Contact of a Flat Spring
Let us consider a flat spring, composed of two parts. The length of the first plate is 3L , the length of the second one is 2L. The plates have the same width b and the same height h. The plates are fixed on the left side and are loaded with the force P on the opposite side (see figure). It is supposed, that the plates are not tied together. Each plate can freely move by other one (without friction).
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The finite element model with applied loads and restraints |
Let us use the following initial data: the length L is 0.05 m
, the width b is 0.05 m, the height h of the each plate is 0.005 m and the magnitude of the applied force P is 100 N.
Material properties are the Young's modulus E = 2.1E+011 Pa and Poisson's ratio ν = 0.28.
The maximal vertical displacement Δz can be calculated: Δz= 118*P*L3 / 24*E*J , where P
is the applied force, L is the length, J
is the axial moment of inertia.
J= b*h3/12,
where b is the width and h is the height of each plate.
The calculation using the above mentioned formulas gives the result: Δz = 5.6190E-004 m .
After carrying out calculations by the AutoFEM Analysis the following results are obtained:
Table 1.Parameters of the finite element mesh
Finite Element Type |
Number of Nodes |
Number of Finite Elements |
Quadratic tetrahedron |
623 |
2023 |
Table 2.The result “Displacement OZ”*
Numerical solution |
Analytical solution |
Error δ=100%*|Δz - Δz*|/|Δz| |
5.4686E-004 |
5.6190E-004 |
2.68 |
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Conclusions:
The relative error of the numerical solution compared to the analytical solution is equal to 2.84% for quadratic finite elements.
*The results of numerical tests depend on the finite element mesh and may differ slightly from those given in the table.
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