VM-WB-MECH-074

VM-WB-MECH-074
Tension/Compression Only Springs

Overview

Reference:	Rao, Singiresu S. (2004). Mechanical Vibrations (4th ed.). Singapore: Prentice Hall. .
Solver(s):	Ansys Mechanical
Analysis Type(s):	Rigid Body Dynamic Spring Analysis
Element Type(s):	Solid

Test Case

This test calculates the elastic forces of both tension and compression only springs. A compression only spring uses a negative (compressive) displacement. A tension only spring uses a positive (tensile) displacement. Both spring types are analyzed in tension and compression loading. The detection of the spring state being in tension or compression is determined by the non-linear solver.

Figure 100: Schematic

Material Properties

Geometric Properties

k = 1.0e7 N/m

x₁ = 0.5 m

x₂ = -0.5 m

m = 7850 kg

L_o = 1 m

Analysis Assumptions and Modeling Notes

Hooke’s Law:

Elastic Force = Spring Constant * Displacement

F = k*x

Spring 1: Compression Only spring

Spring 2: Tension Only spring

Results Comparison

Tensile Displacement (x₁)

Results	Target	Mechanical	Error (%)
Elastic Force (N) Spring 1	0	0	0
Elastic Force (N) Spring 2	5.0e6	5.0e6	0

Compressive Displacement (x₂)

Results	Target	Mechanical	Error (%)
Elastic Force (N) Spring 1	-5.0e6	-5.0e6	0
Elastic Force (N) Spring 2	0	0	0