Key Engineering Materials Vol. 693

Abstract: To investigate factors affecting contact interface pressure distribution in bolted joint, a parametric model was established by ANSYS APDL language in this paper. The contact pressure distribution on bolted joint interface was obtained through interpolating and revising contact interface forces. It is observed that the position of peak interface pressure is between the edge of bolt hole and the edge of bolt head. The contact pressure linearly changes with the bolt load while the distribution trend and radius remain unchanged. When the total thickness of clamped members is fixed, the contact pressure distribution varies from concentrated to uniform with the increasing member thickness ratio, and the maximum contact radius is reached while the member thickness is equal. When one clamped member thickness is fixed, increasing the other’s thickness can also reduce the contact pressure concentration, but the effect gradually weakens. Increasing bolt diameter can slightly increase the absolute contact radius but decrease the normalized contact radius. The inclusion of a washer under the nut can slightly promote interface clamping.

Abstract: Basing on the combining of the stone carving technology and the traditional machining technology, some parts of the design of five-axis linkage machine tool has been done and the virtual prototyping of the machine tool has been finished. This paper focuses on the whole structure’s modal analysis and column’s structural optimization of the five-axis machine tool. In view of normal surface with a large length to width ratio, we can optimize the wall thickness of the column to ensure a better dynamic performance. In the process, when the wall thickness is 10mm, the result shows a reasonable modal frequency and fitting weight.

Abstract: Flexure hinges based micro-displacement structure has been widely used for micro-precision machinery, and the natural frequency characteristics analysis is one of the most important elements in the structure design. In this paper, natural frequency characteristics analysis of a micro-displacement structure with parallel flexible hinges is presented. The effects of each structure parameter to the natural frequency of the micro-displacement structure are simulation by dynamics modeling. The parameters can be divided into three categories, namely, parallel flexure hinges parameter, micro-displacement structure parameter and material parameter. Two micro-displacement structures using common materials are machined for frequency test. The test results of two micro-displacement structure verified the modeling analysis, and the natural frequency characteristics analysis in this paper can be referenced in micro-displacement structure design.

Abstract: To improve the driller design using the variable drilling speed technology, by attaching to the cam gear mechanism on the driller spindle, adding a mandatory axial vibration to the driller. The vibration of the drilling speed at a certain waveform and within the scope of a certain amplitude of periodic change, in order to achieve the purpose of reducing the radial drill cutting chatter, ensuring processing quality of hole. Based on variable ​​cutting speed technology and the use of vibration damping mechanism, a variable speed apparatus and a cam gear are attached to achieve a vibration damping, to improve hole drilling parts dimension, shape and position of the precision of the accuracy.

Abstract: This paper presents a new method for the calibration of conical thread gauges. The procedure involves scanning of conical thread profiles, extracting all the thread main parameters, reconstructing the conical thread model. The metrologies model compared to the Standard one that is established on the basis of theoretical data. Thereby, the actual state of the threads can be fully identified by means of Screwing into the threaded length, which is good for control of the thread quality

Abstract: It is essential that the back seat of a vehicle has to be designed safely and reliably and at the same time meet the ECE R17, as to reduce the back seat casualties in accidents caused by luggage impact. This paper studies a sample of back seat frame and establishes its precise CAD model. It adopts nonlinear finite element methodology to simulate the object under the ECE R17. The results reflect two problems. One is the force absorption and anti-deformation of the split seat frame is too weak; the other is the fixed connections linking the frame to the holder is not tight enough causing easy fall-off if being shocked. The test and simulation results suggest the following alterations, respectively to substitute the previous split seat frame for a one-piece seat frame as to improve the overall stiffness and anti-deformation, to adopt one-piece structure on the center support bracket and increases its thickness by 0.5mm, keep the remaining mounting bracket structure unchanged. The analyses of the improved program demonstrate its superior anti-deformation under the regulations.

Abstract: A method of optimization design of input location parameters is proposed to analyze this problem that stress suffered by arms is big in the lifting process of Scissor Lift Mechanism. On the basis of the established stress model, and through the analysis of maximum stress function in lifting process of SLM, the input location parameters are optimized. Finally, this conclusion and the feasibility of this scheme are validated by analysis of examples.

Abstract: Taking advantage of three-dimensional software Solidworks to model for solar modules and also using finite element analysis software Ansysworkbench to conduct the stress analysis and strength check of modules, to analyze the deformation of modules under certain loading conditions, to conduct load tests and defect detection (EL experiments) and to optimize encapsulation with aluminum frame combined with the factory laboratory. The results show that: the modules have no crack and other defects and their power attenuation does not exceed the specified value after the 2.0mm thickness aluminum frame was reduced to 1.7mm.

Abstract: Drum granulators are widely used in powder granulation industry, and particles’ sphericity is one of the important indexes of drum granulation quality. To improve the particle sphericity, it is necessary to study the influence of particle size and shape on particles’ motion of both attitude and trajectory in the drum. This paper presents a mixed method of the discrete element simulation, orthogonal design experiment and mathematical statistics to investigate the influencing factors of particle orientation. The study found that there is a certain effect of particle shape, size and the speed of the drum on the particle orientation. According to the range analysis, it can be concluded that the effect of the three factors on the particle orientation is in the order of particle shape > particle size > the speed of the drum. Optimum combination was observed to be particle shape, size, and the speed of the drum are homogeneous ellipsoidal particles, 3 mm and 40 rpm, respectively. The study will facilitate to optimize the granulation process parameters.

Abstract: The underwater glider is a new type of autonomous underwater vehicle driven by buoyancy. The glider hydrofoil is the key driving element of the glider, it works under complex alternative load and determines the safety of navigation of the underwater glider. This paper takes the hydrofoil as the research object, a finite element model of hydrofoil has been established and the dynamic load of hydrofoil has been calculated. Finite element model analysis was conducted to the glider hydrofoil in free and restrained states, and the preceding few orders natural frequency of the glider hydrofoil and the corresponding vibration model and the vibration amplitude in the conditions were conducted respectively. The dangerous area of the glider hydrofoil was found out, which could provide data for optimal dynamic design and dynamic modification of hydrofoil.