Advanced Materials Research Vol. 819

Abstract: This article researches and discusses the current situation of the modern forest fire helmet. It focuses on the problems and difficulties in the modern forest fire helmet design and analyses them. With the concept of user-friendly design, this article advances the user-friendly design principles in modern forest fire helmet design.

Abstract: Simulation study of the failure of gearbox system using virtual prototype technology and analysis of its vibration signal is a foreword topic in recent years. This paper established a rigid-flexible coupling model of gearbox system using SolidWorks, ANSYS and ADAMS. Then, make simulation under the following three conditions: normal, gear fault and bearing outer ring fault. Next, make time domain and frequency domain analysis of the simulated fault signal using MATLAB. Simulation results are consistent with gear vibration mechanism and signal modulation theory, which verified correctness and feasibility of virtual prototype technology in gearbox fault simulation. Lay foundation for gearbox fault diagnosis.

Abstract: This paper presents a complete coverage path planning method, which combines local space coverage with global motion planning. It is realized by modeling mobile robot environment based on Boustrophedon cell decomposition method; and according to the characteristics of regional environment model, the connectivity of the traversing space is represented by a complete weighted connected matrix. Then Genetic algorithm (GA) is used to optimize the subspace traversal distance to obtain the shortest global traversal sequence of mobile robot.

Abstract: This paper proposes an analytical approach to study self-synchronous motion and stabilizing conditions of a novel vibrating mechanism excited by two unbalanced rotors. This approach begins with utilizing Lagrange equation to establish differential motion equations of the system, and then obtains the dimensionless coupled equation of the unbalanced rotors with a modified average small parameter method. The zero solutions of dimensionless coupled equations are used to achieve the condition to implement self-synchronization of the vibrating system, and finally the Routh-Hurwitz criterion is used to derive the conditions of self-synchronous motion stability.

Abstract: The structure of a precision high speed spindle system is described. The shaft and bearing finite element models of the spindle system are constructed by using the Timoshenko beam element and the spring-damper unit. The static mechanical properties of spindle system and modal analysis are studied with different spring element arrangement forms. The results showed that the rotary speed designed was far lower than the critical rotary speed which matched with the low-order modal natural frequency of the spindle,so resonance vibration could be effectively avoided.

Abstract: The U-Shaped layout and function of production system is studied, the purpose is showing how the layouts and their main function influence each other, thus to provide enlightenments and references to improve the design of the production system layout. The simple automatic arrangement system is presented based on Plant Simulation software and focused on an equipment layout problem. The automatic layout system is an automatic layout system of workshop layout according to data; adopt the method of simulation modeling combined with optimization of the workshop layout. According to the different optimization objectives, the user can get a different optimal solution. Through simulation, we can get the default layout of the carrying amount, size and arrangement, combined with the enterprise's actual situation. The appropriate adjustments and production efficiency of production workshop are improved, and the operation time of manual modeling is shortened.

Abstract: In order to obtain better speed and high accuracy, real-time curve fitting and fitting processing at transition points are often necessary when machining complex contours. Based on the quadratic trigonometric Bézier curve, a new algorithm is presented to realize curve fitting only between transition segments. This method ensures the machining precision and increases the maximum allowable speed at the transition points. Simulation and experiment results show that the transition velocity changes smoothly and steadily as well as the processing efficiency is promoted.

Abstract: This text introduces the compiling research and realization of 3D cutter radius compensation based on PMAC in Five-Axis NC Machines. First, the importance of 3D cutter radius compensation to machining programming of complicated curved surface will be talked about. Then we will present the theory and accomplishment of this function. Finally, based on the train of thought, an experiment will be done on Five-Axis NC Machines. As can be seen from the result, the method, simple and right, can manufacture components with multiple-axis tandem that satisfy complicated curve accuracy class.

Abstract: Nonlinear liquid sloshing problems in a vertically excited tank are numerically simulated by using a finite difference method. First, the irregular liquid domain is mapped onto a rectangular area by σ-transformation. Then, in the process of time iteration, the free surface is forecasted to estimate the boundary of the next time layer; and some nonlinear terms are approximated to derive linear equations. Free surface elevation and sloshing forces in the vertical sloshing process can be calculated precisely by this method.

Abstract: For some product development processes, reverse engineering (RE) allows to generate surface models by using the coordinate measuring machine (CMM) scanning technique, for this methodology permits to manufacture different tools in a short development period. A case study on a boring bar with complex surface is present for a brief overview of RE and provide benefits to improve the efficiency of designing and production processes. In order to guarantee the precision of the boring bar model, two methods of software Imageware for rule surface reconstruction and NURBS fitting are used. According to compare experimental modal data with simulation modal data, verified the viability of rapid reverse modeling for damping boring bar.