UG有限元高级仿真真正有用的资料

UG有限元高级仿真真正有用的资料 高级仿真 高级仿真 .................................................................................................................................. 1 NX Nastran structural analysis and solution types ............................................................................ 2 NX Nastran thermal analysis and solution types .............................................................................. 4 线性静态分析 ................................................................................................................................... 4 Supported linear static analysis types ...................................................................... 4 Using materials for a linear static analysis ................................................................................ 5 Defining boundary conditions for a linear static analysis ......................................................... 5 Using the iterative solver .......................................................................................................... 5 模态分析........................................................................................................................................... 6 Supported modal analysis types ................................................................................................ 6 Using materials for a modal analysis ........................................................................................ 7 Defining boundary conditions for a modal analysis .................................................................. 7 Setting modal solution attributes ............................................................................................... 7 Reviewing modal analysis results ............................................................................................. 8 如何判断模态的频率 ............................................................................................................... 9 线性曲屈分析 ................................................................................................................................... 9 Buckling analysis introduction .................................................................................................. 9 Linear buckling assumptions................................................................................................... 10 Supported buckling analysis types .......................................................................................... 10 Using materials for a buckling analysis .................................................................................. 10 Defining boundary conditions for a buckling analysis ............................................................ 10 Reviewing buckling analysis results ....................................................................................... 11 Nonlinear static analysis introduction ............................................................................................. 11 Supported nonlinear solution types ......................................................................................... 12 Whether to use a nonlinear solution ........................................................................................ 12 Using elements for solution type NLSTATIC 106 .................................................................. 13 Using elements for solution type ADVNL 601, 106 ............................................................... 13 Using materials for solution types NLSTATIC 106 and ADVNL 601, 106 ............................ 14 Entering stress/strain data for solution types NLSTATIC 106 and ADVNL 601, 106 ............ 14 Defining boundary conditions for solution types NLSTATIC 106 and ADVNL 601, 106 ..... 15 NLSTATIC 106的求解设置 .................................................................................................. 15 ADVNL 601, 106的求解设置 ............................................................................................... 16 响应仿真......................................................................................................................................... 17 仿真步骤................................................................................................................................. 17 Special boundary conditions ................................................................................................... 18 Solution attributes for Response Simulation ........................................................................... 20 FRF and Transmissibility ........................................................................................................ 20 Analysis events ....................................................................................................................... 21 Excitation loads ....................................................................................................................... 22 Function tools for Response Simulation utility ....................................................................... 22 Sensors .................................................................................................................................... 23 Strain gages ............................................................................................................................. 23 产生整个模型在极值点处的响应 ......................................................................................... 24 柔体分析......................................................................................................................................... 24 Flexible bodies workflow........................................................................................................ 24 Advanced Simulation steps ............................................................................................. 24 Motion Simulation steps ................................................................................................. 25 Connecting the flexible body FEM to the mechanism ............................................................ 25 Defining connection and load degrees of freedom .................................................................. 25 NX Nastran structural analysis and solution types Analysis type Solution type Description Linear Static SESTATIC101 – Structural solve used to solve linear and some nonlinear Single Constraint problems, such as gaps and SESTATIC101 – contact elements. Multi-Constraint SESTATIC101 – Superelement Modal Analysis Evaluates normal modes and SEMODES103 natural frequencies. SEMODES103 – Response Simulation SEMODES103 – Superelement SEMODES103 – Flexible Body Linear Buckling SEBUCKL105 Determines buckling loads and buckled mode shapes. Nonlinear NLSTATIC106 Considers geometric and Statics material nonlinear behavior. Analysis type Solution type Description Direct SEDFREQ 108 Frequency response is Frequency calculated directly (without Response normal modes). Direct SEDTRAN 109 Transient response is Transient calculated directly (without Response normal modes). Modal Frequency SEMFREQ 111 Frequency response is based on Response previously solved normal modes. Modal Transient SEMTRAN 112 Transient response is based on Response previously solved normal modes. Nonlinear NLTRAN 129 Dynamic transient response is Transient calculated, which includes Response (NLSTATIC 106) nonlinear conditions. Advanced ADVNL 601,106 Considers geometric and Nonlinear material nonlinear behavior. Statics (implicit) Advanced ADVNL 601,129 Dynamic transient response is Nonlinear calculated, which includes Transient nonlinear conditions. Response (implicit) Advanced ADVNL 701 Calculates dynamic responses Nonlinear with nonlinear effects. Dynamic Analysis (explicit) Design DESOPT 200 Adjusts the defined design Optimization variables within the limits you specify as it searches for the optimum conditions, while working in the scope of your overall optimization objective and output constraints. Axisymmetric SESTATIC101 - Solves an FE model that is Structural defined for only a section cut on Analysis type Solution type Description one side of the axis of an Multi-Constraint axisymmetric part. This greatly NLSTATIC106 reduces the degrees of freedom (DOF) and hence also ADVNL 601,106 significantly reduces solution time. ADVNL 601,129 NX Nastran thermal analysis and solution types Solution Analysis type Description type Steady State NLSCSH153 Thermal analysis. Heat Transfer Thermal analysis for an FE model that is Axisymmetric defined for only a section cut on one NLSCSH153 Thermal side of the axis of an axisymmetric part. 线性静态分析 Supported linear static analysis types In Advanced Simulation, you can choose from the following linear static analysis types when you create a structural solution. Solver Solution type NX Nastran SESTATIC101 - Single Constraint MSC Nastran Solver Solution type NX Nastran SESTATIC101 - Multi-Constraint MSC Nastran ANSYS Linear Statics ABAQUS Static Perturbation substep Using materials for a linear static analysis Material types that can be used in a linear static analysis include: , Isotropic , Orthotropic , Anisotropic , Laminate Defining boundary conditions for a linear static analysis Boundary conditions for linear static analysis can be geometry-based or finite element-based. Examples include: , Point and edge forces , Face loads , Temperature loads , Displacement constraints , Coupled degrees of freedom Using the iterative solver You can turn on the Element Iterative Solver option on the Solution dialog box, or when you are prompted after you start a solve. The iterative solver: , Can be faster, uses less memory, and has fewer disk requirements than the standard sparse matrix solver. , Can be used for a linear static analysis that does not include contact. , Shows the best performance gain with models composed mostly of solid elements. , Is very efficient for models composed mostly of parabolic tetrahedral elements. 模态分析 Supported modal analysis types In Advanced Simulation, you can choose from the following modal analysis types when you create a structural solution: Solver Solution type SEMODES 103 SEMODES 103 - Response Simulation NX Nastran SEMODES 103 - Superelement SEMODES 103 - Flexible Body SEMODES 103 MSC Nastran SEMODES 103 - Superelement Solver Solution type ANSYS Modal ABAQUS Frequency Perturbation substep Using materials for a modal analysis Material types that can be used in a modal analysis include: , Isotropic , Orthotropic , Anisotropic , Fluid Defining boundary conditions for a modal analysis Boundary conditions for modal analysis include constraints and gluing, such as: , Displacement constraints. , Coupled degrees of freedom. , Surface-to-surface gluing Setting modal solution attributes For a modal analysis, some of the NX Nastran solution attributes include: , Max Job Time , Output Requests , Real Eigenvalue Extraction Data. Identifies the type of solve: Lanczos or Householder. , Lanczos Method or Householder Method. The method specifies the real eigenvalue extraction options for the solution. Eigenvalue extraction options are stored as a solver-specific object. Lanczos is the recommended method for most models; Householder is recommended for smaller models. The options include frequency range lower and upper limits, and the number of desired modes. , Default Temperature For more information, see Solvers and Solutions?Setting Nastran Solution Options in the Advanced Simulation online Help. Reviewing modal analysis results Natural frequencies and mode shapes are the primary results for a modal solution. , The results are ordered by frequency, with the lowest natural frequency being the first mode shape, the next highest being the second mode, and so on. , The normal modes represent dynamic states in which the elastic and inertial forces are balanced when no external loads are applied. The magnitude of the mode shapes is arbitrary. , The amplitude of the displacement is not significant, but the relative displacement of the nodes is significant. , Mode shapes help you determine what load locations and directions will excite the structure. 如何判断模态的频率 The first 6 modes have extremely low frequencies. These are rigid body modes. Mode 7 represents the first flexible mode with a natural frequency of about 133 Hz. 线性曲屈分析 Buckling analysis introduction Buckling analysis: , Determines buckling loads and buckled mode shapes. o A buckling load is the critical load at which a structure becomes unstable. o A buckled mode shape is the characteristic shape associated with a structure's buckled response. , Identifies the critical load factor, which is the value that can be multiplied by the applied load to cause buckling. Linear buckling assumptions The buckling analysis uses linear theory. The following assumptions and limitations apply: , The deflections prior to buckling are small. , The reference equilibrium configuration is the initial geometry of the part. , The response of the structure prior to buckling exhibits a linear relationship between stress and strain. , Post-buckling behavior is not predicted Supported buckling analysis types In Advanced Simulation, you can choose from the following buckling analysis types when you create a buckling solution: Solver Solution type NX Nastran SEBUCKL 105 MSC Nastran ANSYS Buckling ABAQUS Buckling Perturbation Substep Using materials for a buckling analysis Material types that can be used in a buckling analysis include: , Isotropic , Orthotropic , Anisotropic Defining boundary conditions for a buckling analysis For a buckling analysis: 1. Define constraints. Constrain the model as you would for a linear static analysis. 2. Apply loads. The load set can contain more than one load type (Force, Pressure), but every load will be scaled by the load factor. A magnitude of 1 is often used when a single load type will cause the model to buckle. Reviewing buckling analysis results For NX Nastran results, buckling analysis results are listed as: , A set of static analysis results for the buckling loads subcase. , A set of modes for the buckling methods subcase. o Each mode has an eigenvalue (load factor) listed. o The applied load multiplied by the buckling load factor is the load at which the part will buckle. o The first mode has the lowest buckling load factor and is usually the mode of most interest. o If the buckling load factor is below 1, the part has buckled. 如果eigenvalue小于1，那么这个模型就已经发生曲屈。 The critical load is the product of the applied load and the eigenvalue for Mode 1.比如在本例中施加的载荷为1N,而Mode 1的对应值为 1380，那么这个临界载荷为1x1380N. Nonlinear static analysis introduction The nonlinear solution types NLSTATIC 106 and ADVNL 601, 106 are capable of simulating the following conditions: geometric nonlinear, material plasticity, and hyperelasticity. This introduction presents two of these nonlinear conditions: , Material plasticity – Material data is entered that describes both the linear elastic and the plastic yield portion of the stress strain curve. , Geometric nonlinear – Pressure loads and element stiffness are updated as the solution iterates. Large geometry displacements and rotation are supported. NLSTATIC 106 and ADVNL 601, 106 solutions can include material plasticity and geometric conditions separately or simultaneously. Supported nonlinear solution types In Advanced Simulation, you can choose from the following nonlinear solution types when the Analysis Type is set to Structural. Solver Solution type NLSTATIC 106 ADVNL 601, 106 NX Nastran ADVNL 601, 129 ADVNL 701 MSC Nastran NLSTATIC 106 ANSYS Nonlinear Statics ABAQUS General Analysis Whether to use a nonlinear solution An SESTATIC 101 linear static solution: , Calculates the element stiffness (K) matrix once at the beginning of the solution. , Assumes Hooke's law, Force = K U, to calculate displacements (U). , Does not account for large displacements and rotation. , Will not update pressure load directions. An NLSTATIC 106 or ADVNL 601, 106 solution with geometric nonlinear conditions: , Iterates (迭代)to follow a nonlinear force/displacement path. , Periodically (定期的)updates the element stiffness matrix while following the nonlinear force/displacement path. , Uses a strain definition which accounts for large displacements and rotations. , Uses the current configuration of a deformed structure to determine the direction of pressure loads. A stiffness change may be a result of both geometry and material nonlinear effects if both are included in the analysis. 几何非线性 Using elements for solution type NLSTATIC 106 For solution type NLSTATIC 106, nonlinear elements may be combined with linear elements for computational efficiency if the nonlinear effects can be localized. The supported nonlinear elements include: , 3D 4-noded and 10-noded tetrahedral solid elements. , 3D 8-noded hexahedral solid elements. , 3D 6-noded pentagonal solid elements. , 2D 4-noded quadrilateral or 3-noded triangular thin shell elements. , 1D 2-noded bar, beam, rod, and spring elements. , GAP elements are created when “contact mesh” or “surface contact mesh” mesh mating conditions are defined. NLSTATIC 106 solution treats the GAP element as a nonlinear gap element in which the gap conditions update as the nonlinear solution iterates. Using elements for solution type ADVNL 601, 106 For solution type ADVNL 601, 106, the supported nonlinear elements include: , 3D 4-noded and 10-noded tetrahedral solid elements. , 3D 8-noded and 20-noded hexahedral solid elements. , 3D 6-noded and 15-noded pentagonal solid elements. , 3D 5-noded and 13-noded pyramid solid elements. , 3D 4-noded and 8-noded or 3-noded and 6-noded axisymmetric thin shell elements. , 2D 4-noded and 8-noded quadrilateral or 3-noded and 6-noded triangular thin shell elements. , 1D 2-noded bar, beam, rod, and spring elements. , RBE2 and RBE3 elements. , 0D concentrated mass elements. , Gap elements. Using materials for solution types NLSTATIC 106 and ADVNL 601, 106 Material types that can be used in the solution type NLSTATIC 106 include: , Isotropic with or without elastic/plastic properties. , Anisotropic for geometric nonlinear only. , Hyperelastic properties that can be assigned directly to the physical properties for PLPLANE (2D elements) or PLSOLID (3D elements). Material types that can be used in the solution type ADVNL 601, 106 include: , Isotropic. , Orthotropic. , Hyperelastic properties that can be assigned directly to the physical properties for PLPLANE (2D elements) or PLSOLID (3D elements). Entering stress/strain data for solution types NLSTATIC 106 and ADVNL 601, 106 1. Create a new isotropic material. 2. In the Stress-Strain Related Properties group, select Field from the Stress-Strain (H) list. 3. From the Specify Field list, select Table Constructor . 4. Enter a value of 0,0 for the first data point. For the second point, enter a value that corresponds to the yield point. You can also define additional data points. 5. In the Isotropic Material dialog box, enter an Initial Yield Point (LIMIT 1) value. This value must match the second stress value in the stress-strain table. Defining boundary conditions for solution types NLSTATIC 106 and ADVNL 601, 106 Boundary conditions for solution types NLSTATIC 106 and ADVNL 601, 106 can be geometry-based or finite element-based. Examples include: , Displacement constraints. , All loads. Only pressure loads are updated in geometric nonlinear. , Surface-to-surface gluing. Surface-to-surface contact is supported for ADVNL 601, 106, but not for NLSTATIC 106. NLSTATIC 106的求解设置 , Large Displacements — Includes nonlinear geometry effects. , Intermediate Output — Determines if output is stored for every converged load increment, or only at the final increment for each subcase. , Number of Increments — Subdivides all subcase loads by the value entered. This can be increased if a solution has problems converging. ADVNL 601, 106的求解设置 solution control and strategy in ADVNL 601,106 are set under the Case Control tab/Strategy Parameters. Some examples are: , Analysis Control — Setting the Automatic Incrementation Scheme to ATS automatically subdivides time steps that fail to converge. , Equilibrium — Can be used to adjust the default convergence options and tolerances. Also, the line search iteration scheme can be selected here. , Contact — Controls contact options for all contact sets. 响应仿真 主要就是用于确定结构模型对于一系列载荷工况的动态或静态响应 仿真步骤 Step Summary Define the geometry, material properties, mesh, and constraints, as you would for other 1. Build the finite structural solution types. element (FE) model. Also, specify the locations of your excitations and define any static and dynamic loads. Create an NX Nastran SEMODES 103 – Response Simulation solution. 2. Create the NX Nastran solution. You can also use an SEMODES 103 solution, but it generates only the normal modes. NX Nastran generates normal modes, constraint 3. Solve the model. modes, attachment modes, and other modal information. 4. Create the After solving the model, create the Response Response Simulation solution process. Simulation. Review the mode shapes in the Post-Processing 5. Review the mode Navigator or in the Response Simulation Details shapes. View subpanel in the Simulation Navigator. 6. Define the In the Response Simulation Details View damping values for subpanel, you can add viscous and hysteretic each mode. damping. Define the type of response simulation you will perform, such as transient or frequency. The 7. Create an event. event combines the modal model and your excitation functions. Step Summary 8. Create Excitations define the loading for the response excitation simulation, such as a vehicle's tires following functions. a bump's profile. Depending on the type of response you are evaluating, the software calculates and stores the results in response functions or response results sets. , Response functions each contain one response (for example, stress at one 9. Analyze the node) as a function of time or frequency. model's dynamic You can plot these function records in the responses to the NX graphics window. excitations. , Response results sets each contain responses for multiple nodes or elements in the model for one time step or frequency. You can view response results sets as contour plots on the Post-Processing Navigator. Special boundary conditions In Response Simulation, a finite element (FE) model represents the physical model of the structure.在响应仿真中，除了你可以定义同其它的求 解器一样的约束与边界条外，还有如下的特殊的边界条件。 Type Description Enforced The location of an enforced motion excitation on the motion model. This is a location only; you define the actual location excitation load after you solve the solution. The solver generates constraint modes, equivalent attachment modes, and effective masses based on these locations. Create enforced motion locations in the Constraints container in the Simulation Navigator. Type Description Nodal Force The location of a nodal force excitation on the model. location This is a location only; you define the actual excitation after you solve the solution. The solver generates attachment modes based on these locations. Create nodal force locations in the Loads container in the Simulation Navigator. Static For Transient events, a constant load for scaling the offset load results (for example, a gravity load for use with concentrated mass elements, or a distributed wind load on the structure). Create static offset loads in the Subcase – Static Offset container in the Simulation Navigator. After you solve the solution and create an event, the Static Offset node appears in the Simulation Navigator under the event node. You can exclude the static offset results from the response evaluation by right-clicking the Static Offset node and choosing Deactivate. Stress A differential stiffness to account for the weakening stiffening of a structure due to stress. You can use this load to load pre-stress structures that are thin in one or two dimensions, such as shell or cable-like structures with small initial stiffness, and large membrane loads, such as a drum head with initial tension. The solver uses these loads to augment the stiffness in the normal mode calculations. It calculates the stress stiffness and combines it with the linear stiffness and then uses the combination of these two matrices to solve the normal modes eigenvalue problem. Create stress stiffening loads in the Subcase – Stress Stiffening container in the Simulation Navigator. Dynamic load A load you can scale after solving the modal solution. The solver generates a load set and distributed Type Description attachment modes for each dynamic load. You can then assign a scaling function when you create an excitation. Dynamic loads are necessary for applying distributed-load excitations and can also be used as static excitations in a Quasi-Static analysis event. Create dynamic loads in the Subcase – Dynamics container in the Simulation Navigator. Solution attributes for Response Simulation FRF and Transmissibility 在完成载荷与边界条及一些其它的边界条件之后就可以进行求解了。 ,频率响应函数(FRF) 用来评估一个或几个节点或单元的对于输入的单位载荷的 响应 ,传递性(transmissibilit)可以用来评估一个或几个节点对于强迫位移或速度 或加速度的响应。 Evaluate transmissibility (这是后处理中的重要一步) Transmissibility is a frequency response function (FRF) that lets you evaluate the response of one or several output nodes to an enforced motion input such as displacement, velocity, or acceleration at a selected node. Analysis events 分析类型及可获得的结果: Event type Response calculated 瞬态响应 结构在随时间变的的激励载荷下的动态响应 主要适用于比如驱车在一个车道上行驶或其它的任何 的结构在一段时间内受激励载荷的影响 频率响应 结构受一组振荡载荷的作用 由于发动机的振动或车轮的不平衡对于驾驶者的舒适 程度的影响 随机响应 The power spectral density (PSD), root mean square (RMS), and level-crossing rate (LCR) results of a structure to one or more simultaneous random excitations. Examples of random excitations include jet engine noise, a profile of a road surface, and the effects of turbulence on an airplane. The peak response of a structure to a set of 普分析 simultaneous base excitations defined by response (also called spectrum functions. shock response spectrum) 分析实例主要有:航空着陆, 核超压分析, 坠落实验, 地震分析 DDAM (Dynamic The dynamic response of a ship's components to Design Analysis shocks applied to the ship's hull, deck, or shell Method) plating mountings. You can define your proprietary shock coefficients as input to the DDAM event. You predefine these coefficients in a text file. Then you can enter a multiplier to adjust them each time you perform the response evaluation. Event type Response calculated Quasi-Static The static response of a structure to a set of simultaneous time-varying static excitations. This event type is useful if you are only interested in static results and need faster solution performance than a full dynamic solution. Excitation loads 激励载荷主要有以下几种: 首先激励载荷是一种外部载荷。比如说交通工具的轮胎撞到路面上的凸起。 power spectral density (PSD) root mean square (RMS) level-crossing rate (LCR) 可能是以下几种中的一种: , Nodal force defined by a node, a direction, and a force function. , Nodal enforced (强迫的)motion defined by a node, a direction, and a function of displacement, velocity, or acceleration. , Distributed-load excitation defined by scaling a load that you predefined in the solution (Transient, Frequency, or Random events only). , Constant velocity impact or drop impact applied to a single node (using an automatically generated haversine function). , Rotating force defined as either a general rotating force or an unbalanced rotating mass about a given axis (Frequency events only). Function tools for Response Simulation utility This utility provides useful function commands such as: , Easy creation of excitation functions, such as pulse(脉冲), random signal, and ramp(斜坡函数) functions , Displacement, velocity, and acceleration data conversion(数据转 换) , Time, frequency, SRS, and PSD data conversion , Interpolation , Envelope line , Equation combination , NX Nastran Punch file conversion for nodal results Sensors 传感器就是你在模型中定义的某个节点，你想在此节点处观察响应结果.比如传 感器可以代 加速计 的位置。 Sensors allow you to evaluate displacement, velocity, acceleration, and reaction force. Each node you select in your sensor definition generates a response function. Sensors are stored with names that reflect the node and direction in which the sensor evaluates. For example, Sensor_1_2_(99X+)_1 represents the function 2 result for Sensor_1 at node 99 in the positive X direction. Strain gages Use a strain gage to specify a nodal or elemental location on the model at which to evaluate stress or strain results in a specified direction. Strain gages define: , Location , Coordinate system for the stress or strain results , Components of the stress or strain results 在响应仿真的求解过程中也包含了模态响应的过程，而且如果模态数设置的越多，那么求解 结果会越准确。这个模态的仿真分析可以从后处理器中查看到。 在求解器中要进行如下的特殊设置 其它后处理 1. 当 然在此过程之前应先定义一个 响应函数 产生整个模型在极值点处的响应 1. Run a Response Results evaluation. 2. In the Evaluate Response Results dialog box, select Stress as the Requested Result (clear the Displacement check box). 3. Select all the elements in the model. 4. Select From XY Graph as the Method. 5. Under Point Value, click the button. 6. In the Equation Selection list, select 2_(16E_VONMTOP). 7. In the plotted elemental stress function, select the time point where stress is highest, and then click OK to generate the response results. 柔体分析 定义:在运动仿真的过程中只是根据一定的约束条件，刚性体作一定的运动，它不含有任何 的动态分析的特性，尤其是在以下情况下:显著的影响或运动的突然改变或是刚性杆件具有 中够的柔性而防碍运动的情况。 Flexible bodies workflow Advanced Simulation steps 1. Create a finite element model and NX Nastran SEMODES 103 – Flexible Body solution. 2. Mesh the flexible component and define material properties. 3. Use a 1D Connection (spider element) or other constraint elements to define the component's connection points to the mechanism. 4. Add Fixed Boundary Degrees of Freedom constraints to define connection degrees of freedom. 5. Add Free Boundary Degrees of Freedom constraints to define load degrees of freedom. 6. Solve the modal solution. A RecurDyn Rflex input (.rfi) file is generated for the flexible link. 7. Repeat steps 1–6 for each additional flexible component in the mechanism. Motion Simulation steps 1. Create a Flexible Body Dynamics motion simulation. 2. Create flexible links on the flexible components. Associate each .rfi file with each flexible link. 3. Create a Flexible Body solution and add the flexible links to the solution. 4. Solve the mechanism. 5. Run Animation to view the combined rigid body and flexible body motion. Connecting the flexible body FEM to the mechanism FEM file, you must define the points where the flexible body is connected to the motion mechanism. These connection points must be defined at the origin point of every joint, bushing, force, torque, spring, or damper motion object on the flexible body. Although you can use any element type to define these connection points, typically you will use a 1D Connection (spider element) Make sure the connection node is at a location that creates balanced loading. Defining connection and load degrees of freedom In Advanced Simulation, in the Simulation file, you must add special constraints to define the connection and load degrees of freedom for the flexible body. , At each connection node where the flexible body will be connected to the mechanism through a joint or bushing in Motion Simulation, create a Fixed Boundary Degrees of Freedom constraint to define the connection degrees of freedom. , At each connection node where a force, torque, spring, or damper will be applied to the flexible body in Motion Simulation, create a Free Boundary Degrees of Freedom constraint to define the load degrees of freedom. 求解器中的特殊设置 主要有以下两项:在输出中要选定 stress;及要设定 模态数。 1.Connect the flexible body FEM to the mechanism(1D Connection (spider element)) 2.Define connection degrees of freedom。使用 固定边界自由度。 :To ensure the correct local stiffness at the connection points, always set all DOF to On when creating Fixed Boundary Degrees of Freedom or Free Boundary Degrees of Freedom constraints in a flexible body analysis. When you created the connection recipe for each spider element, you placed the independent node at the bore center of the hole rather than at the arc center of the edge of the hole. The reason for this placement is to ensure balanced loading. 3. Solve the model You will solve the model to generate the .rfi file that contains the reduced matrices that represent the component's dynamic behavior. This file will be used later in the activity when you solve the Flexible Body solution in Motion Simulation. 4.进入运动仿真，然后改变 环境 选择 柔性体动力学 ，引入前面求解的 rfi 文件。然后将 此加入到解算之中。如果在运动仿真中还使用了驱动(函数类型)，那么也应将其加入 到解算方案中 进行求解。 5.求解完成之后，还要对 柔性体 编辑阻尼 ，一般设置其大小为 4.0