Abstract: The composite materials are widely used nowadays as major parts of structures in many industries like aerospace, marine, automobile, space vehicles and also for the repair and replacement of civil infrastructures. Stresses are vital parameters considered in the design of structures. Any irregularities in shape, materials, or the presence of cut-outs create localized stress concentration and reduce the capacity of the material to take loads. The anisotropic behaviour of composite structures also makes the analysis more complex. Shear loading often exists in the engineering practices such as in aerospace due to heavy aerodynamic loads. So in the present study the effects of different parameters like layup sequences, number of plies, proximity of cut-outs, shapes and arrangements of cut-outs under in-plane shear loading on the glass fibre reinforced polymer (GFRP) plate with multiple cut-outs are studied using ABAQUS. The results from the study show that all the parameters considered for the study affects the stress concentration considerably. The observations are analysed then and the final conclusions are presented.
Abstract: Buckling is a prominent condition of instability caused to a shell structure as a result of axial loadings. The process of buckling becomes more complex while analyzing thin walled structures like shells. Today such thin walled laminated composite shells are gaining more importance in many defense and industrial applications since they have greater structural efficiency and performance in relation to isotropic structures. Comprehensive understanding of the buckling response of shell structures is necessary to assure the integrity of these shells during their service life. The presence of defects, such as cracks, may severely compromise their buckling behavior and jeopardize the structural integrity. This work aims in conducting numerical analysis of cracked GFRP (Glass fibre-reinforced polymer) composite cylindrical shells under combined loading to study the effect of crack size on the buckling behavior of laminated composite cylindrical shells with different lay-up sequences. The numerical analyses were carried out using the finite element software, ABAQUS in order to predict the buckling behaviour of cracked laminated composite cylinders subject to different combinations of axial compression, torsion, internal pressure and external pressure from the interaction buckling curves.
Abstract: When the space vehicle re-enters the earth’s atmosphere at a tremendous speed the frictional resistance creates enormous heat which may penetrate the vehicle leading to wreckage, if not dissipated to the surrounding. In the present study, CFD analysis of the thermal field generated on the surface of the solid model of the nose cone of the space vehicle is analyzed. Various configurations of the surface contour of the nose cone are considered to mimic the real life situation. The commercial CFD tool SolidWorks Flow Simulation module was used for the analysis. Four different surface contours were considered for the analysis of the temperature generated on its surface. The results indicate that the surface contour and re-entry velocity has a decided effect on the thermal field developed due to frictional resistance. Nose cone with larger half cone angle with small bluntness ratio offers greater resistance and hence lower temperature is generated compared to small half cone angle configuration.