CN105550464A - New submodel finite element analysis method based on cutting boundary deformation constraint - Google Patents

Abstract

The invention discloses a new submodel finite element analysis method based on cutting boundary deformation constraint. The content of the method comprises: building a complete machine simplified model, analyzing; carrying out postprocessing to cutting boundary nodes of the complete machine model; building a finite element model-a submodel of a partial structure; adding a deformation coupling constraint equation to the cutting boundary of the submodel, adding a displacement interpolation boundary condition and a force boundary condition; analyzing the submodel; and checking that the distance from a cutting boundary to a stress gathered region is far enough. The method of the invention is advantaged by that when applying the boundary conditions to the cutting boundary of the submodel, the displacement interpolation boundary condition is added to one part of the cutting boundary, the constraint equation and the force boundary condition are added to the other part; the accuracy of the boundary conditions of the submodel is ensured; compared with the traditional submodel finite element analysis method, in adoption of the new submodel finite element analysis method, the demand of the complete machine model is reduced; the complete machine model is greatly simplified; and the complete machine analysis efficiency and the calculation precision of the submodel are improved.

Description

A kind of new submodel finite element method based on cut-boundary deformation constrain

Technical field

The present invention relates to a Seed model finite element method, particularly a kind of new submodel finite element method based on cut-boundary deformation constrain.

Background technology

In the face of the development trend that current plant equipment maximizes, the problem of big machinery being carried out to complete machine structure finite element analysis is more and more outstanding.Various and the complex structure of heavy mechanical equipment parts, when carrying out finite element structural analysis, in order to complete machine analytical calculation can be realized, certainly will in guarantee bulk deformation and power transmission accurately under prerequisite, whole machine model is simplified greatly, to ensure that its scale of model is within computer capacity tolerance band, at this moment there will be some partial simplified structural stress, strain characteristics cannot calculate or the situation of computational accuracy distortion.In order to the basis that calculates at complete machine simplified model obtaining the accurate result of calculation of some complicated partial structurtes, usually adopt submodel finite element method and cut-boundary displacement method.

Tradition submodel finite element method is also called cut-boundary displacement method or specific border displacement method, cut-boundary is exactly the border that submodel separates from whole more coarse model, the method is based on St. Venant principle, namely after actual distribution load is replaced by equivalent load, stress and strain only changes near the position of load applying, only just there is stress concentration effect in load concentration position, stress at a distance can be disregarded, when the position of submodel is away from stress concentrated position, in submodel, just can obtain more accurate result.

When tradition submodel calculates, stress and displacement meets following relation:

KU＝F(1)

In formula, K is submodel structure global stiffness matrix; F is submodel structure external applied load vector; U is submodel structure motion vector to be asked.

U in (1) formula is divided into two parts: Part I be submodel with other minor structure or units shared, have displacement coordination relation, belong to boundary node displacement, use U ₁represent, be known displacement vector (can be obtained by overall rough model cut-boundary positional displacement interpolation).Part II does not have displacement coordination relation with other minor structure or unit, uses U ₂represent, be motion vector to be asked, therefore, formula (1) can be analyzed to

$\left[\begin{array}{cc}{K}_{11}& K_{12}\\ K_{21}& K_{22}\end{array}\right]\left[\begin{array}{c}{U}_1\\ U_2\end{array}\right]=\left[\begin{array}{c}{F}_1\\ F_2\end{array}\right]---\left(2\right)$

Wherein: U ₁for the displacement array of submodel cut-boundary node; U ₂for submodel internal node displacement array; K ₁₁for submodel boundary node composition stiffness matrix sub-block; K ₂₂for submodel internal node composition stiffness matrix sub-block; F ₁for the node external applied load array of submodel cut-boundary node; F ₂for the node external applied load array of submodel internal node.

(2) formula is launched

[K ₁₁][U ₁]+[K ₁₂][U ₂]＝[F ₁]

(3)

[K ₂₁][U ₁]+[K ₂₂][U ₂]＝[F ₂]

(4)

Through type (4) obtains internal node displacement:

[U ₂]＝[K ₂₂] ^-1[F ₂]-[K ₂₂] ^-1[K ₂₁][U ₁]

(5)

This shows and work as U ₁for time known, without the need to passing through F ₁, can U be tried to achieve ₂.

Utilize above-mentioned thought just can try one's best mesh refinement when computing machine conditions permit, carrying out first time solves.If there is dissatisfied subdomain in result of calculation, can using in this subzone boundaries first time result of calculation as formulation displacement, by formula (5), convert thereof into the load in this subzone boundaries, then grid carried out to this subdomain and again segment and solve.If be still unsatisfied with the result of calculation of be concerned about local subdomain, above-mentioned steps can be repeated until satisfied.

Tradition submodel finite element method is using the boundary condition of the displacement calculating value of block mold cut-boundary as submodel; When carrying out big machinery complete machine finite element analysis model and simplifying, the rigidity of structure of relevant position in the partial structurtes rigidity of submodel and whole machine model usually can be caused to have larger difference; When group rigidity of model and block mold neutron model position rigidity are more or less the same, it is feasible for applying submodel boundary condition like this, and namely from above-mentioned discussion, the prerequisite utilizing traditional submodel finite element method to obtain being satisfied with exact computation results is U ₁for known quantity.But when group rigidity of model differs larger with block mold neutron model position rigidity, apply boundary condition so just infeasible.This is because when the rigidity of submodel changes, if cut-boundary is stressed constant, will there is rigid body displacement in submodel, U ₁a middle part becomes unknown quantity, and the displacement calculating at this moment still applying block mold cut-boundary will cause submodel stress distribution mistake.

Summary of the invention

Instant invention overcomes the deficiencies in the prior art, a kind of new submodel finite element method based on cut-boundary deformation constrain is provided, submodel cut-boundary is divided into two classes, the first kind: cut-boundary nodal displacement is equal with integral cutting boundary displacement, Equations of The Second Kind: cut-boundary nodal displacement and integral cutting boundary displacement not etc., namely do not have rigid body displacement part.So, known displacement vector U ₁two parts can be divided into: Part I is first kind cutting edge displacement array, uses U ₁' represent, be U ₁middle known portions.Part II is Equations of The Second Kind cut-boundary displacement array, uses U ₂' represent, be unknown portions.Then have:

$\left[\begin{array}{cc}{K_{11}}^{,}& {K_{12}}^{,}\\ {K_{21}}^{,}& {K_{22}}^{,}\end{array}\right]\left[\begin{array}{c}{U_1}^{,}\\ {U_2}^{,}\end{array}\right]=\left[\begin{array}{c}{F_1}^{,}\\ {F_2}^{,}\end{array}\right]---\left(6\right)$

Wherein: U ₁' be the displacement array of submodel first kind cut-boundary node; U ₂' be submodel Equations of The Second Kind cut-boundary nodal displacement array; K ₁₁' be submodel first kind cut-boundary node composition stiffness matrix sub-block; K ₂₂' be submodel Equations of The Second Kind cut-boundary node composition stiffness matrix sub-block; F ₁' be the node external applied load array of submodel first kind cut-boundary node; F ₂' be the node external applied load array of submodel Equations of The Second Kind cut-boundary node.Can be obtained by formula (6)

[K ₂₁'][U' ₁]+[K ₂₂'][U ₂']＝[F ₂'](7)

The nodal displacement that through type (7) obtains Equations of The Second Kind cut-boundary node is:

[U ₂']＝[K ₂₂'] ^-1[F ₂']-[K ₂₂'] ^-1[K ₂₁'][U ₁'](8)

This shows, can U be passed through ₁' (displacement of submodel first kind cut-boundary node), F ₂' (the node external applied load of submodel Equations of The Second Kind cut-boundary node), tries to achieve U ₂', thus obtain U ₁, through type (5) can obtain U ₂.So just can by applying positional displacement interpolation boundary condition on submodel first kind cut-boundary, Equations of The Second Kind cut-boundary applies outer force boundary condition, and ensure the compatibility of deformation relation of submodel cut-boundary and block mold cut-boundary, just can try to achieve the displacement and stress fields of submodel.

According to compatibility of deformation relation, overall rough model cut-boundary is identical with the distortion of submodel cut-boundary, and be cut-boundary distortion schematic diagram as shown in Figure 1, wherein a is block mold, and b is submodel.We can utilize this feature, meet by node in submodel Equations of The Second Kind cutting circle adds Degree-of-freedom Coupling relation (that is equation of constraint).

A reference mode n on block mold cut-boundary ₁(x ₁, y ₁, z ₁) and arbitrary node (except n ₁n in addition) _i(x _i, y _i, z _i), with on submodel cut-boundary with reference mode n on block mold cut-boundary ₁(x ₁, y ₁, z ₁) and arbitrary node n _i(x _i, y _i, z _i) corresponding reference mode n ₁' (x' ₁, y' ₁, z' ₁) and arbitrary node n' _i(x' _i, y' _i, z' _i) between relative displacement contact.

After overall rough model analysis completes, block mold cut-boundary reference mode n ₁displacement be U ₁; Arbitrary node n _idisplacement be U _i; Arbitrary node n _ito reference mode n ₁relative displacement be Δ U.

$U_1=\left[\begin{array}{ccc}{U}_{1x},& U_{1y},& U_{1z},\end{array}\right]=\left[\begin{array}{c}{U}_{1x}\\ U_{1y}\\ U_{1z}\end{array}\right]---\left(9\right)$

$U_i={\left[\begin{array}{ccc}{U}_{ix},& U_{iy},& U_{iz},\end{array}\right]}^T=\left[\begin{array}{c}{U}_{ix}\\ U_{iy}\\ U_{iz}\end{array}\right]---\left(10\right)$

$\mathrm{\Δ}U=U_i-U_1=\left[\begin{array}{c}{U}_{ix}\\ U_{iy}\\ U_{iz}\end{array}\right]-\left[\begin{array}{c}{U}_{ix}\\ U_{iy}\\ U_{iz}\end{array}\right]---\left(11\right)$

Submodel Equations of The Second Kind cut-boundary when there is not rigid body and moving, time namely equal with integral cutting boundary displacement, its cut-boundary node reference mode n ₁' displacement array be U ₁'; Arbitrary node is (except n' ₁n' in addition) _idisplacement array be U' _i; Arbitrary node n' _ito reference mode n' ₁relative displacement be Δ U'.

${U_1}^{\′}={\left[\begin{array}{ccc}{U^{\′}}_{1x},& {U^{\′}}_{1y},& {U^{\′}}_{1z},\end{array}\right]}^T=\left[\begin{array}{c}{U^{\′}}_{1x}\\ {U^{\′}}_{1y}\\ {U^{\′}}_{1z}\end{array}\right]---\left(12\right)$

${U^{\′}}_i={\left[\begin{array}{ccc}{U^{\′}}_{ix},& {U^{\′}}_{iy},& {U^{\′}}_{iz},\end{array}\right]}^T=\left[\begin{array}{c}{U^{\′}}_{ix}\\ {U^{\′}}_{iy}\\ {U^{\′}}_{iz}\end{array}\right]---\left(13\right)$

${\mathrm{\ΔU}}^{\′}={U^{\′}}_i-{U^{\′}}_1={U^{\′}}_i=\left[\begin{array}{c}{U^{\′}}_{ix}\\ {U^{\′}}_{iy}\\ {U^{\′}}_{iz}\end{array}\right]-\left[\begin{array}{c}{U^{\′}}_{ix}\\ {U^{\′}}_{iy}\\ {U^{\′}}_{iz}\end{array}\right]---\left(14\right)$

Have according to deformation compatibility condition:

ΔU'＝ΔU(15)

After submodel produces rigid body displacement, cut-boundary node reference point n' ₁rigid body displacement be S ₁; Arbitrary node n' _irigid body displacement be S _i, be block mold and submodel cut-boundary column joints deformation schematic diagram as shown in Figure 2, wherein c is block mold cut-boundary column joints deformation, and d is submodel cut-boundary column joints deformation.Then have:

$S_1=S_1+R=\left[\begin{array}{c}{x^{\′}}_1\\ {y^{\′}}_1\\ {z^{\′}}_1\end{array}\right]---\left(16\right)$

$S_i=S_0+R=\left[\begin{array}{c}{x^{\′}}_i\\ {y^{\′}}_i\\ {z^{\′}}_i\end{array}\right]---\left(17\right)$

Wherein: $S_0=\left[\begin{array}{c}{S}_{0x}\\ S_{0y}\\ S_{0z}\end{array}\right]$ For along X, Y, the translation matrix of Z axis;

$R=\left[\begin{array}{ccc}0& -w_z& w_y\\ w_z& h& -w_x\\ -w_y& w_x& h\end{array}\right]$ For Rigid Body in Rotation With matrix

After submodel generation rigid body displacement, cut-boundary reference mode n' ₁total displacement be arbitrary node n' _itotal displacement be submodel cut-boundary arbitrary node n' _ito reference mode n' ₁relative displacement be

${\stackrel{\‾}{U}}_1={U^{\′}}_1+S_1=\left[\begin{array}{c}{U^{\′}}_{1x}\\ {U^{\′}}_{1y}\\ {U^{\′}}_{1z}\end{array}\right]+\left[\begin{array}{c}{S}_{1x}\\ S_{1y}\\ S_{1z}\end{array}\right]---\left(18\right)$

${\stackrel{\‾}{U}}_i={U^{\′}}_i+S_i=\left[\begin{array}{c}{U^{\′}}_{ix}\\ {U^{\′}}_{iy}\\ {U^{\′}}_{iz}\end{array}\right]+\left[\begin{array}{c}{S}_{ix}\\ S_{iy}\\ S_{iz}\end{array}\right]---\left(19\right)$

$\mathrm{\Δ}\stackrel{\‾}{U}=\stackrel{\‾}{U_i}-\stackrel{\‾}{U_1}=({U^{\′}}_i+S_i)-({U^{\′}}_1+S_1)=({U^{\′}}_i-{U^{\′}}_1)+(S_i-S_1)={\mathrm{\ΔU}}^{\′}+(S_i-S_1)$

$\mathrm{\Δ}\stackrel{\‾}{U}=\mathrm{\Δ}U+\left[\begin{array}{ccc}0& -w_z& w_y\\ w_z& 0& -w_x\\ -w_y& w_x& 0\end{array}\right]\left[\begin{array}{c}{x^{\′}}_i-{x^{\′}}_1\\ {y^{\′}}_i-{y^{\′}}_1\\ {z^{\′}}_1-{z^{\′}}_1\end{array}\right]---\left(20\right)$

That is: $\left[\begin{array}{c}{\stackrel{\‾}{U}}_{ix}\\ {\stackrel{\‾}{U}}_{iy}\\ {\stackrel{\‾}{U}}_{iz}\end{array}\right]-\left[\begin{array}{c}{\stackrel{\‾}{U}}_{1x}\\ {\stackrel{\‾}{U}}_{1x}\\ {\stackrel{\‾}{U}}_{1z}\end{array}\right]=\mathrm{\Δ}U+\left[\begin{array}{ccc}0& -w_z& w_y\\ w_z& 0& -w_x\\ -w_y& w_x& 0\end{array}\right]\left[\begin{array}{c}{x^{\′}}_i-{x^{\′}}_1\\ {y^{\′}}_i-{y^{\′}}_1\\ {z^{\′}}_i-{z^{\′}}_1\end{array}\right]$

That is: $\mathrm{\Δ}U=\left[\begin{array}{c}{\stackrel{\‾}{U}}_{ix}\\ {\stackrel{\‾}{U}}_{iy}\\ {\stackrel{\‾}{U}}_{iz}\end{array}\right]-\left[\begin{array}{c}{\stackrel{\‾}{U}}_{1x}\\ {\stackrel{\‾}{U}}_{1x}\\ {\stackrel{\‾}{U}}_{1z}\end{array}\right]-\left[\begin{array}{ccc}0& -w_z& w_y\\ w_z& 0& -w_x\\ -w_y& w_x& 0\end{array}\right]\left[\begin{array}{c}{x^{\′}}_i-{x^{\′}}_1\\ {y^{\′}}_i-{y^{\′}}_1\\ {z^{\′}}_i-{z^{\′}}_1\end{array}\right]---\left(21\right)$

Formula (21) is the equation of constraint applied on submodel Equations of The Second Kind cut-boundary node.

At this, positional displacement interpolation boundary condition will be applied on submodel first kind cut-boundary node, Equations of The Second Kind cut-boundary node applies external applied load, and the compatibility of deformation relation of Equations of The Second Kind cut-boundary node is called cut-boundary Coupling Deformation submodel finite element method by the submodeling analysis method that the method for the equation that imposes restriction realizes.

The method can effectively simplify complete machine finite element model, improves the computational accuracy of local labyrinth, realizes the finite element analysis of heavy mechanical equipment complete machine structure.

In order to solve prior art Problems existing, the present invention is achieved by the following technical solutions:

Based on a submodel finite element analysis new method for cut-boundary deformation constrain, its content comprises the steps:

Step 1: set up complete machine simplified model and analyze

Utilize APDL parametric modeling language in ANSYS software to set up complete machine by modeling method from bottom to top and simplify finite element model;

Step 2: aftertreatment is carried out to whole machine model cut-boundary node, extract complete machine simplified model cut-boundary resultant force component and node relative displacement, extracting method comprises following particular content:

(1) cut-boundary node is selected;

(2) cut-boundary node total number is extracted, and by node serial number stored in array;

(3) cut-boundary nodal displacement value is extracted;

(4) in cut-boundary node, choose a host node, calculate the relative displacement of each node and host node, and export;

(5) extract cut-boundary acting force, this acting force comprises resultant force component and moment components, and exports;

Step 3: the finite element model setting up partial structurtes---submodel

APDL parametric modeling language in ANSYS software is utilized to be set up the three-dimensional finite element model of submodel by modeling method from bottom to top;

Step 4: add Coupling Deformation equation of constraint at submodel cut-boundary, and add positional displacement interpolation boundary condition and force boundary condition; Submodel first kind cut-boundary node adds positional displacement interpolation boundary condition, submodel Equations of The Second Kind cut-boundary node adds equation of constraint and force boundary condition;

Step 5: carry out submodeling analysis;

Step 6: checking cut-boundary should be enough far away apart from the distance of region of stress concentration.

Owing to adopting technique scheme, a kind of submodel finite element analysis new method based on cut-boundary deformation constrain provided by the invention, compared with prior art has such beneficial effect:

Coupling Deformation constrained procedure is applied at submodel cut-boundary, and apply positional displacement interpolation boundary condition and force boundary condition simultaneously, more traditional submodeling analysis method, group rigidity of model is when relative to block mold, great changes have taken place, still can obtain very accurate stress distribution, ensure that the accuracy of submodel boundary condition.When analyzing in conjunction with complete machine like this, whole machine model can simplify greatly, can either obtain one-piece construction distortion accurately and distribution of force, can obtain again accurate partial structurtes strain and stress distribution.The method application is strong, reduces complete machine finite element model scale, shortens computing time, improve counting yield, improve the computational accuracy of complicated partial structurtes simultaneously, provide a kind of feasible method for heavy mechanical equipment carries out complete machine structure analysis.

During submodel cut-boundary applying boundary condition, part cut-boundary adds positional displacement interpolation boundary condition, another part cut-boundary adds equation of constraint and force boundary condition, ensure that the accuracy of submodel boundary condition, more traditional submodel finite element method analysis method reduces the requirement of whole machine model, greatly can simplify whole machine model, improve the computational accuracy of complete machine analysis efficiency and submodel.

Accompanying drawing explanation

Fig. 1 is cut-boundary distortion schematic diagram, and wherein a is block mold, and b is submodel;

Fig. 2 is block mold and submodel cut-boundary column joints deformation schematic diagram, and wherein c is block mold cut-boundary column joints deformation, and d is submodel cut-boundary column joints deformation;

Fig. 3 is the analysis process figure of a kind of submodel finite element analysis new method based on cut-boundary deformation constrain of the present invention;

Fig. 4 is the data flow figure of a kind of submodel finite element analysis new method based on cut-boundary deformation constrain of the present invention;

Fig. 5 is holistic approach aftertreatment process flow diagram;

Fig. 6 is the structural representation of tri-joint mechanism derricking gear;

Fig. 7 is tri-joint mechanism derricking gear complete machine analysis finite element illustraton of model;

Fig. 8 is that tri-joint mechanism derricking gear complete machine analytical model loads and constraint schematic diagram;

Fig. 9 is tri-joint mechanism derricking gear submodeling analysis finite element model figure;

Figure 10 is that tri-joint mechanism derricking gear submodeling analysis cut-boundary loads and constraint schematic diagram;

Figure 11 is that three kinds of methods calculate bearing pin equivalent stress distribution figure; Wherein, e is that complete machine contact calculates, f is that new Sub Model Method calculates, g is that traditional Sub Model Method calculates.

Embodiment

Below in conjunction with accompanying drawing and embodiment, the present invention is described in further detail:

Based on a submodel finite element analysis new method for cut-boundary deformation constrain, a kind of submodel finite element analysis new method analysis process figure based on cut-boundary Coupling Deformation of the present invention shown in Fig. 3; The method content comprises the steps:

Step 1: set up complete machine simplified model and analyze

Utilize APDL parametric modeling language in ANSYS software to set up complete machine by modeling method from bottom to top and simplify finite element model;

Step 2: aftertreatment is carried out to whole machine model cut-boundary node, extract complete machine simplified model cut-boundary resultant force component and node relative displacement, extracting method comprises following particular content:

(1) cut-boundary node is selected;

(2) cut-boundary node total number is extracted, and by node serial number stored in array;

(3) cut-boundary nodal displacement value is extracted;

(4) in cut-boundary node, choose a host node, calculate the relative displacement of each node and host node, and export;

(5) extract cut-boundary acting force, this acting force comprises resultant force component and moment components, and exports;

Step 3: the finite element model setting up partial structurtes---submodel

APDL parametric modeling language in ANSYS software is utilized to be set up the three-dimensional finite element model of submodel by modeling method from bottom to top;

Step 4: add Coupling Deformation equation of constraint at submodel cut-boundary, and add positional displacement interpolation boundary condition and force boundary condition; Submodel first kind cut-boundary node adds positional displacement interpolation boundary condition, submodel Equations of The Second Kind cut-boundary node adds equation of constraint and force boundary condition;

Step 5: carry out submodeling analysis;

Step 6: checking cut-boundary should be enough far away apart from the distance of region of stress concentration.

With reference to Fig. 4, the figure shows the data flow of the submodel finite element analysis new method based on cut-boundary coupling, data file is ANSYS file.

With reference to Fig. 5, the figure shows holistic approach aftertreatment flow process, this process is implemented in ANSYS software.

Below with a kind of tri-joint mechanism derricking gear for example, whole analysis process and step are described in detail.

Figure 6 shows that a kind of tri-joint mechanism derricking gear, comprise the first bearing 1, second bearing 2, arm body, amplitude oil cylinder and connection bearing pin; It is characterized in that: the first bearing 1 is connected by hinge A with amplitude oil cylinder, the second bearing 2 is connected by hinge B with arm body afterbody, is connected in the middle part of arm body with amplitude oil cylinder by hinge C, arm body head effect rated load P; Pinned connection two components are passed through in hinged place, to meet relatively rotating between component, and transmitting forces; Whole finite element analysis, to the connection bearing pin at hinge B place, is carried out stressing conditions sunykatuib analysis during institution staff, is comprised the following steps:

1, set up complete machine simplified model and analyze

Utilize APDL parametric modeling language in ANSYS software to set up complete machine by modeling method from bottom to top and simplify finite element model; Complete machine simplifies finite element model and comprises the first bearing 1, second bearing 2, arm body and amplitude oil cylinder; Whole machine model calculates for avoiding carrying out contact, hinge B structure is simplified, be connected bearing pin by the second bearing 2 with B place and build up one, arm body is connected bearing pin with B place and also builds up one, then the node that the second bearing 2 and arm body on bearing pin center line coincide is merged, share bearing pin centerline node to simplify simulation B hinge structure by the second bearing 2 and arm body; First bearing 1, second bearing 2, arm body adopt solid186 3D solid unit, and amplitude oil cylinder adopts beam188 unit; By the first bearing 1 bottom surface and the second bearing 2 left side node fixed constraint, apply downward rated load P at arm body head; Complete machine simplifies finite element model with reference to Fig. 7; Complete machine analytical model loads and constraint reference Fig. 8.

2: extract complete machine simplified model cut-boundary resultant force component and node relative displacement

Select cut-boundary node and extract node total number, and by node serial number stored in array; Extract cut-boundary nodal displacement value; In cut-boundary node, choose a host node, calculate the relative displacement of each node and host node, and export; Extract cut-boundary acting force (comprising resultant force component and moment components), and export;

3: the finite element model setting up partial structurtes---submodel

APDL parametric modeling language in ANSYS software is utilized to be set up the three-dimensional finite element model of submodel by modeling method from bottom to top; Submodel comprises the second bearing 2, B hinge connects bearing pin, arm body, all adopts solid186 3D solid unit, with reference to Fig. 9.

4: cut-boundary adds positional displacement interpolation boundary condition, equation of constraint and resultant force component

Apply positional displacement interpolation boundary condition at the cut-boundary of the second bearing 2, apply deformation constrain equation and/resultant moment component of making a concerted effort, with reference to Figure 10 at arm body cut-boundary.

5: carry out submodeling analysis

Above-mentioned submodel is analyzed, draws the equivalent stress distribution figure connecting bearing pin, with reference to Figure 11.

Claims (1)

1., based on a new submodel finite element method for cut-boundary deformation constrain, its content comprises the steps:

Step 1: set up complete machine simplified model and analyze

Utilize APDL parametric modeling language in ANSYS software to set up complete machine by modeling method from bottom to top and simplify finite element model;

Step 2: aftertreatment is carried out to whole machine model cut-boundary node, extract complete machine simplified model cut-boundary resultant force component and node relative displacement, extracting method comprises following particular content:

(1) cut-boundary node is selected;

(2) cut-boundary node total number is extracted, and by node serial number stored in array;

(3) cut-boundary nodal displacement value is extracted;

(4) in cut-boundary node, choose a host node, calculate the relative displacement of each node and host node, and export;

(5) extract cut-boundary acting force, this acting force comprises resultant force component and moment components, and exports;

Step 3: the finite element model setting up partial structurtes---submodel

APDL parametric modeling language in ANSYS software is utilized to be set up the three-dimensional finite element model of submodel by modeling method from bottom to top;

Step 4: add Coupling Deformation equation of constraint at submodel cut-boundary, and add positional displacement interpolation boundary condition and force boundary condition; Submodel first kind cut-boundary node adds positional displacement interpolation boundary condition, submodel Equations of The Second Kind cut-boundary node adds equation of constraint and force boundary condition;

Step 5: carry out submodeling analysis;

Step 6: checking cut-boundary should be enough far away apart from the distance of region of stress concentration.