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)
                    
                    
                     
                 
            Where, 
                    
                        - 
                                    
                                
 
                        - Strength coefficient.
 
                    
                    
                        - 
                                    
                                
 
                        - Must be in the range [0,1].
                                
                                    - 
                                                
                                            =0
 
                                    - Material is perfectly plastic.
 
                                
                                
                                    - 
                                                
                                            =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
 
                    
                    
                        - 
                                    
                                
 
                        - 530 MPa
 
                    
                    
                        - 
                                    
                                
 
                        - 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 
                        
                     and stress 
                        
                    , the residual strain is:
(2)
                    
                    
                        
                     
                 
            Where, 
                    
                        - 
                                    
                                
 
                        - Total strain in the bar.
 
                    
                    
                        - 
                                    
                                
 
                        - Elastic component of the total strain.
 
                    
                    
                        - 
                                    
                                
 
                        - Residual strain.
 
                    
                    
                        - 
                                    
                                
 
                        - Bar cross-section area.
 
                    
                
 
            Then residual displacement at the right end of the bar.
(3)
                    
                
                 
                 
        
        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