PSI - Issue 56

Structural Integrity Procedia (2023) 000 – 000

7

Hanane YAAGOUBI et al. / Procedia Structural Integrity 56 (2024) 33–40

39

Figure 17 Volume calculation: Stress tensor, Gauss point evaluation, Y component (J/ m 3 ).

Figure 18 Volume calculation : Stress tensor,z component

(N/m²) stresses, Z component (J/ m 3 ) After our analysis, we remark when the temperature decreases the magnitude of displacement and the stress of von Mises also decreases. In our results, the von Mises stresses and the magnitude of displacement in a polyamide 12 layer heated by a C O 2 laser was calculated using the COMSOL V5.6 software. The proposed simulation is extremely valuable as it provides a fast and accurate prediction of the stress state in construction. This modelling aims to predict the stresses in the polyamide 12 layer. The proposed thermo-mechanical simulation will be validated by experimental work in the future. This study shows that thermal stresses appear during the laser projection; in particular when the laser beam heats the surface, as known the thermal stresses are in compression (negative values) due to the thermal expansion of the upper part of the layer and during cooling, the thermal stresses become in tension (positive values) due to removal of the upper part Elham.all (2020), The normal stress component (σyy) (Fig 17) and the longitudinal stress components (σxx) is small compared to transverse (σzz) stress components; we show the numerical results of the longitudinal (σxx) and transverse transient (σzz) stresses over the surface (Fig. 16, 18), the maximum values during the time history (1us) are 5 10 8 (j/ m 3 ) for the longitudinal direction and 6 10 8 (j/ m 3 ) for the transverse direction transforming into compressive stresses at approximately 0.8 mm deep (Fig. 12). IV. Conclusion A physics-based numerical model is proposed to quickly and accurately calculation the stress state and displacement in the additively manufactured part (selective laser sintering of polyamide12, the high computational efficiency of the proposed model makes it a powerful and useful tool for the development of new materials, creation of the new designs, it also allows effective control and optimization of the process parameters to obtain a produced part with high quality. In this modelling, the state of stress is obtained by importing the thermal history as input for residual stress prediction in which in-plane residual stress distributions are obtained from the incremental plasticity and kinematic work hardening behaviour of polyamide12, in coupling with equilibrium and compatibility conditions integrated in mechanics solid module in the COMSOL Multiphysics software. As the rapid irradiation of the laser and the rather low thermal conductivity of the polyamide material, this material undergoes a high-temperature gradient. In this work, the displacement magnitude field is predicted in the polyamide 12 layer, with a calculation of von Mises stresses and different residual stresses, this thermo-mechanical simulation will be used to reduce the deformations that appeared in the final part produced by the SLS process.