Shi Yaoyao

Research on fuzzy control based flexible composite winding system

In the process of composite resin prepreg tape winding, the presence of pores or voids among the layers of composite can result in reduced strength of winding. To alleviate this problem, it is required that the composite tape winding machines be designed such that the layers of composite are evenly wound on the previous one. The paper presents a novel design of flexible winding system for composite tape winding. Based on the analysis of errors in winding process, the novel winding system eliminates winding point error and winding angle error based on the speed controlled flexible roller. This paper also presents the kinetic analysis of the novel system and its controller design. Experiments are conducted on the novel winding system. The experimental results illustrate that the novel flexible winding system has a good performance in winding accuracy.In the process of composite resin prepreg tape winding, the presence of pores or voids among the layers of composite can result in reduced strength of winding. To alleviate this problem, it is required that the composite tape winding machines be designed such that the layers of composite are evenly wound on the previous one. The paper presents a novel design of flexible winding system for composite tape winding. Based on the analysis of errors in winding process, the novel winding system eliminates winding point error and winding angle error based on the speed controlled flexible roller.This paper also presents the kinetic analysis of the novel system and its controller design. Experiments are conducted on the novel winding system. The experimental results illustrate that the novel flexible winding system has a good performance in winding accuracy.

Surface Morphology and Affected Layer in Disc-milling Grooving of Titanium Alloy

Abstract Disc-milling grooving experiment was carried out to measure milling force and temperature for titanium alloy samples. After machining, surface roughness, surface topography, residual stress, microstructure and microhardness under different milling conditions were analyzed. The results show that the surface roughness of the center on milling surface is lower than that of the edge; moreover, the surface roughness decreases with the increase of the spindle speed, but increases with the increase of depth of cut and feed speed. The residual compressive stress is produced on the machined surface and subsurface, and gradually declines to zero with increase of the depth. The microstructure of lattice tensile deformation is found along feed direction under the effect of milling force, progressing from the initial equiaxed structure to long flake lattice. The metallographic structure of plastic deformation zone changes with the temperature, transforming from the initial equiaxed microstructure to a lamellar microstructure when the temperature is up to β-phase transition temperature. The combination of mechanical and thermal loads increases the microhardness on the machined surface and subsurface