In this chapter using HyperMesh
? Contact Manager for creating ABAQUS contacts
? ABAQUS one noded elements
? Create loads on FE mesh by first creating loads on geometry (surfaces, lines, points) and then mapping or re-mapping them to FE mesh
? Specify OP parameter to remove loads from *STEPs
? Reorder *STEPs
? Graphically view boundary conditions and loads in *STEPs and export only displayed *STEPs
Hands-on exercises encompass setting up two analysis procedures: the non-linear static response of a brake pad contacting a brake disc and the linear frequency response of the disc and pad system after contact. Creating the input file for this analysis using HyperMesh is broken down into two sections:
Complete the model data
Retrieve HyperMesh file containing some model and history data
Create lumped mass
Define contact between the disc and pad
Complete the history data
Apply *DLOAD to the brake pad
Create dummy *STEP to remove *DLOAD from frequency analysis *STEP
Specify analysis procedure for frequency analysis *STEP
Comments: Units used in this model are as follows:
Length
Millimeter (mm)
Time
Millisecond (ms)
Mass
Kilogram (kg)
Stress (Derived unit)
GPa
Force (Derived unit)
kN
Section 1: Complete the model data
Exercise 1.1: Retrieve HyperMesh file
Retrieve the HyperMesh binary file named BrakeDisc_Start.hm6. It contains the following ABAQUS model and history data:
· A HyperMesh component collector named Brake_Pad_Geometry. It contains surface data for the brake pad.
· Type C3D8 and C3D6 elements for the ELSETs top (brake disc) and Pad_Solid (brake pad). Both ELSETs have a *SOLID SECTION property. In HyperMesh, this translates to two component collectors named top and Pad_Solid.
· A *MATERIAL named pad_m and associated to the ELSET Pad_Solid. In HyperMesh, this translates to a material collector named pad_m.
· A 2nd *MATERIAL named disc_m and associated to the ELSET top.
· *TRANSFORM system with all nodes assigned to it
· Two partially defined *STEPs, one for the contact analysis and the other for the frequency analysis.
Retrieve HyperMesh binary file
1. Enter the files panel, select the hm file sub-panel.
2. Click retrieve… and select the file named BrakeDisc_Start.hm6.
3. Click Open and then click return to go back to the main menu.
Overview of the model
The geometry of the disc has been simplified by making it symmetrical about a plane normal to the axis. Only half of the brake disc and one brake pad is modeled. The top disc is modeled with solid elements while half the fins will be modeled with lumped masses.
Overview of the analysis
The analysis is simplified in a few ways. First, the model will be analyzed as a mechanical contact problem with C3D8 elements (regular element type) rather than as a thermo-mechanical contact problem with C3D8T elements (thermal elements). Second, the brake pad is made of a homogeneous, isotropic material with resin bonded composite properties rather than a composite material capable of resisting heat generated from friction between the rotating disc and pad. Third, rotary inertia will not be applied to the brake disc to simulate rotation of it.
The frequency analysis *STEP requires the mass matrix of the system. Therefore, *DENSITY is specified in both *MATERIALs. In HyperMesh, add *DENSITY by editing the material collector’s card image. ABAQUS ignores any properties not required for a particular analysis. Thus, for the static analysis *STEP, ABAQUS ignores the density properties. This allows you to keep a material database with as many known properties as possible without affecting ABAQUS.
Overview of one noded ABAQUS elements in HM
ABAQUS one noded elements, such as *ELEMENT, TYPE = MASS and *ELEMENT, TYPE = ROTARYI, are 1D elements in HyperMesh. Create and organize these elements into component collectors. First, create a component collector. Assign an appropriate card image to it. Since no material is needed for one noded elements, select an existing material to avoid creating an unused one. Second, edit the component’s card image to define data for the elements. Third, select the ABAQUS element type for the appropriate HyperMesh element configuration. Lastly, create the elements. The elements are automatically organized into the current component.
http://www.cadfamily.com/html/Article/Pre-processing%20for%20brake%20system%20analysis_527_1.htm
http://www.cadfamily.com/html/Article/Pre-processing%20for%20brake%20system%20analysis_527_2.htm
http://www.cadfamily.com/html/Article/Pre-processing%20for%20brake%20system%20analysis_527_3.htm
http://www.cadfamily.com/html/Article/Pre-processing%20for%20brake%20system%20analysis_527_4.htm
http://www.cadfamily.com/html/Article/Pre-processing%20for%20brake%20system%20analysis_527_5.htm
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