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Torsion of Truncated Hollow Spherical Elastic Body
234-240Views:138This paper deals with the torsion of a body of rotation whose shape is a truncated hollow sphere. The material of the truncated hollow sphere is isotropic, homogeneous and linearly elastic. To solve the torsion problem, the theory of torsion of shafts of varying circular cross section is used, which is introduced by Michell and Föppl. Analytical solution is given for the shearing stresses and displacements. A numerical example illustrates the application of the presented solution. The results of the presented numerical example can be used as a benchmark problem to verify the accuracy of the results computed by finite element simulations.
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On the Torsional Rigidity of Orthotropic Beams with Rectangular Cross Section
25-30Views:97The paper deals with the torsional rigidity of homogenous and orthotropic beam with rectangular cross
section. The torsional rigidity of the considered beam is defined in the framework of the Saint-Venant theory of
uniform torsion. Exact and approximate solutions are given to the determination of the torsional rigidity. The shape
of cross section is determined which gives maximum value of the torsional rigidity for a given cross-sectional area.
The dependence of torsional rigidity as a function of the ratio shear moduli of beam is also studied. -
Development of Efficient Drive Based on Self-help
147-151Views:96The efficiency and the life rating are essential characteristics of mechanical drives. The traction drives with proper geometry can avoid the geometrical slip and their efficiency can exceed that of the gear drives. The elements has hardened steel surfaces, the lubricant is rheopectic. There is no danger for thinning the oil film and consequently for connecting the asperities. The traction drives are relatively noiseless, they are applicable for increasing speed in particular. There are some problems to be solved in friction drive. This is the necessity of clamping force. A simple machine element usually make a constant clamping force, a tensioning mechanism can be too complicated. The ideal solution is a simple design which assure a clamping force that is proportional to the instantaneous external load requirements. The authors suggest a modified machine element – a helical torsion spring, an elastic one, instead of the original, rigid annular wheel – that comprises both the driving and clamping functions, and the latter one is proportional to the external load, so that the principle of self-help operates.
