دانلود رایگان مقاله مدل سازی آسیب رشته فیبر کربن / لوله کامپوزیت فرسودگی رشته اپوکسی

Abstract

The focus of this study is the development of a computational model with damage to predict failure of carbon fiber/epoxy filament wound composite tubes under radial compressive loading. Numerical analysis is performed via Finite Element Method (FEM) with a damage model written as a UMAT (User Material Subroutine) and linked to commercial software. The experimental analysis carried out followed ASTM D2412-11, where the specimen is parallel-loaded by two steel-based plates. Three stacking sequences have been evaluated. Both numerical and experimental results show that the presence of hoop layers at inner and outer layers plus ±75° non-geodesic layers gives maximum compressive load to the composite tube, since the reinforcement is wound closer to the loading direction. Moreover, failure modes are predominantly delaminations, which are confirmed via numerical analyses through high in-plane shear stresses levels, and via experimental analyses through stereoscopic micrographs.

5. Conclusions

The focus of this study was the development of a computational model with damage to simulate the radial compressive behavior of filament wound composite tubes with different stacking sequences. The tubes started concentrating stress at the outermost layers due to their contact with the device loading plates and damage propagated from the contact areas. As expected, the tubes reduced in diameter in the vertical direction, and expanded in the horizontal direction, generating an elliptical deformed shape. The computational model has accurately predicted both load and deflection as compared to the experimental results. The stacking sequence strongly affected maximum load supported by the composite tubes, and the tube with more hoop layers as the outer layers of the laminate and with non-geodesic layers wound at ±75
showed better structural response. Different winding patterns for the laminas in the same laminate influenced compressive strength due to fiber inter-crossing at different positions. Finally, delaminations were the main failure mode for all investigated tubes, showing that wound composite tubes designed to withstand radial compressive loading need to be manufactured with hoop layers as inner and outer layers, along with ±75
nongeodesic layers. This type of stacking sequence yields maximum compressive load, since the reinforcement is wound closer to the loading direction.