PSI - Issue 23

Petr Kubík et al. / Procedia Structural Integrity 23 (2019) 15–20 Petr Kubík et al. / Structural Integrity Procedia 00 (2019) 000 – 000

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3

2. Experiments

Tensile tests of dog-bone and flat grooved specimens (Fig. 1) were carried out. Zwick Z020-TND with extensometer were used for testing under the displacement control. The test speed was 1 mm/min. The gauge length of the smooth specimen was 50 mm and that of the flat grooved specimen 14 mm. Specimens were manufactured from sheet aluminum alloy EN AW 6101B, which is used in switchgears. Three pieces of each specimen geometry were tested with small scatter.

Fig. 1. Dimensions of the dog-bone specimen (left) and flat grooved specimen (right). All dimensions are in mm.

3. Elasticity and plasticity The material was modelled as a homogeneous isotropic elastic – plastic continuum. The elasticity model included two characteristics: Young’s modulus of 65 GPa and Poisson’s ratio of 0.33. These were extracted from the tensile test of dog-bone specimen. The plastic behavior was described by von Mises and Kroon – Faleskog yield criteria. The yield function for von Mises plasticity model is following

f

   

(4)

y

where y  is the yield stress and  is the equivalent stress, which is defined according to von Mises as (Mises, 1913)

2 3 J

 

(5)

The yield function of Kroon – Faleskog plasticity model is

f

k    

(6)

y

where k is the yield correction function given as

a

  

  

1



0  

a

k

1  



(7)

a     

a

0