Issue 49

E. Abdelouahed et alii, Frattura ed Integrità Strutturale, 49 (2019) 698-713; DOI: 10.3221/IGF-ESIS.49.63 711 Figure 19 : Damage recapitulative in a) hors plans moment b) opening moment c) closing moment in elbows composite structure with effect of default types and their position under thermomechanical loaded condition. Fig. (19) presents a series of calculations made for different cases of structure, under the same levels of internal pressure and applied temperature. A summary takes place to clarify the effect of both location and quality of defect on the critical moment of each situation. The structure beneath the out-of-plane bending moment shows that the defect quality effect appears slightly in each location, which is not the case for the other two situations of bending moment (in closing and opening), where the quality effect is the same. In all three bending modes, the location has a critical time effect. This effect occurs with significant levels for the fault location near the end, which is where critical areas of tension or fiber compression in the 30° elbow occur. C ONCLUSION his work has well presented the effectiveness of the damage criterion under complex geometric and loading conditions and in composite structures of a tubular model connected by elbow in the middle. The results obtained allowed us to evaluate and compare various parameters influencing the damage of our structure to study. • The Hashin criterion technique was used to estimate the critical moment value of the composite pipeline structure under thermomechanical behavior using shell elements • Pressurized tubular composite structures can support the same loading with different deformation capabilities. • The presence of a defect aggravates the damage by its quality and is location and following the mode of bending moment applied. In the tubular structures the internal pressure opposes the ovalization during loading in bending moment. • The bending mode undergone by the elbow conditions the ovalization planes and its capacity supported by the fibers is dependent on the angle of the elbow. T