Applied Mechanics and Materials Vols. 373-375

Abstract: Tailor welded blanks stamping forming technology of automotive panels has been widely used in the lightweight of automobile. The simulation research on forming and spring-back of tailor welded blank U-shaped parts was done to analyze the influence of various parameters on the spring-back and find a way to improve forming properties of tailor welded blank U-shaped parts. The optimal analysis method of combining numerical simulation with experiment was adopted to explore the influence of compensation factor on the forming precision. Finally, a reasonable initial iteration compensation factor was found to compensate the mould surface directly. Aiming at forming characteristics of tailor-welded blanks, a segmented compensation method was proposed and used on the U-shaped parts which can improve the precision of components effectively.

Abstract: A wide range of functional ceramics, a wide range of uses. It is the electronic information, integrated circuits, mobile communications, energy.An important foundation of modern high-tech fields of technology and national defense and other materials.This paper analyzes the different functions of the Nano, foam, smart, and biological status and application of new ceramic materials.And functional ceramics application of the main obstacles from the two aspects of price and reliability. Elaborated with the modern development of new technologies, functional ceramics and their applications are toward the high reliability, miniaturization, film, fine, multi-functional, intelligent, integrated, high performance, high functionality and composite structure direction.

Abstract: In this paper, compression behavior and energy absorption of aluminum alloy AA7005 tubes in T6 are investigated both experimentally and numerically. True stress-plastic strain curves from the tensile test are used in the static simulation of AA7005 tubes. The results from the experimental compression of AA7005 tubes are compared with the static simulation using LS-Dyna. The peak loads and energy absorption values between experimental compression results and numeral simulation are found to be in good agreement.

Abstract: Ultrasonic machining is a non-conventional machining process. Ultrasonic machining offers an effective alternative for ultra precision machining of hard and brittle materials due to its unique characteristics. This paper did a comprehensive analysis on ultrasonic machining mechanism in theory. The experiment compared this ultrasonic machining process with the common machining process in surface quality is done and the experimental result show that the smooth high quality surface can be obtained under ultrasonic machining.

Abstract: The corrosion is an important problem for the service safety of oil and gas pipeline. This research focuses. This paper proposed a new prediction algorithm on corrosion prediction of gathering gas pipeline, which combined modified Support Vector Machine (SVM) with unequal interval model. Firstly, grey prediction method with unequal interval model was used to pretreatment original data because there is unequal interval problem in actual collected data of pipeline. Secondly, improved Support Vector Regression (SVR) based on Genetic Algorithm (GA) and Particle Swarm Optimization (PSO) has been proposed to resolve parameters selection problem for SVR. Finally, the corrosion prediction model of gas pipeline has been proposed which combined improved SVR and unequal interval grey prediction method. The experiment results show this algorithm could increase precision of the pipeline corrosion prediction compared with the traditional SVM. This research provides reliable basis for in-service pipeline life prediction and confirming inspecting cycle.

Abstract: Due to the emergence of more and more composite armors, research related with equivalent target has practical application background. Composite armor with different physical properties between the layers weakens jet penetration effectively. If the equivalence relations between composite target and homogeneous one can be established, homogeneous target with a certain thickness takes the place of composite plates, the test cost will be slashed. After the principle of equivalent target and research methods to be introduced in brief, the jet penetration composite target for energy consumption and the jet penetration composite target depth research have been explored, the establishment about the equivalent target method of the armor-piercing projectile penetration composite armor is proposed.

Abstract: The effect of machined workpiece surface topography and surface integrity were studied. Modifications of surface layers after mechanical surface treatments were also reviewed. Conflict ideas exist in publications about which parameters can better define fatigue endurance. The traditional one was Arithmetic Average Roughness, although deepest surface feature and the square root of the defect area were proposed. The combinations of these factors including high temperature, metallurgical alternations and plastic deformations, rather than the residual stress alone affect surface topography and surface integrity. They should be examined carefully in order to gain a better understanding of fatigue.

Abstract: It is difficult to give shapes for tapered wire-pole with square cross-section in conventional plastic working process. A new dieless drawing method for making wire-pole has been developed. Through the dieless drawing theoretical study and experimental analysis of the wire-pole, a new wire-pole dieless drawing process is developed. The methods to ascertain key technique parameter are given out and the drawing velocity model is established. The experimental study shows that the dieless drawing technique is reasonable novel, the equipment is simple and one dieless drawing production procedure can replaces complete forming procedure in the general for tapered wire-pole dieless forming, which completes the deformation heat treatment, enhances the product’s overall performance simultaneously and has the practical value.

Abstract: The relation between temperature rise of bit and drilling parameters in drilling lunar soil simulant is studied in this paper through experimentation. Since it is difficult to measure the temperature of bit in the drilling process, fiber Bragg grating temperature measuring system is developed. Then, drilling experiments were carried out in normal and-30°C low temperature lunar soil simulant. This research showed a clear correlation between temperature rise of bit, rotational speed and torque in drilling process under specific lunar soil conditions. And the relations in drilling the two lunar soil simulants have similar patterns.

Abstract: Work hardening is an important index for the evaluation of the machined surface quality in high-speed milling. The morphology of work hardening can be visually observed by the metallographic pictures of high-speed milling gained from the scanning electron microscope which includes the lattice distortion and cracks etc. Forming mechanism of lattice distortion and micro crack of micro morphology under the workpiece surface is analyzed according to the dislocation theory; meanwhile, the effects on surface quality of the microstructure of the work hardening layer are discussed, which have important guiding significances on improving the surface quality and prolonging the service life of the parts.