PSI - Issue 42

Mohamed M.A. Ammar et al. / Procedia Structural Integrity 42 (2022) 1328–1335 Mohamed Ammar / Structural Integrity Procedia 00 (2019) 000–000

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(b)

(a)

(d)

(c)

Fig. 4: Micrographs of composite samples when the plies are in di ff erent directions (i.e. (a) and (b)) and in the same directions (i.e. (c) and (d).

di ff erent fiber directions in the consecutive layers led to decreasing the maximum tensile stresses to 70 MPa and 68 MPa in the [45 o , -45 o , 45 o , -45 o ] and [0 o , 90 o , 0 o , 90 o ], respectively. This emphasizes the e ff ect of changing the fiber directions and the laminate configurations on the induced residual stresses in the lamina scale as well as the fiber matrix scale. Therefore, the composite laminate configurations could be manipulated to decrease the formation of the tensile residual stresses inside the fabricated structures.

5. Conclusions

This work studies the e ff ect of the lamina’s orientation on the induced residual stresses inside the fabricated com posite structures. The robotic fiber placement is utilized to fabricate the composite samples. Subsequently, the residual stresses are estimated and calculated through the specimen’s cross-section based on the hole-drilling technique. The samples are analysed on the micro-scale using SEM analysis. The integrity of the composite components is found