The integral structure in engineering mechanical design is limited yuan of analysis technology
- source:TECHEN CNC Machining
1 parameter changes design language the CAD model to the structure (be combined by dot, line, face and substance normally and become) undertake parameter changes diagnostic design, it is the basic function of contemporary CAD system. But, to finite yuan of structural analysis system for, to complex combination structure finite yuan the model should realize parameter to change a design, be not easy thing however. Advanced ANSYS system offerred a kind to build parameter to change the language of main tool __APDL of the model for the user. But, use APDL language develops the model program that parameter turns, the thing that is him user however. APDL is one kind faces a project, explanatory sex language of structuralization. It has the main feature of advanced and algorithmic language and function. Its expressive means is a series of basic user orders are strung together. Accord with the program of FEA aprametric model with ANSYS_APDL regular grammar, generally speaking, it includes: Geometry (dot, line, face, hypostatic) definition and operation command, finite yuan unit differentiates command, logic dominates a command, condition and loop command, analytic flow command. What the user wants pair of structural member is finite yuan the model undertakes parameter changes a design, must master this kind of language adroitly. Structure of all and complex combination and overall FEA model want to undertake 2 times developing with APDL language. 2.
The extraction that the parameter of 2 structural member changes structural member parameter is the basis that parameter changes a design. The key here is to choose the main parameter that can state feature of structural member geometry. Popularly says, the main parameter of structural member includes requirement of long, wide, tall, crucial point, join, board thick, profile is sectional indigestion, character of material and physics. We will be right the ground names these parameter standardization, the parameter name that the setting concerns (or array name) . For example, we name length parameter A , .
A[n] , width parameter is W , .
W[m] , high parameter is H , .
H[i] , ply parameter is T , .
T[j] , to each structural member, it has a group of such parameter. Define structural member name to be name of corresponding parameter team, and with / EOF regards an end as accord with, the parameter module of the structural member that this made an APDL can be called. The parameter module of compositive and all structural member, made the file of FEA parameter library of product structure. 2.
The FEA parameter library of 3 products and structure of model library product often are by a few main bear force structural member comprises. Product parameter file contained their corresponding parameter module. These join the change that any parameter of several module are worth, what can cause concerned structural member is finite yuan of change of the model, also cause the change of whole structure. The product of seriation is the series change of these parameter. Of product structure function optimize the design is these parameter. The FEA model program of product structural member and integral structure, use ANSYS/APDL language just about, cite several module are joined accordingly in parameter library, undertake 2 times developing getting. We name the FEA model of the product the library with type name, it includes the parameter library file of the product not only, also include file of program of structural member model, load, operating mode to control a file to wait. Here, it is with library of model of hexagon arm QY25D exemple, show it form. The logistic tree of library of model of model of graph 1 QY25D pursues the logistic tree that 1 watch understands FEA model library, basically include: § BQCDB.
LIB product program designs BQDDB of parameter file § .
CRANE of § of file of parameter of LIB product detailed design.
LIB grand BQC100 of subprogram file § .
A as string of 1 brachial plan designs BQC200 of model program § .
A double wall wears revolving stage plan high to design BQC300 of model program § .
A frame plan designs model program to make clear from product model library, the modification of parameter can get modification structural model directly. This can undertake to the product of same configuration the comparison of plan and parameter are optimized, and make seriation design becomes a possibility. Of 3 whole structure child the structure analyses a technology 3.
The analyse dispenses of 1 whole structure child the basic characteristic of structure of structural analysis whole is structural dimensions form of big, combination is complex. Current, the analytic problem that large and complex structure solves on international chooses normally child structural method, or the structure exceeds unit method. Because exceed unit,be actually child form of a kind of expression, accordingly here only brief meson structure analyses a technology. Large to any complex construction, we always can differentiate to strike part or structural member to be like (abbreviation is child structural) , node of bound of their keep to the side and whole are connected related the structure. If we will all child composition of attrib border node assembles, so this gather token the join framework of this large and complex structure, we say for attrib border structure. Want us only each child the structure is attrib border to concerning the stiffness effect of node (or influence 〕 computation comes out, bring to bear on to go up in these attrib border node, solve the analytic problem of large and complex structure, transform to seek solution scope is little much a certain number of child structure and issue of attrib border construction. Of course, if attrib border structure and child structural scale is very large also, OK still again analyse cent is a certain number of 2 class or of 3 class child structure. But, this kind multiple child structural use, complication those who bring analytic technological process. Accordingly, how the crucial seat that effectively analyse divided integral structure to become an issue. We express with K child total stiffness matrix of the structure, u expresses child total displacement matrix of the structure, p expresses child total load matrix of the structure; Ki expresses only with child the stiffness matrix related structural interior node, kb expresses only with child the stiffness matrix related structural border node, kib expresses child the stiffness matrix;Pi of couplet expresses related structural interior node and attrib border node only with child related structural interior node outside load matrix, pb expresses only with child the load matrix related structural border node; Ui expresses child matrix of in-house node displacement, ub expresses child matrix of exterior node displacement. We will have balance equation: KU = P(1) among them, here, namely child of the structure only related to attrib border node the matrix of equivalent and attrib border stiffness of couplet and matrix of equivalent and attrib border load. They are right the contribution of integral structure and child structural contribution comparatives, be weighed consequently to exceed unit. Once the displacement of attrib border node is foregone, of the structure inside the displacement of node by the analysis of structure of two pairs of formulary Ui = Ki-1(Pi-KibUb) (4) , its basically are calculated workload is to eliminate this child in-house node freedom of the structure is spent, get its equivalent matrix. From (2) , (3) type can see, if each child attrib border node of the structure is less, criterion the scope of these equivalent matrix is less also, final border child structural scope is less also, its operation rate is rapidder also. Accordingly, differentiate a when complex structure is much stature structure basic method, should control as far as possible namely child in-house node dimensions of the structure is appropriate, and have the number of attrib border node less. For example, make full use of structural chain, outside extend wait for a characteristic, reasonable delimit molecular structure, can get better result. 3.
2 child structural commutation and assemble in analysis of general whole structure, using 4 kinds of coordinate is. Among them, the department of coordinate of directional; element that node coordinate department decided to node freedom is spent set elemental stiffness (load) matrix and child the commutation matrix; between the structure child structural coordinate department will decide child stiffness of structural equivalent border (load) matrix to integral structure assemble. To child for structural analysis, child structural geometry builds model and stress analysis is to be in child local coordinate of the structure fastens next undertaking. But, child equivalent stiffness of the structure (load) matrix must undertake assembly by overall coordinate department however. Accordingly, before each stature structure is being assembled, need attrib border to equivalent stiffness (load) matrix undertakes coordinate alternates. We set B to be child the structural commutation to total faculty matrix (3 node that normally it fastens by whole are affirmatory: Node 1 definition origin, node 1-2 direction defines X to, the planar normal that node 1-2 connects even line and node 1-3 definition the line to form decides Z to, define Y to the planar normal that form by Z and X to) , the border of whole structure child structural stiffness (load) matrix explains to be worth, here.
It is the position of attrib border node number that presses total construction, of overlay of check the number. Accordingly, the equation of attrib border balance of integral structure is: KzUz = Pz (7) gives the obligation that freedom of 6 rigid body spends integral structure, seek solution (7) , we will get the displacement of integral border structure. The coordinate of structure of Xiang Zi of displacement of repass whole border alternates, carry out (4) type, will get child in-house node freedom of the structure is spent. 3.
Of model of 3 whole structure simplify the criterion analysis to integral structure, need to try all structural member and orgnaization to consider not only, and the different load operating mode in process of need general exercise tries to consider. To control the dimensions that integral structure analyses, of integral model build want already as far as possible Utopian, simplification, model is changed, want again relatively mirror a whole objectively (especially place of structural member join) stress distributings, be out of shape (stiffness) reach the issue such as invalidation. The exercise motion of integral structure makes clear, be necessary to choose a variety of typical exercise operating mode to try to calculate; At the same time even according to project standard, consideration wind carries, inertial carry, the effect that the imparity much element of work place suffers force to integral structure. Because the complexity of integral structure and control structure analyse the need of dimensions, of integral structure model simplify be based on undermentioned principle: ¨ ensures the line sending force of integral structure is complete ¨ ensures the parameter of the practical ¨ crucial structural member of operating mode of exercise of integral construction type changes structural member parameter ¨ change unified ¨ to be opposite with integral structure parameter it is important that detail structure of the structure is made simplify ¨ whole structure is limited Yuan Jianmo and analysis. 3.
The model of compositive and compositive structural member of model of 4 whole structure builds a model with achieving integral structure, turned structural member into the model actually assemble with join. The assembly of structural member must undertake below total faculty. The first pace should be installed child structural coordinate is, defining origin and coordinate is direction, the model program that the 2nd pace wants to call relevant structural member produces geometrical model automatically, restore total faculty even finally. The join of structural member, also undertake below total faculty. Different join kind needs to build different join structure, so that imitate structural member is in,total construction expresses power concern mediumly. For example, automobile crane, a string of 1 there is luffing oil cylinder between arm and revolving stage; Condole arm axis of rotation, the steel wire of windlass is pure wait for join must give simplify; Circumgyrate props up fluctuation gasket of the structure to be able to regard music as Liang Yuan; The imitate of ball and bolt upright props up a structure to want those who share revolving stage and frame platform to defy a turn, it is the technical point that deserves attention. For example, the tie-in of the frame of the motor that mine uses a car, reducer, turn to an orgnaization to wait, what all participated in frame is overall get power, in bold when simplifying, also need those who build corresponding imitate structure is finite yuan of model. The automation technological process that 4 whole structure analyses 4.
The parameter of model of 1 whole structure changes the parameter of integral structure model is with child of foundation of structural parameter melt into. As a result of integral structure child the structure differentiates is with the key structural member is entity. Accordingly, the parameter of structural member changes the parameter with integral structure to change union of OK and organic ground to rise, build file of unified structural parameter library. 4.
The model of the structural member of FEA model program of 2 structural member produces a program automatically is developed for platform with APDL language, it will call the relevant module of file of structural parameter library. Once the parameter of implementation structural member is changed,want only, its geometrical model produces a program automatically with grand subprogram means is built with call. This made model of structural member geometry grand library. The geometrical model of structural member and integral structure all calls this grand library arises, this very the harmony that is helpful for integral structure analysis and structural member analysis. In the meantime, the attrib border condition that the certain result that integral structure analyses also can regard structural member as introduces with automatic means. 4.
The basic measure that 3 whole structure analyses now, the basic measure that we can analyse to integral structure makes proper standard: ¨ builds the ¨ of parameter library file that is basic module with structural member to be platform with APDL, develop model of structural member FEA grand library ¨ is called grand library, the ¨ of automation analysis flow that develops the compositive program ¨ of integral structure model to build integral structure builds postposition to handle flow 4.
4 flow design is based on afore-mentioned technical courses, we press functional design requirement very easily, build a certain number of structures to analyse technological process automatically. Graph 2 it is the block diagram of general analysis flow that is based on ANSYS/APDL 2 times to develop. Among them, FEA model program is the APDL language development that uses ANSYS, the structural design with new product is close together and relevant; It cites model parameter of the structure and load data file; Solution calculates implement reach an aftertreatment implement the basic function module that is ANSYS. Here, the fundamental analysis flow that we build has: § structural member analyses technological process; Realize model of FEA of each structural member to arise automatically to be analysed with stress; § whole structure analyses technological process: The model of FEA of each structural member that achieves integral structure is generated, assemble reach stress analysis. Stability of § structural member analyses technological process - model of structural member FEA is generated related implementation reach stability analysis. Graph 2.
5 whole structure analyses the 2 development technological process that is based on ANSYS_APDL to apply mediumly in heavy-duty mechanical design 5.
The integral structure of QY25D of 1 automobile crane analyses us to be opposite Beijing crane implement the factory is hexahedral the automobile crane QY25D of 4 arms undertook overall the structure is limited yuan of analysis. This is this industry is opposite overall analytic first time is admired try. Whole structure differentiates to reach a certain number of join structures for 3 stature structures, built two to use at overall order flow of the analysis: A.
What complete aircraft program designs is finite yuan parameter changes a model to produce a program, its are main the function is right model of design of complete aircraft program undertakes finite yuan of analysis. In analysing a process, overall the model has 3067 node; Shell63 element 3149, beam4 element 133, link8 element 1; Effective freedom is spent for 17597. B.
The complete opportunity that has model of detailed design frame is finite yuan parameter changes a model to produce a program, its are main the function is local to having frame those who strengthen is overall the model undertakes finite yuan of analysis. In analysing a process, overall the model has 4367 node, shell63 element 4471, beam4 element 217, link8 element 1; Effective freedom is spent for 25166. Plan A and plan B make clear quite, ministry of model network structure is refined, can make the model analyses dimensions to increase. Graph 3, 4 make clear overall analytic stress distributings cloud atlas. Overall stress level and the validity that the rationality that distributing proved the method of article introduction. But, the application outside field makes clear, the local stability of structural member still is worth to take seriously. Graph 3 QY25D is overall cloud atlas of analysis of Von Mises stress pursues 4 overall analytic Y to local be out of shape analyse cloud atlas with stress 5.
2 mine use frame of heavy-duty car BJZ3480 whole analysed us to undertake whole to the BJZ3480 of Beijing heavy-duty automobile factory frame finite yuan of analysis. Integral structure differentiates for 5 stature structures, a certain number of join structure. Final integral model has 6769 node, 7105 finite yuan of element, among them, housing is unit (Shell63) has 7027, bridge is unit (Beam4) has 78; Structural total number of degrees of freedom 40614. Integral structure analysis got frame is in lift litre, brake, turn Ji Jingman grows those who wait for 4 kinds of different operating mode to fall to be out of shape with stress level (see a picture 5, 6, 7, 8) . This is this factory first time to so complex combination the structure undertakes finite yuan of analysis, the result makes a person Man Yi. Frame of graph 5 BJZ3480 lifts those who rise operating mode to draw the crucial position that controls 6 BJZ3480 of graph of stress cloud atlas to lift litre of operating mode tie-in of 7 BJZ3480 of graph of integrated stress cloud atlas when brake operating mode pull press stress cloud atlas frame of graph 8 BJZ3480 is static the local stress cloud atlas that is fully loaded with operating mode 5.
3The inflectional analysis of QY25D condole arm we use integral structure parameter to turn the model of condole arm structural member in building a model, undertake taking geometry big metabolic is nonlinear inflectional analysis  , use ANSYS basic algorithm is: Iterative method of method of automatic load increment, Newton_Raphson, reach take amendatory Newton_Raphson automatic iterative method. Those who pass much operating mode is nonlinear inflectional analysis proof, the condole arm of QY25D uses be stability inside project standard. But, when the structure extends state completely, interference basically is side carries, exceed the biggest total condole to weigh the circumstance of 10% to fall, the structure will be broken firm, its are critical load factor is 0.
8, break firm the 25kg/mm**2 of stress of the biggest Von Mises before. Graph 9, 10 be break below serious operating mode firm before be out of shape with stress cloud atlas. Graph the detailed design model of 3 breaks operating mode of arm of the 3rd 9 condole firm before be out of shape with stress cloud atlas pursues the detailed design model of 4 breaks operating mode of arm of the 3rd 10 condole firm before be out of shape with stability of stress cloud atlas the analysis makes clear, the level of linear static stress that is a structure namely is in allowable inside stress limits, stability analysis of the structure is very necessary still. CNC Milling CNC Machining