PSI - Issue 41

A.R.F. Soares et al. / Procedia Structural Integrity 41 (2022) 48–59 Soares et al. / Structural Integrity Procedia 00 (2019) 000 – 000

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Fig. 2. Parametric scheme for developing the force analyses on the specimens.

Fig. 3. Schematic representation of mixed-mode using the superposition principle.

3.2. FEM optimization

The proposed device is the result of a series of design iterations, each one accompanied by FEM analyses. All the components were designed to be manufactured from a cold work steel alloy or mould steel (40CrMnNiMo8-6-4), whose mechanical properties are: Young’s modulus ( E ) of 210 GPa, Poi sson’s ratio of (  ) of 0.30, shear modulus ( G ) of 81 GPa, yield stress (  y ) of 900 MPa, tensile strength (  u ) of 1000 MPa, and hardness of 290 to 330 HB (Fischer et al., 2010). Each component within the model was meshed using tetrahedral structural elements, and the final model contained 55544 elements and 96945 nodes. The load applied to the model was 20 kN, which is the design load (Fig. 4). The four holes in the bottom plate were constrained, representing the fixation of the device on the UTM table. In addition, as link #10 (Fig. 1) pivots in two points to transmit the load but not moment, sliding boundary conditions were applied, simulating such behaviour. A generic block representing the testing specimen was additionally placed inside the device, hence the loads are transferred through it. Once the simulations were completed, the von Mises stresses and the displacements were analysed, as shown in Fig. 5. The von Mises stress was used to calculate the safety factor (SF) of the device. In the final design, the von Mises stresses were below the material’s  y (Fig. 5), indicating that the SF was higher than one (SF=1.07). Consequently, the device will not suffer any permanent deformation at service.