Advanced Materials Research Vols. 482-484

Abstract: This paper focuses on Freeform Modeling Plus exercised in clothes reverse engineering. Taking advantage of the features of Freeform, designers do modeling and designing by using “curved surface” and “clay” functions, and then make a comparison based on modeling results. The conclusion of advantages as well as disadvantages of the two functions will provide designers with effective experience and also be conductive to their expansive thinking.

Abstract: The intelligent control punch system is completely new and comprehensive technology that combines control-science, computer science, material science and metal forming theory. Although the technology originated in 1980s from America, it had focused on the spring-back of V-shaped bending. After prolonged theoretical and experimental research, the research has been expanded to the axis-symmetric part and non-axis symmetric part. A completely mechanical model of the metal sheet punch is built.

Abstract: The cotton stalk bast fibers are a new kind of natural cellulose fibers, which have the similar properties as the flax fibers. Polypropylene (PP) is a type of matrix material and commonly used in composites. The cotton stalk bast fibers as reinforced materials and PP as matrix were used to make a new kind of composite in the experiment. The composites were prepared by mixing, molding and cold forming. Orthogonal experiment table including mass fraction of fibers, molding temperature, molding pressure and molding time was devised. Then the flexural strength, tensile strength and impact strength were tested and the analysis of range was done. The optimal processing condition was obtained as follows: mass fraction of fibers was 30%, molding temperature was 190°C, molding pressure was 12MPa and molding time was 480s. The result showed that the cotton stalk bast fibers reinforced PP composites had good mechanical properties.

Abstract: Fe-Al2O3-TiC composite were fabricated by pressureless Ti-activated reactive melt infiltration. In this paper, a kind of Al2O3-Ti porous skeleton was prepared to be infiltrated with Fe-2Cr-3C alloy under vacuum. The microstructure and component analysis was investigated by scanning electron microscopy (SEM) and X-ray diffraction analysis (XRD). Subsequently, the wear testing was conducted to investigate the wear resistance of the Fe-Al2O3-TiC composites. The result show that the Fe-2Cr-3C alloy melt can full infiltrate the two kinds of Al2O3-Ti porous skeleton at 1390°C for 2 h. In the Fe-Al2O3-TiC composite, the coarse Al2O3 particles was surrounded by the TiC layer, which was generated by the Ti-C in-situ reaction in the infiltration process. The abrasive wear resistance of Fe-Al2O3-TiC composite is better than that of the wear resistant cast iron commonly used in industry.

Abstract: Generally speaking, the human biomechanical systems can be classified into two main groups: open-loop and closed-loop systems. In this investigation, the nonlinear recursive formulation is developed for the kinematic analysis of human biomechanical systems. The nonlinear generalized Newton-Euler equations are developed for flexible bodies that undergo large translational and rotational displacements. These equations are formulated in terms of a set of time invariant scalars, vectors and matrices that depend on the spatial coordinates as well as the assumed displacement fields, and these time invariant quantities represent the dynamic coupling between the rigid body motion and elastic deformation. The formulation to solve equations of motion for human biomechanical systems consisting of interconnected rigid and flexible bodies is presented in this paper.

Abstract: It is better for a firm to make his operational and financial decisions integrated than separately, especially when he faces financial constraints. This paper tries to find out how a firm makes his optimal inventory decision under trade credit, which bridges financial and operation decision as an integrated part of goods exchange, and is an important short-term finance. Following the method developed by Li et al. (2005) and Hu et al. (2010), this paper derives a myopic policy for a firm who orders from his same supplier repeated in an infinite setting. The optimal decision for each period is related to his demand’s density function, cumulative probability distribution function. And there are several directions for further study.

Abstract: Markovian jump systems are often used to model occurrence of failures and repairs in manufacturing systems. This note concerns the state estimation problem for a class of Markovian jump systems, where the Markovian jump only occurs in some short time intervals. For this class of Markovian jump systems, the boundness of estimation error deserves our investigation. By introducing the concepts of finite-time stochastic stability, an observer ensuring the estimation error bounded in a prescribed boundary is constructed and the result is extended to γ-disturbance attenuation case. A design algorithm is proposed when some parameter optimization is involved. Numerical design examples are given to illustrate the effectiveness of our results.

Abstract: Porous UHMWPE with different character were prepared by hot press molding in Metallographic Sample Mounting. Friction and wear loss of porous UHMWPE samples were studied under different loads and lubricant on an improved tribological tester. The friction coefficient and wear loss of samples with porosity of 5.44% are lower than that of samples with porosity of 10.17%, which attribute to the better porous structure and extrusion effect of lubricant in testing. Among the increasing of loads, friction and wear loss of porous samples are enhance rapidly. It is also found that the thickness of porous layer has little effect on the tribological properties of porous UHMWPE.

Abstract: To obtain fatigue design data of the CL50A steel for meeting best fatigue reliability , The fatigue tests were carried out for the CL50A steel, the fatigue life of the steel were tested using the grouping method at the three stress levels. Using probability method, S-N curve equation and P-S-N curve equation of the steel were calculated , the estimation equation of P-S-N curve with any reliability was worked out, the theoretical basis were put up for developing design standards and safety evaluation of the steel.

Abstract: The polyorganosiloxane superhydrophobic film was fabricated via a sol-gel process followed by nano-silica(SiO₂) sol and new organo-siloxane reagent 1,1,1,3,5,5,5-heptamethyl-3-[2-(trimethoxysilyl)-ethyl]-tri-siloxane(in brief as HPTETOs), the chemical structure of the polyorganosiloxane superhydrophobic were described by Fourier transform infrared spectroscopy (FT-IR), the superhydrophobic property of the treated sample was measured by contact angle (CA) measurements. It revealed that nano-silica and polyorganosiloxane formed 3D hydrophobic groups on the film; the film has turned its wetting property from hydrophilic to superhydrophobic with water contact angle of 143.7°.