the time the leg has been used.
5. The apparatus of claim 4, wherein the determination module determines the force of the leg support point according to the following steps:
detecting a first hydraulic oil pressure in a rod cavity of a supporting leg oil cylinder and a second hydraulic oil pressure in a rodless cavity of the supporting leg oil cylinder; and
calculating the stress of the supporting point of the supporting leg according to the following formula:
f(t)＝S1*p1(t)-S0*p0(t)，
f (t) is stress of the supporting point of the supporting leg, S1 is the volume sectional area of a rod cavity of the supporting leg oil cylinder, p1 (t) is the pressure of the first hydraulic oil, S2 is the volume sectional area of a rodless cavity of the supporting leg oil cylinder, and p0 (t) is the pressure of the second hydraulic oil.
6. The apparatus of claim 4, further comprising:
the second calculation module is used for calculating the residual life change rate of the supporting leg; and
and the prompting module is used for sending out a prompt when the change rate of the remaining service life exceeds the threshold range.
7. A machine-readable storage medium having stored thereon instructions for causing a machine to perform a method for assessing the remaining life of a leg according to any one of claims 1 to 3.
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Application publication date: 20200825 Assignee: ZOOMLION HEAVY INDUSTRY SCIENCE&TECHNOLOGY Co.,Ltd. Assignor: ZOOMLION HEAVY INDUSTRY SCIENCE&TECHNOLOGY Co.,Ltd. Contract record no.: X2023980042686 Denomination of invention: Method and device for evaluating the remaining life of support legs Granted publication date: 20230411 License type: Common License Record date: 20231010 |