Parts
You can build the following types of parts in Template Builder:
General Parts
A general part is a rigid part that is defined by its location, orientation, mass, inertia, and center of gravity.
Note that the computed mass properties are not parametric. Your template-based product does not update the mass properties when the geometry changes (for example, if hardpoints have changed position). If you want to have the part mass re-computed based upon a part’s geometry, you must explicitly have your template-based product compute the mass properties based on the changed geometry by calculating the mass for the general part, using the Build or Adjust menus. Alternatively, you can change the mass properties to user-defined values by modifying the general part using the Build or Adjust menus.
General parts can be modeled as flexible by performing a rigid-flex body swap. Learn about flexible parts.
Creating or Modifying a General Part
In Standard Interface, to modify a general part:
1. From the Adjust menu, point to General Part, and then select Modify.
3. Select OK.
In Template Builder, to create or modify a general part:
1. From the Build menu, point to Parts, point to General Part, and then select New/Modify.
3. Select OK.
Calculating the Mass of a General Part
You can calculate the mass based on material properties (steel, aluminum, and so on) or enter a material density. The mass will be based on the volume of the associated geometry.
To calculate the mass of a general part:
1. Do one of the following:
■From the Build menu, point to Parts, point to General Part, and then select Modify.
■From create/modify dialog boxes, select 
.
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Using the General Part Wizard
You can use the general part wizard to create simple geometry. Using the general part wizard allows the Template Builder to automatically calculate mass and inertia properties. You can create either a link or an arm and choose the material properties.
To use the general part wizard:
1. From the Build menu, point to Parts, point to General Part, and then select Wizard.
3. Select OK.
Flexible Bodies
The template-based modelers incorporate all capabilities of Adams Flex, Adams ViewFlex, and Adams MaxFlex. Adams Flex accesses a finite element analysis (FEA) program's output file (either a Modal Neutral File (MNF) or Nastran database file (MASTER)). ViewFlex allows the Adams user to generate a MNF directly from the part's geometry, without needing a separate FEA. MaxFlex uses non-linear finite element solution, by accessing a Nastran Bulk Data File (BDF).
The information in an MNF or MASTER file includes:
■Geometry (locations of nodes and node connectivity)
■Nodal mass and inertia
■Mode shapes
■Generalized mass and stiffness for mode shapes
■Interface nodes
A MASTER file can also contain more than one flexible body, accessed by specifying an index number.
Adams Flex and ViewFlex use a modal flexibility method. Modal flexibility assigns a set of mode shapes (eigenvectors) to a flexible body. The principle of linear superposition is then used to combine the mode shapes at each time step to reproduce the total deformation of the flexible body. This method can be very useful in problems that are characterized by linear elasticity and moderate deflections. It does not produce correct results for geometric nonlinearity, nor are nonlinear material properties supported. For those nonlinear use cases, Adams MaxFlex is the recommended solution.
In addition to the ability to create flexible bodies at the template level, you can also integrate flexible bodies in your subsystems. Swapping rigid bodies with flexible bodies eliminates the need for multiple templates. With rigid-to-flexible swapping, flexibility becomes a property of the general part. When you integrate a flexible body into a subsystem, you must:
■Supply a file. This means that the MNF, MASTER, or BDF file should have been previously created and stored in a shared or private database.
■Swap the rigid body for a flexible body: from the Adjust menu, point to General Part, select Rigid to Flex, and then press F1 for help. Select the FEA file type, and supply the path to the file.
■Specify the connectivity. On the Swap dialog, select the Connections tab to get a list of markers that will be moved from the rigid body to the flexible body. You can specify the node(s) with which you want each marker to associate. Leaving the node field blank or specifying a node of 0 will both result in the marker moving with the "rigid body" displacement of the flexible body.
To successfully integrate a flexible body into an Adams Car model, consider these precautions:
■Use flexible bodies if component flexibility affects the dynamic behavior of your model or if you are interested in accurate deformations of the flexible body under various load conditions.
■When generating the finite element model, you should designate those nodes that will carry applied loads or constraints as special "interface" nodes. This instructs the finite element program to solve for an additional six modes (the six degrees of freedom) at those nodes. This method results in a more accurate stiffness tensor at the load/constraint locations.
■Flexible bodies defined with MNF and MASTER files use a linear combination of modal deformation shapes. Therefore geometric nonlinearity (e.g. deformation greater than roughly 10% of the characteristic length) cannot be simulated with this method. Adams MaxFlex is the recommended method for this use case.
■Consider the computational load that a flexible body representation demands. For MNF and MASTER representations, the number of nodes and elements does not affect computation time. The number of active modes, and the frequency of those modes is what drives computation time.
■Adams MaxFlex requires significantly more computer resources and simulation time than the Adams Flex modal method, because it performs a nonlinear finite element solution at every step of the dynamics analysis.
■Verify your flexible body and check the mass and inertia properties against FEA results.
■For flexible bodies represented with Adams Flex, check the natural frequencies associated with the active mode shapes. Compare to FEA results to ensure a valid representation in Adams.
About Flexible Body Damping Ratio
Dynamic system simulations are greatly complicated when the time integration must traverse a signal with very high frequency components. To achieve the desired accuracy, Adams Solver must integrate the signal with a time step short enough to capture the frequency content. Flexible bodies can contribute large amounts of high frequency content and can, therefore, be difficult to simulate.
For the Adams Flex modal method, carefully applying modal damping can help you successfully simulate a model containing flexible bodies. You can specify a single scalar damping value applied to all the modes, control the damping using a DMPSUB user-written subroutine, or accept the default nonzero damping that Adams Flex applies to all the modes.
If you do not specify the damping, Adams Flex applies the following defaults:
■1% of critical damping for all modes with frequency lower than 100 Hz.
■10% of critical damping for modes with frequency between 100 and 1000 Hz.
■100% critical damping for modes with a frequency higher than 1000 Hz.
During simulations, Adams Car displays in the Message Window the type of damping that you selected for each flexible body in the model.
We suggest you start with the default damping ratio. If simulation time is prohibitive, or your frequencies of interest are significantly different than the table above, or the undamped vibration of your flexible body at high frequencies is important, modify the damping accordingly.
In Standard Interface, to modify a flexible body:
1. If the displayed subsystem or assembly has a flexible part, from the Adjust menu, point to Flexible Body, and then select Modify.
3. Select OK.
In Template Builder, to create or modify a flexible body:
1. From the Build menu, point to Parts, point to Flexible Body, and then select New/Modify.
2. Press F1 and then follow the instructions in the dialog box help for Create/Modify Flexible Body.
3. Select OK.
In either mode, to swap a rigid body for a flexible body, do one of the following:
■From the Model Browser, right-click on the general part name, and select Make Flexible. Hit Import to use an existing MNF, MASTER, or BDF file. Hit Create New to use ViewFlex to generate a MNF.
■From the main window, right-click on the general part, and select either Make Flexible (Import) or Make Flexible (ViewFlex).
In the Standard Interface, you can also initiate a rigid-flex swap by selecting the Adjust menu, General Part, then Rigid To Flex.
Then press F1 and follow the instructions in the dialog box help.
After performing a rigid-flex swap, the part information stored in the subsystem will include a mode status table and a marker-node connectivity table. An example from a TeimOrbit subsystem is shown below. In the connectivity table, note that a marker can attach to multiple nodes. Specifying node_id = 0 results in the marker moving with the “rigid-body” displacement, and node_id = -1 results in the marker being attached to the closest node. A marker that is missing from this table altogether will be connected to the closest node. Markers that contain an expression for the node association will not be written to this table.
In the mode status table, notice the first six modes (corresponding to the six rigid-body DOF) are typically disabled.
(CONNECTIVITY)
{marker_name connectivity node_id}
'afl_aforce_i_2 ' 'keep_expr ' 47525,47526
'bxl_bushing_i_1 ' 'keep_expr ' 47523
'bxl_bushing_i_2 ' 'keep_expr ' 47524
'bxl_bushing_j_8 ' 'keep_expr ' 47526
'jxl_joint_i_2 ' 'keep_expr ' 47525
'jxl_joint_i_8 ' 'keep_expr ' 47526
'jxl_joint_j_16 ' 'keep_expr ' 47526
'original_rigid_cm' 'keep_expr ' 0
'original_rigid_im' 'keep_expr ' 0
'mal_measurement ' 'keep_expr ' -1
(MODE_STATUS)
{mode_number mode_status info:frequency}
1 'disabled' -0.00111
2 'disabled' -0.00054
3 'disabled' 0.00062
4 'disabled' 0.00107
5 'disabled' 0.00141
6 'disabled' 0.00148
7 'enabled ' 394.03495
8 'enabled ' 625.48336
9 'enabled ' 762.22747
10 'enabled ' 855.45905
11 'enabled ' 1542.35763
12 'enabled ' 1950.29796
FE Parts
Your template-based product can model structural flexibility with the use of FE Parts, without the need for a finite element analysis (FEA) program. The FE Part is a wholly Adams-native modeling object with inertia properties and is accurate for very large deformation cases (that is, geometric nonlinearity) of beam-like structures. The FE Part differs from the linear flexible body option within Adams Flex in two significant ways: 1) it has the ability to accurately represent large deformations which the linear modes approach cannot and 2) its modeling does not require an FEA-produced file like the modal neutral file (MNF). The FE Part also differs from the BEAM force element in that it possesses inertia properties, and is capable of very large deformation.
In Standard Interface, to modify an FE Part:
1. If the displayed subsystem or assembly has an FE Part, from the Adjust menu, select FE Part.
3. Select OK.
In Template Builder, to create or modify an FE Part:
1. From the Build menu, point to Parts, point to FE Part, and then select New/Modify.
3. Select OK.
Nonlinear Beams
Using a nonlinear beam offers you a quick and easy way to deliver flexibility during early design stages.
A nonlinear beam can be modeled in one of three ways:
■Rigid - A rigid nonlinear beam is a sequence of cylindrical/rectangular segments that belongs to one part. You can use rigid nonlinear beams to model links that do not have a simple straight-line shape.
■Discrete Flexible Links - Consists of one or more cylindrical/rectangular segments connected to each other at Coordinate References. The template-based product creates a separate part for each coordinate reference you specify. Each part is divided into two halves between coordinate references, with each half connected elastically by a BEAM element. You can use this type of nonlinear beam to model components such as anti-roll bars. It's important to note that each section of BEAM is linear, but by chaining multiple short BEAM elements together, you can achieve geometric nonlinearity. Material nonlinearity is not supported.
■FE Part - Consists of a single FE Part. The FE Part can be created with a node at each Coordinate Reference you specify, or with evenly distributed nodes along the centerline. You can use this type of nonlinear beam to model components such as twist-beam suspensions, which are difficult to model using other techniques.
The mass and inertia properties of a nonlinear beam are determined according to the cross-section and material type. The stiffness properties can either be automatically calculated or user-specified.
In Standard Interface, to modify a nonlinear beam:
1. From the Adjust menu, select Nonlinear Rod.
3. Select OK.
In Template Builder, to create or modify a nonlinear beam:
1. From the Build menu, point to Parts, point to Nonlinear Beam, and then select New/Modify.
2. Press F1 and then follow the instructions in the dialog box help for Create/Modify Nonlinear Beam.
3. Select OK.
Mount Parts
A mount part is a massless part that acts as an alias for another part in a separate template. You can use this alias part as you would use the real part when creating joints, springs, contacts, and so on. A mount part is fixed to ground by default. If there are matching communicators of type mount found during the assembly process, the template-based product fixes the mount part to the part specified as the value of the corresponding output communicator.
To create or modify a mount part:
1. From the Build menu, point to Parts, point to Mount, and then select New/Modify.
3. Select OK.
Switch Parts
A switch part is a massless part that enables variable topology. You can use this switch part as you would use any real part when creating joints, springs, bushings, and so on. Your template-based product has a list of real parts related to each switch part. At any time, the switch part is fixed to one and only one of the parts on the part list.
A switch part lets you explore multiple topological solutions. For example, a suspension may connect either directly to a chassis or to a subframe, depending on the subsystems active during assembly. The switch part makes these topological changes possible. Following assembly, the user may choose to remove the switch parts from the model (losing the ability to vary the topology), deactivate them (so they don't participate in the Adams analysis), or leave them active.
When you choose a new part in the Switch to Part pull-down menu, the switch part changes the part it is fixed to, and all the joints and forces acting on the switch part will act on the new part.
After assembly you may choose to remove or deactivate switch parts to omit them from the Adams analysis. The "remove" operation is irreversible, while the "deactivate" operation is reversible.
Creating or Modifying Switch Parts
In Standard Interface, to modify a switch part:
1. From the Adjust menu, select Switch Part.
3. Select OK.
In Template Builder, to create or modify a switch part:
1. From the Build menu, point to Parts, point to Switch, and then select New/Modify.
3. Select OK.
Removing/Deactivating/Restoring Switch Parts
To remove/deactivate/restore all switch parts:
1. From the Tools menu, select Remove Switch Parts.
2. Press F1 and then follow the instructions in the dialog box help for Switch & Remove Switch Parts.
3. Select OK.
Interface Parts
Interface parts are optional dummy parts that you may wish to use to connect flexible bodies to the rest of your template. They are massless parts fixed to an interface node. Other parts can then attach to the interface part rather than the flexible body directly.
In past versions of Adams, floating markers could not be created on flexible bodies. This meant that forces such as GFORCE, VFORCE, and VTORQUE could not refer to the flexible body as the J part. Interface parts were necessary in such cases. This floating marker limitation has since been removed, making interface parts obsolete.
To create or modify interface parts:
1. From the Build menu, point to Parts, point to Flexible Body, point to Interface Part, and then select New/Modify.
2. Press F1 and then follow the instructions in the dialog box help for Create/Modify Interface Part.
3. Select OK.
Removing Interface Parts
If you want to ensure that interface parts do not participate in the simulation, interface parts can be removed from an entire model or from a particular flexible body. This operation moves all relevant attachment markers from the interface part to the flexible body. If performed on a subsystem or assembly, this operation only affects the current session. That is, the next time the model is opened, the interface parts will be present. If performed on a template, the operation is permanent. The modified template can be saved to disk, and the next time the template is opened (or used by a subsystem) it will no longer contain the removed interface parts.
To remove all interface parts from a subsystem, assembly or template:
1. In Template Builder, from the Tools menu, select Remove Interface Parts.
2. In Standard Interface, from the Tools menu, select Model Reduction, then select Remove Interface Parts.
4. Select OK.