Applied Mechanics and Materials Vols. 157-158

Abstract: The objective of this research was to investigate cold work of alloy steel which was affected on scale in annealing process. Material used in the experiment was alloy steel, AISI 4140, that widely used in automotive industry and it have been annealing after cold forming operation. The experiment was conducted on four level of percentage of cold work, 0% - 30%. The annealing temperature was set up at three levels between 845– 900°C and three type of controlled atmosphere in annealing consist of normal atmosphere and reduction atmosphere with two inert gas, nitrogen and argon. The result was indicated that percentage of cold work affected to formation of scale, high percentage of cold work, more percent weight of scale. Furthermore, the controlled atmosphere in annealing with nitrogen can be producing less scale surface than reduction with argon and normal condition, respectively. Moreover, the scale was a few affected by temperature of heat treatment in annealing. High temperature could be produced more scale surface than low temperature in all percentage of cold work

Abstract: Welding process is a non-linear, multi-variable and time-varying process accompanied by many interference factors such as dust, intense arc and electromagnetism, so it is difficult to obtain accurate information reflecting the welding process status, let alone controlling the process precisely. This paper used arc sensor, sound sensor and visual sensor simultaneously to obtain different information of the pulsed-GTAW process, and SVM was used to fuse the information to predict the quality of the welding process, experiment results showed multi-sensor information fusion could predict the process more precisely. This laid the foundation for further controlling the welding quality automatically and intelligently.

Abstract: In the logistics service supply chain based on Multi-Agent system, it is a combinatorial optimization problem possessing highly complexity and dynamic uncertainty to allocate the resources of various logistics companies. Therefore, in this paper, ant colony algorithm is introduced to the Multi-Agent System, and we establish a resource allocation model based on ant colony algorithm for logistics service supply chain in view of Multi-Agent. In the model, ants are replaced by agents. At the end, the paper realizes the optimization of logistics services supply chain.

Abstract: A calculation method was developed to predict motion of supercavitation vehicles based on the computational fluid dynamics (CFD) model. Control equation of supercavitating flow and motion equations of vehicles are coupling solved through self-made software. This method can directly obtain hydrodynamic data of the vehicle and accurately predict instantaneous motion attitude and trajectory of the vehicle. The simulation results of a supercavitation vehicle motion process show that this method can predict interaction between vehicle and cavity surface and periodic tail beat phenomenon, which accord with experiment results. Furthermore, the periodic variation of vehicle attack angle, which is found in experimental studies, is also caught though simulation. This further proves that the method developed in this paper has an ability to accurately simulate motion of supercavitation vehicles underwater.

Abstract: Fatigue durability is an important attributes of cardiovascular stent. This paper develops a stent fatigue test instrument. And then a fatigue test for cardiovascular stent is carried out successfully with this stent fatigue test instrument. The test result shows that the stents tested still maintain integrity after 400 mio fatigue cycles --corresponding to about 10 years. This paper can provide the guidance for the stent design.

Abstract: The most important characteristics for service safety of complex metal structures are those describing crack initiation and growth caused by static or dynamic, variable loading. Crack initiation and growth is subject of numerous investigations by different methods. The paper shows the possibility of applying infrared thermography to the problems of fracture mechanics. The main aim of testing was to qualitative relate the temperature changes of the spacemen measured by infrared thermography with the evaluation of fatigue cracks in steel specimen. Based on the distribution of temperature on the surface of the sample, during the action of force, the spread of plastic zones and crack tip are determined. The increase of temperature produced by the plastic deformation at the crack tip has been measured by infrared camera Thermal CAM SC640, FLIR Systems. SE(B) specimens were tested in three-point bending (TPB), following the procedures of ASTM E1820, on electrical mechanical testing machine with crack tip opening displacement (CTOD) control, at room temperature. Numerical simulation of stress distribution on the same model under same condition is presented, too. The results showed that thermography is a method suitable for monitoring and prediction of crack initiation and growth, as well as critical stress in elastic and elastic-plastic deformations. Fatigue crack growth behaviour of cracked TPB specimen made of S355 J2 G3 steel using Paris relation is considered.

Abstract: In order to facilitate the users choice and the designers continuous improvements for clothing CAD softwares,the characteristics drafting with ET and Richforever were compared and analyzed through the female top basic block drafting in the paper. The results of the study show either ET or Richforever can satisfy the need drafting,give designers greater freedom to draft and is easy and simple to handle. The function of their intelligent pens is very comprehensive. The characteristics mean that the efficiency will increase and the production cycle will shorten.

Abstract: In this paper , on the platform of Adams ,the model neutral files(MNF) of the double-gear parallel driving system for the forging manipulator were created by utilizing the FEA technology，and its virtual prototype of rigid body and flexible body were established.Through defined same motion and load by step function，dynamic simulation was analyzed.Comparing the results such as angular velocity and gear meshing force of each other，studies suggest that: to treat the transmission system as rigid body can fully meet the research requirement for load balancing.

Abstract: In machine dynamics the modal analysis of tool holder-spindle assembly is carried out to verify the reasonability of spindle speed, recognize the impaction of vibration modes on machining accuracy and optimize the design of spindle. This paper presents modeling and modal analysis of tool holder-spindle assembly utilizing FEA. Bearing supports is simulated by four uniformly distributed translational spring-damper elements and the radial stiffness of bearings is calculated based on Hertz contact theory. The connection at the tool holder-spindle interface is assumed to be the rigid-connection. This study also proposes two numerical methods in the finite element analysis software ANSYS to simulate the rigid-connection. Consequently, the present modeling and analysis approach by use of FEA is feasible for analyzing tool holder-spindle assembly dynamics.

Abstract: Aiming to improve the defect mandible reconstruction operation success rate, the original mandible and fibular 3D model were modeling separately. According to the patient’s virtual reconstruction mandible 3D model, the mandible customized virtual ti-plate was designed and modeling. Through comparing the deformation simulation analysis of reconstructive mandible, the maximum deformation occurred near the mandible midline. There was little deformation at bilateral mandible ramus posterior. As the loading on the reconstructive mandible increasing, the maximum deformation near the mandible midline was increasing. According to the customized titanium plate virtual design and deformation simulation analysis of human lateral mandible defect before operation, the simulation could predict the mandible maximum deformation position after the surgery. The doctors could improve the operation precision of mandible reconstruction and probability of success significantly.