2022年ABAQUS中定義彈簧單元分解

1、精選學(xué)習(xí)資料 - - - 歡迎下載abaqu中s定義彈簧單元精品學(xué)習(xí)資料精選學(xué)習(xí)資料 - - - 歡迎下載2021-12-16 17:57abaqus analysis user's manual29.1.1springsproducts: abaqus/standardabaqus/explicitabaqus/caereferencesoverviewspring elements:can couple a force with a relative displacement;inabaqus/standardcan couplea momentwitha relativerota

2、tion; can be linear or nonlinear;if linear、 can be dependent on frequency in direct-solution steady-state dynamic analysis;can be dependent on temperature and field variables; and can be used to assign a structural damping factor to form the imaginary part of spring stiffness.the terms“force ” and“d

3、isplacement ” are used throughout the description of spring elements. when the spring is associated with displacement degrees of freedom、 these variables are the force andrelative displacementinthe spring.if the springsare associated with rotational degrees of freedom、 they are torsional springs; th

4、esevariables will then be the moment transmitted by the spring and the relative rotation across the spring.viscoelastic spring behavior can be modeled in abaqus/standardby combiningfrequency-dependentspringsand frequency-dependentdashpots.typical applications精品學(xué)習(xí)資料精選學(xué)習(xí)資料 - - - 歡迎下載spring elements ar

5、e used to model actual physical springs as well as idealizations of axial or torsional components. they can also model restraints to prevent rigid body motion.they are also used to represent structural dampers by specifying structural damping factors to form the imaginary part of the spring stiffnes

6、s.choosing an appropriate elementspring1 and spring2 elements are available only in abaqus/standard. spring1isbetween a node and ground、actingina fixeddirection.spring2 is between two nodes、 acting in a fixed direction.the springa element is available in both abaqus/standard andabaqus/explicit.sprin

7、gaactsbetween two nodes、withitslineofaction being the line joining the two nodes、 so that this line of action canrotate in large-displacement analysis.the spring behavior can be linear or nonlinear in any of the spring elements in abaqus.element types spring1 and spring2 can be associated with displ

8、acement or rotational degrees of freedom in the latter case、 as torsionalsprings. however、 the use of torsional springs in large-displacementanalysis requires careful consideration of the definition of totalrotationat a node; therefore、connectorelements are usuallya better approach to providing tors

9、ional springs for large-displacement cases.inputfileusage:use the following option tospecifya springelement between a node and ground、 acting in afixed direction:、 type=spring1use the following option tospecifya springelement between two nodes、 acting in a fixed direction:、 type=spring2use the follo

10、wing option tospecifya springelement between精品學(xué)習(xí)資料精選學(xué)習(xí)資料 - - - 歡迎下載two nodes withitslineof action being the line joining the two nodes:、 type=springaabaqus/caeusage:property or interaction module:specialsprings/dashpotscreate、 of the following:then selectoneconnect pointsto ground :selectpoints:togg

11、leon spring stiffness equivalent to spring1connect two points: select points:axis : specify fixed direction: toggle onspring stiffness equivalent to spring2connect two points:selectpoints:axis : follow line of action: toggle onspring stiffness equivalent to springastability considerations in abaqus/

12、explicita springa element introduces astiffnessbetween two degrees of freedom withoutintroducingan associatedmass. inan explicitdynamic procedure thisrepresents anunconditionallyunstable element.the nodes towhich the spring is attached must have some mass contribution from adjacentelements;ifthiscon

13、ditionisnot satisfied、abaqus/explicitwillissue an errormessage. ifthe springisnot too stiffrelativeto the stiffness of the adjacent elements、 the stable time increment determined by theexplicit dynamics procedure will suffice to ensure stability of the calculations.abaqus/explicit does not use the s

14、prings in the determination of the stable time increment. during the data check phase of the analysis、abaqus/explicit computes the minimum of the stable time increment forall the elements in the meshexcept the spring elements. the program then uses this minimum stable time increment and the stiffnes

15、s of each of the springs to determine the mass required for each spring to give the samestable time increment. if this mass is too large compared to the massof the model、abaqus/explicitwillissuean errormessagethatthespring精品學(xué)習(xí)資料精選學(xué)習(xí)資料 - - - 歡迎下載is too stiff compared to the model definition.relative

16、displacement definitionthe relative displacement definition depends on the element type. spring1 elementsthe relative displacement across aspring1 element is thei th component of displacement of the spring's node:where iis defined as described below and can be in a local direction see”.spring2 e

17、lementsthe relative displacement across a spring2 element is the differencebetween thei thcomponent ofdisplacementofthespring'sfirstnode and thej th component of displacement of the spring's second node:where iand jare definedas describedbelow and can be in localdirections see”.it is importa

18、nt to understand how the spring2 element will behaveaccording to the above relative displacement equation since the element can produce counterintuitive results. for example、 a spring2element set up in the following way will be a“compressive ” spring:if the nodes displace so that and 、 the spring ap

19、pears to be incompression、whilethe forceinthe spring2element ispositive.to obtain a “tensile” spring、 the spring2 element should be set up in the following way:springa elementsfor geometricallylinearanalysistherelativedisplacementismeasured along the direction of the springa element in the reference

20、configuration:where is the reference position of the first node of the spring and is the reference position of its second node.for geometrically nonlinear analysis the relative displacement acrossa springaelement isthe change inlengthinthe springbetween the initial精品學(xué)習(xí)資料精選學(xué)習(xí)資料 - - - 歡迎下載and the curr

21、ent configuration:where is the current length of the spring and is the value oflin the initial configuration. here and are the current positions of the nodesof the spring.in either case the force in aspringa element is positive in tension.defining spring behaviorthe spring behavior can be linear or

22、nonlinear. in either case you must associate the spring behavior with a region of your model.inputfileusage:、 elset=namewhere the elsetparameterrefers to a set of spring elements.abaqus/caeusage:property or interaction module:specialsprings/dashpotscreate: select connectivity type: select pointsdefi

23、ning linear spring behavioryou define linear spring behavior by specifying a constant spring stiffness force per relative displacement.the springstiffnesscan depend on temperatureand fieldvariables.see 、 forfurtherinformationabout definingdataas functions oftemperature and independent field variable

24、s.for direct-solution steady-state dynamic analysis the spring stiffness can depend on frequency、 as well as on temperature and field variables.if a frequency-dependent spring stiffness is specified for any otheranalysisprocedureinabaqus/standard、the dataforthe lowestfrequency given will be used.inp

25、utfileusage:、 dependenciesnf=irst data linespring stiffness、 frequency 、temperature 、field精品學(xué)習(xí)資料精選學(xué)習(xí)資料 - - - 歡迎下載variable 1、 etc.abaqus/caeusage:property or interaction module:specialsprings/dashpotscreate: selectconnectivity type: select points:property:spring stiffness:spring stiffnessdefining the

26、 spring stiffness as a function of frequency、 temperature、 and field variables is not supported in abaqus/cae when you define springs as engineering features; instead、 you can define connectors that have spring-like elastic behavior see .defining nonlinear spring behavioryou define nonlinearspringbe

27、haviorby givingpairs offorce relative displacement values. these values should be given in ascending order ofrelative displacement and should be provided over a sufficiently widerange of relative displacement values so that the behavior is definedcorrectly.abaqus assumes thatthe forceremains constan

28、twhichresults in zero stiffness outside the range given see .figure 29.1.11 nonlinear spring forcerelative displacement relationship.initial forces in nonlinear springs should be defined as part of therelationshipby givinga nonzero force、atzerorelativedisplacement.the spring stiffness can depend on

29、temperature and field variables. see 、 for further information about defining data as functions of temperature and independent field variables.abaqus/explicit will regularize the data into tables that are definedin terms of even intervals of the independent variables. in some caseswhere the forceisd

30、efinedat uneven intervalsof the independentvariable relative displacement and the range of the independent variable islarge compared to the smallest interval、 abaqus/explicit may fail to obtain an accurate regularization of your data in a reasonable number of intervals. in this case the program will

31、 stop after all data areprocessedwithan errormessagethatyou must redefinethematerialdata.精品學(xué)習(xí)資料精選學(xué)習(xí)資料 - - - 歡迎下載see 、 for a more detailed discussion of data regularization.inputfileusage:、 nonlinear、 dependenciensfi=rst data lineforce、relative displacement 、temperature 、 field variable 1、 etc.abaqus

32、/caeusage:defining nonlinear spring behavior is notsupported in abaqus/caewhen you define springs as engineering features; instead、 you can define connectors that have spring-like elasticbehavior see .definingthedirectionofactionforspring1and spring2elementsyou define the direction of action for spring1 and spring2 elements by giving the degree of freedom at each node of the element. this degreeof freedom may be in a local coordinate system . the local system is assumed to be fixed: even in large-displacement analysis spring1 and spring2 eleme