Applied Mechanics and Materials Vols. 275-277

Abstract: In order to obtain the detonation front shape and spreading process of detonation wave, Rotating mirror multi-streak technique was used to shoot the detonation process of charge initiated from three points by high-speed photography technique. The record negative was read and these data were analyzed. The time differences of zero-time points and t-y coordinate curve were educed, and the chart of detonation wave shape was drew. The result provides a gist for warhead design. A method for analyzing and studying wave shape is offered.

Abstract: Dimension analysis is one of the important methods to study physical problems. Dynamic response of cylinder shell under impact is a pervasive problem in engineering domain. The paper took a cylinder shell as an objective to study the main factors of influence on dynamic response of cylinder shell under impact. Using theorem we obtained several different equations for describing the dynamic response of cylinder shell under different similarity conditions. The relationship of dynamic response of dimensionless independent variables versus dependent variables for cylinder shell is set up in the end.

Abstract: A composite controller is designed based on the singular perturbation model of single-link flexible manipulators. A dynamic sliding mode controller is designed for the slow subsystem, and optimal controller is designed to stabilize the fast subsystem. Numerical simulation results confirm that the proposed controller not only can perform fast and accurate tracking, but also can reduce the chattering of the sliding-mode control, and the proposed controller can suppress the tip vibration of the flexible manipulator effectively.

Abstract: The oblique impact between cylinder and ground with friction is studied. The applicability and limitation of the classical impact theory of rigid body are verified by building oblique impact between cylinder and ground of flexible model and rigid model respectively. The finite element method is used to build the flexible model of oblique impact between cylinder and ground. It is analyzed that the sliding mode of the contact point, the direction of the friction force and Newton coefficient of restitution during collision varying with different tangential velocity. Comparing the result with the classical impact rigid model, it is proved that numerous sliding modes are existent during collision. Additionally, the applicability of the rigid model is proved in unidirectional sliding mode.

Abstract: This paper presents conceptual designs for the tolerance ring in the Hard Disk Drive (HDD) in order to reduce the total deformation of the tolerance ring and decrease the installation force during the assembly process of the actuator arm, while maintaining the natural frequency within the specification range. In this research, finite element analysis was employed to compare and analyze the installation forces, total deformations of the tolerance ring and the natural frequencies of Actuator Pivot Flex Assembly (APFA). Around its cylindrical body, the tolerance ring consists of several waves which provide rigidity for the APFA assembly to resist the axial rocking motion of the actuator arm. The idea is to decrease the contact surface area between the waves and the e-block by smoothing the contact surface of the waves along the installation direction while maintaining sufficient friction to resist the axial rocking motion. The objective of this research was to minimize the total deformation and installation force. The three input variables, i.e. width, length and height of the alternating flat curve design, were analyzed together by using the engineering optimization. The decreasing of the total deformation of the tolerance ring and installation force during APFA assembly would increase the number of cycles of the reworking process which can help increase the productivity and efficiency of HDD manufacturing.

Abstract: Shipboard service environment of solid rocket motor (SRM) was monitored. Based on the monitored temperature and vibration data, the effects of temperature and low frequency vibration load on the stress and strain of SRM were analyzed by ABAQUS. It was shown by the results that the stress and strain of gain fluctuated near the initial thermal stress and strain with the low frequency vibration load. It was also found that the variations in stress and strain of the bonding interface were larger than that of the slot.

Abstract: To ensure the safe use of lifter as process equipment for fabricating and producing railway vehicles, this paper analyzes on the working conditions of lifter and makes contact nonlinear finite element analysis on various typical working conditions. Through the analysis result on static strength thereof, the parts easily subject to dangers are located, and the failure trend of parts can be prejudged by locating the weaknesses, which guides for prejudging the failures in actual production and can prevent the occurrence of accidents.

Abstract: Based on the finite rotation hypothesis, a rigid-flexible coupling dynamic model is developed. It introduces three rigid degrees of freedom with respect to classical moderate deflection beam theory. With quasi-steady theory and pre-described wake model, aerodynamic forces are tightly coupled with structural motions. Structural forces and moments are computed while equations of motions are solved. Sectional loads by three load caculation methods are examined by the analysis results of BO105 and the flight test data of the SA349/2 helicopter. Force integration method can handle vast ranges of computation cases. The predictions are relatively good except for the numerical integrating errors. Accuracy of reaction force method depends on the accuracy of response solutions and can not predict the loads at points between nodes. For the articulated rotor, force integration method shows better results than curvature method on retreating side.

Abstract: .In this paper we present the results from a combined experimental, analytical, and computational penetration program. we use an explicit transient dynamic finite element code to model the projectile under an analytical forcing load representing the target. As angle of obliquity is increased free surface effects become significant, The analytical forcing load used here derived from the spherical cavity expansion approach with modifications to account for the free surface effects during oblique penetration. Results from the simulations show the trajectory of the projectile are in good agreement with experiments.

Abstract: To ensure the safe use of vehicle lifting jack as process equipment for fabricating and producing railway vehicles, this paper analyzes on the working conditions of vehicle lifting jack and makes contact nonlinear finite element analysis on various typical working conditions. Through the analysis result on static strength thereof, the parts easily subject to dangers are located, and the failure trend of parts can be prejudged by locating the weaknesses, which guides for prejudging the failures in actual production and can prevent the occurrence of accidents.