Papers by Keyword: Mechanical Coupling

Abstract: The finite element modelling is a well-established technique in studies of plastic deformation. Many commercial codes, both general purpose or dedicated, implement general constitutive laws sufficient for a first level use. However, some issues need to be addressed by using specific formulations or require more advanced modelling to take into account complex behaviors. In the present contribution, an overview of the main issues that arise in the study of hot deformation processes and their theoretical and software tools available in CSM SPA is presented with their applications to industrial cases. The overview on methodologies for modelling of plastic deformation starts from the more conventional rheological laws, through the implementation of innovative rheological laws, the microstructural and mechanical coupling and tailored material characterization and concludes with the identification of criteria for the evaluation of the internal quality of the finished products, such as the porosity closure. The applications presented concern mainly the rolling of long products.

Abstract: Micromechanical silicon resonant accelerometer can easily realize high-accuracy measurement by taking the digital signal as the output. Thus, this accelerometer has become popular in the field of micromechanical accelerometer. One-mass accelerometer with differential structure has blind area in measuring, and to overcome this deficiency, a new structure without mechanical coupling is designed. This new structure can cut off coupling channels by isolating the mass, and vibration decoupling between two resonators can be achieved structurally. Furthermore, the scale factor of the designed accelerometer is as high as 295 Hz/g. This finding indicates that this accelerometer has high mechanical sensitivity, which reduces the difficulty of follow-up testing.

Abstract: The Smart-Cut technology consists in the increasing of pressure imposed by the diffusion of hydrogen ions in the silicon substrate leading to a wafer splitting. In the present work, we studied the evolution of the stress field in the crystalline lattice of silicon, the diffusion of hydrogen ions as well as the growth and coalescence of cavities. Meanwhile, we test several models and simulate these phenomena by a numerical approach, in order to compare its results to experimental observations.

Abstract: According to sensibility and output accuracy is effected by mechanical coupling of positive and negative piezoelectricity films, analysis change of vibration beam nodes which result from coupling of positive and negative piezoelectricity films. In this paper, a new mosaic method of mechanical coupling is proposed which based on structure of the vibration beam gyroscope; the numerical calculations which result from carrying out for 60mm alloyed vibration beam illustrate the sensitivity of the Vibrating-beam Piezoelectricity Gyroscope improved 6.64%. Simulation results demonstrate sensitivity is increased 6.57% and in line with the theoretical calculations.

Abstract: In this paper, an integrated 3-axis MEMS accelerometer was analyzed. Because of asymmetrical structure, z-axis sensing element, which was imbedded in the proof mass of lateral accelerometers, had large mechanical coupling. Simulation result showed that the cross talk in z-axis was as high as 64.3%. To solve the problem, a fully symmetrical structure with vertical springs was adopted in z-axis sensing element. The movement of z-axis was linear vertical displacement instead of torsional displacement. Simulation results showed there was no obvious cross talk in z-axis sensing element.

Abstract: Studies on orientation mechanisms of the auditory systems and research of bionic structures of subminiature creatures, especially of the parasitoid fly Ormia Ochracea which has a remarkable ability to detect the direction of the incident sound stimulus despite of its tiny body size, may provide preferable solutions for the miniaturization of acoustic localization structure. In this paper, the bionic acoustic sensing device are set up and taken as the research object to find feasible orientation mechanisms, and experiments on bionic acoustic sensing device are conducted after the test system has been established.

Abstract: In this paper, the CSP (compact strip production) technology was studied with the aid of elastic-plastic and thermal-mechanical coupled FEM using commercial software ABAQUS. The distribution and change of temperature, stress and strain field in rolling process were analyzed. In the view of boundary conditional influence on temperature, some factors such as thermal exchange between the work-roll and the thin slab, plastic deforming quantity of heat, cooling flux, convection and radiation heat exchange were considered during simulation. The results show contact heat conduction and deformation heat are the main factors that influence the temperature change of the thin slab. A good agreement was found between the predicted and the experimental data.

Abstract: Sound source localization is always of great value in many engineering applications. In recent years, studies on orientation mechanisms of the auditory systems and research of bionic structures of subminiature creatures, especially of the parasitoid fly Ormia Ochracea which has a remarkable ability to detect the direction of the incident sound stimulus despite of its tiny body size, may provide preferable solutions for the miniaturization of acoustic localization structure. In this paper, the bionic acoustic sensing device are set up and taken as the research object to find feasible orientation mechanisms, and the dynamics of the bionic mechanical coupled diaphragms are analyzed. These works provide the basis for the manufacture of experimental acoustic sensing device. In the last part of this paper, experiments on bionic acoustic sensing device are conducted after the test system has been established. The measured data and the analyses based on the measured data demonstrate that the modeling methods and theoretical study in this paper are correct.

Abstract: When a new torpedo car is developed, its thermo-mechanical stress must be analyzed carefully in order to guarantee its strength condition. This paper describes an investigation into the thermo mechanical behavior of the torpedo car using ANSYS software. A three-dimensional, coupling model of torpedo car has been established successfully. The analysis produces outputs such as the temperature distribution and coupling stress of this car. The influence of swell gap and refractory lining thinning are also discussed. The results indicate that the swell gap and entire thinning of refractory lining can reduce the stress remarkably, but the local thinning will increase the stress of this local zone.

Abstract: This paper studies the effect of the Columbic force on piezoelectric fracture. Bound charges emerge on the upper and lower surfaces of a permeable crack when a piezoelectric solid with the crack is subjected to far-field mechanical/electric loading. Taking into account the Columbic force between the bound charges, we obtain a non-linear equation governing the normal component of electric displacement D₂(x₁)on the crack faces. The results show that D₂(x₁)is, in general, not a constant along the crack faces and depends on the mechanical/electric loading conditions, the crack profile and the material properties outside and inside the crack. Furthermore, we examine the Columbic force under low mechanical/electric loads and then discuss the effect of the Columbic force on the fracture behaviour of piezoelectric materials.