Applied Mechanics and Materials Vols. 121-126

Abstract: Studied the vibration performance of honeycomb paperboard with double cross-core, obtained vibration transmissibility curve of honeycomb paperboard with double cross-core, by the curve indicated, the vibration transmission properties of the honeycomb paperboard with double cross-core in the sinusoidal excitation ,and the packaging materials as contents when the size of the protection capacity. The results show that the shock resistance capacity of honeycomb paperboard with double cross-core is supers the single layer with the same thickness of.

Abstract: Backward extrusion process of aluminum-alloy wheel forging is analyzed by the finite element method. The influence of punch speed and forming temperature on the backward extrusion height of 6061 aluminum alloy wheel is discussed. Studies show that the backward extrusion height increases with increasing forming temperature, and with decreasing punch speed at the same deformation load. It is indicated that when the ranges of forming temperature is from 450 to 500°C and the punch speed is 0.5-1 mm/s, the aluminum alloy wheel has the optimal forming quality. The analysis and conclusions in this paper are helpful in developing the hot extrusion technology specification of 6061 aluminum alloy.

Abstract: The experimental data present that primary silicon is precipitated from eutectic and hypoeutectic Al–Si alloy melts. It attributes to solute redistribution on the chemical driving force. Si atoms are easy to segregate to form Si-Si clusters, resulting in primary silicon precipitated from hypereutectic Al–Si alloy. Another reason is that primary silicon is precipitated from solid-liquid interface front once solute concentration in the solidification front exceeds eutectic composition. Solute redistribution equations are derivate from Jackson-Chalmers equation. The third reason is that precious little impurity turn Heterogeneous Nucleation of Si atoms.

Abstract: The conductive plastic is widely used in making sensitive materials such as angular displacement sensors with high-precision. The resistive film of the sensor is formed by spraying and its quality has a close relationship with the resistance liquid’ density, spraying pressure and time, and drying temperature and time. We draw a conclusion from experiments that for the conductive plastic with carbon fillers, the optimal linearity is obtained under a pressure of 0.5-0.6Mpa in 6-8 seconds and the best abrasion resistance is obtained at a drying temperature of 175°C in 4 minutes when the liquid resistance contains 15% carbon. While for the conductive plastics with metal fillers, the optimal linearity is obtained under a pressure of 0.7-0.8Mpa in 5-6 seconds, and the best abrasion resistance is obtained at a drying temperature of 165°C in 4 minutes when the liquid resistance contains 6% metal fillers. The research results have some guiding significance in improving performance and lowering cost.

Abstract: Cutting chatter is a kind of severe vibration generating from the interaction of machine tool system and cutting process and it will seriously affect the performance of machine tool and the quality of work piece. With the rapid development towards high precision and automation of the modern manufacturing industry, the stability and monitoring of cutting process have become the hot issues in production and engineering field, lots of useful researches and explorations have been done worldwide. The research situations of stability limit prediction of machine tool cutting system and technology of chatter online monitoring are discussed, the problems and the developing trends are summarized.

Abstract: In this paper, the nonlinear mapping relationship between characteristic parameters of failures and failure types is realized by using neural network through extracting characteristic variables of failures during operation of the gear. Aiming at the problems of neutral network such as slow convergence speed and existence of local minima, the neural network is optimized and the ant colony neural network is established by using the ant colony algorithm to realize rapid and accurate determination of failure status of a gear from characteristic parameters of failures. In addition, validity of the established model is verified through experiments.

Abstract: Polyvinylidene fluoride/polyurethane (PVDF/PU) blend membranes were made via immersion precipitation process, the surface morphologies and the micro-porous structures of the blend membranes were analyzed using scanning electronic microscope (SEM) and fractal theory, the water flux change with the operation pressure of the blend membranes was investigated, and the relationship between blend membrane morphology and water flux was discussed. The results showed that, the water flux of the resulting blend membranes was increased, and the contribution of different structures to water flux was in the following order: cross-section finger-shaped porous defects > cross-section through holes > blend membrane surface pores. In addition, water flux of the blend membranes was also related to the deformability of PU.

Abstract: The method of computer simulation was adopted in researching the dynamic property of the inking system of offset press. The Matlab simulate calculation of continuous inking system was carried out by discretization. Then, the math model of the vibration characteristics of the vibrators and the dynamic response was built. The relationship between steady time vs. plate coverage, vibrator oscillation was studied deeply .It is concluded that the steady time is increased while the image coverage decreased, and in the absence of vibrator oscillation the steady time is inversely proportional to the image coverage. This relationship is disturbed in the real world by the oscillation of vibrators. It provided the foundation and theoretical support for the design and calculation of the inking system

Abstract: The ballistic properties of different thickness combinations of ceramic/UHMWPE composite armors were studied in this paper, in order to find a better ballistic property structure subject to 12.7mm bullet. Powder-gun ballistic testing system was used to carry out the normal impact tests to determine the response and the ballistic limit of these combinations of ceramic/UHMWPE composite armors subject to impact loading. Compared with the test, an explicit finite element (FE) model was built with LS-DYNA Code to simulate the impact process. The influence of different parameters on the impact behavior was considered analytically. Results show very good agreement with the experimental data.

Abstract: In order to save the manufacturing cost and solve problems of stamping, a new type of flexible blank-drawer (FBD) forming device was presented by the authors based on the principle of flexible stretch-forming. It can be used with a variety of different sizes, different shapes of stamping die which can cut the manufacturing cost and shorten the development cycle of sheet metal forming largely. Extensive numerical simulations of the process for forming saddle parts were carried out and the forming results using FBD were compared with those using traditional blank-holder (TBH). By adjusting the value of blank-drawer force, good quality of saddle parts can be attained easily. Simulation results indicate that FBD forming can solve the shortages of TBH forming, inhibit wrinkle, prevent fracture, and form parts with small springback and uniform strain. This work can provide useful guidance in plastic forming technology for sheet metal.