VM-LSDYNA-BENCHMARK-002

VM-LSDYNA-BENCHMARK-002
Elastic Beam, Nonlinear Deflection under Cantilever Load

Overview

Reference: Chen, L. (2010). An integral approach for large deflection cantilever beams. International Journal of Non-Linear Mechanics, (45), 301-305.
Analysis Type(s): Explicit Dynamics with Workbench LS-DYNA
Element Type(s): Solid
Input FilesLink to Input Files Download Page

Test Case

A long beam with a square cross-section is fixed at one end. A cantilever load is applied to the free end. Determine the beam projective length and beam deflection at the loaded end.

Figure 233: Problem Sketch

Problem Sketch

Figure 234: Ansys Workbench Model

Ansys Workbench Model

Material PropertiesGeometric PropertiesLoading

E = 3x107 psi

ν = 0.3

L= 50 in

B = 1 in

H = 1 in

P = 2000 lbf

Analysis Assumptions and Modeling Notes

The projective length of the deformed beam (l) was found by numerical integration of ds/dy shown below, where s is the distance along the deformed beam and l is the y-value where s = L (total length of the beam).

From this process, ℓ = 41.97 in.

The beam deflection (δ) was found by numerical integration of dx/dy shown below and δ is the x-value where y = ℓ.

From this process, δ = 24.68 in.

The LS-DYNA Explicit settings were selected to minimize solution running time but ensure that the output deflection reached a steady state free from vibrations. The load application was defined over 0.3 s (force was ramped from 0 to 2000 N over 0.15 seconds then held constant for 0.15 seconds).

The Global Damping was defined to be 100.

The element used was LS-DYNA Explicit Hex 1 with an element size of 0.25 in.

Results Comparison values are reported for the Windows 11 platform.

Results Comparison

ResultsTargetWorkbench LS-DYNAError (%)
X Displacement–9.4257–9.4257–0.057
Y Displacement–26.382–26.376–0.022