VM-LSDYNA-SOLVE-064
VM-LSDYNA-SOLVE-064
Deep Simply-Supported Beam
Overview
| Reference: | Abbassian, F., Dawswell, D. J., & Knowles, N. C. (1987). Free vibration benchmarks. NAFEMS. |
| Analysis Type(s): | Modal Analysis |
| Element Type(s): | 1D Beam Element |
| Input Files: | Link to Input Files Download Page |
Test Case
A simply-supported beam of length L = 10 m is situated along the x-axis. The beam is constrained in the x, y, z and Rx direction on the left endpoint and in the y and z direction on the right endpoint. Modal analysis is performed on the model.
| Material Properties | Geometric Properties | Loading |
|---|---|---|
|
E = 200 x 109 N/m2 ρ = 8000.0 kg/m3 ν = 0.3 |
L = 10 m | Applied a left endpoint: ux = 0 uy = 0 uz = 0 Rx = 0 Applied a right endpoint:ux = 0 uy = 0 |
Analysis Assumptions and Modeling Notes
The model is composed of a 10 m long beam with a 2 x 2 m section dimension. Boundary conditions are defined by keywords *BOUNDARY_SPC_SET.
Results Comparison
The following table compares the frequency (Hz) calculated by LS-DYNA to the published values. Excellent agreement validates the model.
| Result | Target (NAFEMS Manual) | LS-DYNA | Error (%) |
|---|---|---|---|
| MODE 1,2 | 42.650 | 42.642 | 0.019 |
| MODE 3 | 71.200 | 70.735 | 0.653 |
| MODE 4 | 125.000 | 124.968 | 0.026 |
| MODE 5,6 | 148.150 | 148.000 | 0.101 |
| MODE 7 | 213.610 | 211.769 | 0.862 |
| MODE 8,9 | 283.470 | 282.405 | 0.376 |