VM275
VM275
Mode Lock-in and Friction Induced Vibrations of a Pin-Disc
Model
Overview
| Reference: | Allgaier, R., Gaul, L., Keiper, W., Willner, K., Mode Lock-In and Friction Modeling, Computational Methods in Contact Mechanics IV, ed. By L. Gaul and C.A. Brebbia, WIT Press, Southampton (1999), pg 35-47. |
| Analysis Type(s): | |
| Element Type(s): | |
| Input Listing: | vm275.dat |
Test Case
A brake squeal analysis is performed on a pin-disc model using three different procedures to highlight the mode coupling phenomenon caused by friction induced vibrations. The unstable frequency is obtained in each procedure using the unsymmetric eigensolver (MODOPT,UNSYM) and compared against the target value of the reference.
| Material Properties | Geometric Properties | Loading |
|---|---|---|
E = 70000 N/mm2 ν = 0.33 μ (coefficient of friction) = 0.152 ρ = 2.7e-09 kg/mm3 | Disc outer diameter = 358 mm Disc inner diameter = 8 mm Disc thickness = 25 mm Pin length = 149 mm Pin width = 10 mm Pin height = 10 mm | Displacement at the free end of the pin = 0.1 mm Rotational velocity (CMROTATE command) = 2.0 rad/sec |
Analysis Assumptions and Modeling Notes
The disc-pin is modeled with an aluminum material model and meshed with SOLID186 elements. The inner radius of the disc is constrained along all directions. The pin is clamped at one end and in contact with the disc at the other end at an angle of 4 degrees inclination. A standard frictional contact pair with CONTA175 and TARGE170 elements is used to model the contact region.
The unsymmetric full Newton-Raphson option is used to solve the modal analysis for all three procedures. For full non-linear perturbed modal analysis and partial non-linear perturbed modal analysis, the pre-stress load is the displacement load applied on the free end of the pin to bring both the pin and disc components into contact. The CMROTATE command is used to rotate the nodes of the disc and to generate sliding frictional contact between the disc and pin. The pin length is adjusted so that the third bending mode of the disc (2246Hz) and second bending mode of the pin (2279Hz) can couple to produce unstable squealing modes.