Papers by Keyword: Large Structures

Abstract: Resin Infusion process is an affordable process for developing composite structures but resin impregnate is made difficult by its large size of engineering products. This research demonstrates development of large structures such as body of a high performance automobile in a single step resin infusion process. Three different scaled down models of the car were developed according to user’s technical requirements focusing on minimal weight, air drag and aesthetics. Pro E and ANSYS were used to determine the optimal shape, geometry, size, aesthetics and strength. The digital model of exterior shape of car body was developed through coordinate measuring machine using selected model instead of Pro-E modeling due to time constraints. The digitized data was used for development of Pro-E model. The Pro-E model was scaled up to generate CAD drawings for tool development. Different stations were marked on the model and sliced virtually for development of pattern. After developing pattern, the mold was manufactured from carbon and glass / polyester composites for prototype manufacturing of the car body. The prototype manufacturing involved placement of specific number of carbon layers as perform on female side of the mold. The vacuum sucked the resin through a number of carefully selected entry ports. Multiple resin delivery ports ensured effective resin distribution and impregnation. After curing the cutting, trimming and drilling operations were carried out to finish car body to actual size. Polyacrylic wind shield was thermoformed in convection current oven according to streamlined geometry of car body. The car body was integrated with the compatible floor panels and accessories. The crumble zone shock absorber in the bumper was manufactured using successive layers of Nomex® honeycomb and PVC rigid foam to dampen the accidental shock. The successful test runs were made to qualify the car body according to user’s technical requirements.

Abstract: Finite element model updating of a Westland Lynx XZ649 helicopter tail is presented. Eigenvalue sensitivities with respect to Young’s modulus and mass density are used. Large groups based on material input data were divided to form smaller subgroups so that those parts of the model responsible for errors in the predicted eigenvalues were located. A particular new development was the use of parameter clustering based on the similarity of different columns of the sensitivity matrix. Finally the finite element model was updated successfully with regard to the lower frequency tail-bending modes.