Processing math: 93%

SS-V: 5040 Residual Deformations in an Axially Loaded Plastic Bar

Test No. VNL05 Find residual deformations in a bar axially loaded beyond plasticity.

Definition

Figure 1.

Bar dimensions are 10 x 10 x 200 mm. Strain-stress curve of the bar material is defined by the power law:(1)
σ=Kεn
Where,
K
Strength coefficient.
n
Must be in the range [0,1].
n =0
Material is perfectly plastic.
n =1
Material is elastic.

The left end of the bar is clamped and the right end is loaded with force F.

The material properties are:
Properties
Value
K
530 MPa
n
0.26
Poisson's Ratio
0


Figure 2. Corresponded strain-stress curve
Note: Elasticity modulus defined by the first two points of the strain-stress curve is E=2.67324e+10 Pa.

The study was performed for the following load F values: 20000 N, 25000 N, and 30000 N

Reference Solution

One-dimensional analytical reference solution is described here.

At strain ε and stress σ , the residual strain is:(2)
εr=εεe=(σK)1nσE=(F(KA))1n(F(EA))
Where,
ε
Total strain in the bar.
εe
Elastic component of the total strain.
εr
Residual strain.
A
Bar cross-section area.
Then residual displacement at the right end of the bar.(3)
Ur=L0(nFK*A 

Results

The bar was modeled as a 3D solid. The left end of the solid was fixed and the right end loaded with axial force (Figure 3).


Figure 3.
The following table summarizes the residual deformations results.
Force F [N] SOL Reference, Residual Displacement [mm] SimSolid, Residual Displacement [mm] % Difference
20000 3.22 3.43 6.78%
25000 9.16 9.172 0.13%
30000 19.077 19.14 0.33%


Figure 4. von Mises stress distribution at load F=30000 N