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In this paper a novel design approach was proposed for determining the optimal winding parameters of composite pressure vessels based on non-geodesic trajectories. With the aid of the differential theory and winding principles, the non-geodesic trajectories were derived for various tangent points. The obtained non-geodesics for composite pressure vessels were simulated using MATLAB to verify the validity of the trajectory design. The influence of the number of the tangent points and the roving bandwidth on the non-geodesic winding patterns was evaluated. The optimal number of the tangent points and the roving bandwidth were then determined while ensuring fiber stability and full coverage on the mandrel . The finite element model of the pressure vessel was established, taken variable ply thicknesses and angles along the dome meridian into account. In addition, the stress distributions of the aluminum liner and the composite overwrap were obtained and the burst pressure of the pressure vessel was predicted. The specimen of a composite pressure vessel was fabricated using the filament winder and the experimental results were consistent with the theoretically predicted ones. It is concluded that the present method is of great significance for design and manufacture of composite pressure vessels.

Ultra-high fiber tension can provide sufficient compressive stresses to retain the permanet magnets mounted on the surface of the spindle. Therefore, a filament-wound sleeve with ultra-high fiber tension is designed to provide the radial compressive stress on the permanent magnet. Based on the elasticity theory, an approach for calculating the fiber stress distributions of composite layers and the radial compressive stresses on permanent magnets under different winding tensions are presented. The maximum winding tension of carbon fibers and the radial compressive stresses of composite layers are obtained by experiments. The fiber stresses of winding layers at the end of winding process under various winding tensions are calculated using the analytical method and finite element method, respectively. The results indicate that the analytical method can accurately predict the fiber stress distribution of the sleeve at the end of winding process and the radial compressive stresses on permanent magnets. The results obtained using the analytical method and the ones using the finite element method have a good agreement. The comparison between the analytical and experimental results is within the acceptable error. Therefore, filament-wound sleeves with ultra-high fiber tensions can satisfy the design requirements of high-speed permanent magnet rotors.

In this paper a carbon fiber reinforced composite cantilever cylinder under gravity was designed using the cantilever beam theory. The finite element model of the composite cantilever cylinder was established using software ANSYS. The static and dynamic bending responses of the cantilever cylinder were investigated with the aid of the finite element method and theory of flexible multi-body dynamics. The deflection calculated using fully constraints at the root of the cantilever cylinder under gravity satisfies the design requirements. Moreover, the response curves of deflections of the cantilever cylinder with time were obtained in terms of the step motion and sinusoidal motion, respectively, using software ADAMS. The deflections of the cantilever cylinder were also evaluated for various motions. The results indicate that the maximum deflections of the cantilever cylinder for the both motion modes do not exceed the allowable design values. The present models and methods are able to provide a useful reference for design and production of carbon fiber composite cantilever cylinders.

The binding effect of fiber materials due to the winding tension during the filament winding process of arch-shaped cross sections was successfully evaluated using the Finite Element Method (FEM). The use of FEM was validated by comparing results obtained with the results from the numerical analysis of a classic cylindrical mandrel winding model. In this study, four methods were combined in the commercial finite element code ANSYS to predict the change trend of the residual stress of the layer and explore the relationship between the winding layer thickness and the winding relaxation effect. These methods include the element birth and death option, which was used to simulate the step-by-step winding process, the thermal parameter method, which produced the equivalent filament winding tension, contact analysis, which was used to carry out the transmission of radial pressure and deformation, and the restart method, which was used to simulate the procuring process. Compared with the mathematical algorithm and test of variable thickness, the results of FEM were in the range of allowable error. Therefore, these results provide a useful reference in designing the filament wound composite structures with considerably high fiber tensions.

Composite square tubes have gained increasing attention as energy absorbers due to their high specific energy absorption capacity and long stroke. One of the key important issues for producing filament-wound composite square tubes demands both windability and uniform coverage of winding patterns. Based on the analytic geometry, the spatial relation between the feed eye and the mandrel was outlined and the kinematic equations for coupling the motion of the mandrel and the feed eye were derived. Consequently, a design method for small-angle winding of composite square tubes was proposed, taking the non-slippage condition of winding trajectories into account. A periodically geodesic winding theory was presented and its winding error for various initial winding points was analyzed. The designed fiber patterns were then applied to the practical production of a composite square tube with small winding angles. The results show that the present design method for filament-wound square tubes is accurate and reliable. The obtained kinematic equations and motion laws of the feed eye and the mandrel satisfy the basic winding principle and manufacturability of filament-wound composite square tubes. The present method is able to provide a useful tool for design and production of composite square tubes.

In this paper two winding methods were applied to produce filament-wound composite elbows, which are the whole application of non-geodesics, and the application of geodesics for the torus section and non-geodesics for cylindrical end sections. The resulting winding patterns were numerically simulated for various numbers of partitions. Tsai-Wu failure indices of the composite elbows obtained using various initial winding angles were calculated and the burst pressure of the elbow was predicted using finite element method. The results reveal that the whole application of non-geodesics leads to better structural performance of the composite elbows than the partial application of non-geodesics for cylindrical end sections. The present non-geodesics-based method provides a useful reference tool for design and production of filament-wound composite elbows.