Advanced Materials Research Vol. 748

Abstract: Rubber bearings are used widely in small and medium-span highway bridge structure. In this paper the transient dynamics of the plate rubber bearing and the pot rubber bearing which are widely used in practical engineering is analyzed. And the fatigue life of bridge bearing is estimated using reliability theory

Abstract: Seeker, whose performance severely affects the accuracy of guidance, plays an important role in guidance, just like the eyes of missiles. To design a seeker meeting the application requirements, multiple environmental conditions have to be taken in to consideration, such as the environments of production process, experiments, transportation and launching. This paper introduces a FEM method based optimization design strategy and a case study of mechanical framework optimization design for an infrared seeker as demonstration. The result of the design example seems positive and offers a proof of the effectiveness of the proposed method.

Abstract: The crack problem of power functionally graded spherical shell with Reissners effect is studied. Based on the Reissners theory, the governing equation of power functionally graded spherical shell is given. The eigen-solution of the crack tip field is obtained by using the asymptotic expansion method. The result is similar to Williams solution for homogeneous material.

Abstract: The range of movement(ROM) of adjacent segments and the change of intervertebral disc stress after implanting artificial cervical disc are investigated. The contact problem for bio-modeling is introduced. A normal cervical spine finite element model is proposed. The bone graft and fusion between C5 and C6 and C5/6 artificial disc implantation were simulated. The range of movement on adjacent segment and the change of intervertebral disc’s stress in such two cases are analyzed. Computational results show that the model includes the ligaments, joint capsule and other soft tissue structures, which is real, fine and high accuracy. When the adjacent intervertebral ROM was increased after interbody fusion surgery, the stress of corresponding intervertebral disc was increased obviously and the stress of upper segment of nucleus pulposus and annulus fibrosus were also increased about 70% ,besides the next-bit segments was increased about 40%. There were no differences among cervical spine ROM except extension (p> 0.05) after the implantation of artificial disc, and the stress on adjacent segments was increased less than 10%. The implantation of artificial cervical disc can release the stress on adjacent segments in a certain extent, and resume cervical activities at the same time.

Abstract: As the necessary information for planning tool path, or determining the parameters of machining processes, the groove shape of impellers should be extracted exactly. A Z-map based approach is proposed to extract the groove shape of the impeller, which is formed by hub and blades in STL models. The bottom boundaries of the groove surface are computed with its Z-map models and the polygons of the groove surface are selected with the boundaries. An experimental system is implemented and some computational experiments are performed to verify the practical applicability of the approach.

Abstract: With the rapid development of the automobile industry, improving production efficiency has become a key factor to enhance competitiveness. However, during the CAE R&D process, it has a serious impact on the labor costs due to the operation repeatability, that is to say, this work pattern drastically reduces the company's production efficiency and economic benefits, that is why it is very essential to develop the CAE automatic system. In this paper, how to develop the CAE automatic system is discussed in detail firstly, and then through the linear static analysis for a rear suspension to verify the feasibility and value of the CAE automatic system.

Abstract: Surface machining is one of the key problems in aircraft part-manufacturing. This paper presents a novel approach to solve the surface segmentation issue under 3-axis machining mode with a certain processing coordinate system, according to the workability-based ridge extracting algorithm proposed here. Firstly, basic principles such as ridge point and ridge of a surface are explained in detail. Secondly, the workability-based ridge extracting algorithm is put forward to better slice the surface. Finally, the proposed workability-based ridge extracting methodology is tested on a 3D model and its performance reveals that the method described here is effective in terms of time and feasibility. The work presented here has reached a basis for feature recognition during computer aided manufacturing process when fabricating aircraft structural parts.

Abstract: The present work focuses on the historical importance of John Philoponus' criticism to Aristotles Physics as the basis of the birth of the science of modern mechanics. In the Physics commentary, written during the 6th century, Philoponus attacks a genuinely Aristotelian doctrine which states that motion must be the effect of some kind of force acting on a body, thus requiring the continuous operation of an external agent in order to obtain a uniform motion. On the contrary, according to Philoponus' theories, motion is the result of a force impressed by a mover and which exhausts itself during the motion. Although still erroneous, in this insightful theory the first step towards the concept of inertia in modern physics can be found.

Abstract: Wheel profiles in different abrasion stages are tracked and measured for locomotives SS₄. They are then matched with rail profiles in the measured wear stability period. In order to contrast the wheel profiles in different abrasion stages, multi-body dynamic software named SIMPACK is adapted to set up a complete dynamics model of locomotives. The influence of wheel profiles in different abrasion stages on the dynamic performances of locomotives is simulated and analyzed. Analysis results state that locomotives using the wheel profiles of typeII have the good stability for their line operation. Locomotives using the wheel profiles of type I have the highest critical hunting speed of 223km/h, which is 54.8% larger than those of wheel profile JM3. When locomotives pass through curve tracks, the value of derailment factor for the wheel profiles of typeII is the smallest and achieves an excellent level, which explains that the wheel profiles of typeII can obtain the good curve negotiation performance.

Abstract: Due to the rising tendency of chemical accidents, it is urgent to develop a real-time gas diffusion simulation system on computer during the emergent chemical accidents, and high computation efficiency of gas diffusion model is indispensable in the simulation system. This paper develops an efficient diffusion model based on Gaussian Puff Model and proposes a special numerical simulation method for the model. With the proposed model and the proposed method, the spatial density distribution of the gas spread can be computed rapidly and displayed visually in GIS. To validate the correctness, efficiency, reliability and flexibility of the model, two groups of simulations in different aspects (space and time) are performed respectively. The result of simulation is as well as expected, and the system based on the model will provide a reliable guarantee for rescue during emergent chemical accidents.