The multi-scale modeling of ion-solid interactions presented can lead to a fundamentally new approach for understanding temperature evolution and damage formation. A coupling of the Monte Carlo code, SRIM, to a C FEM heat transfer code was performed, enabling a link between the damage cascade event to the subsequent heat transfer. Modeling results indicate that for 1 MeV Ni ion irradiation in Ni52.5Nb10Zr15Ti15Pt7.5, the heat transfer rate is too large for direct crystallization. Although the damage cascade induces a peak temperature of 5300 K, within 6 picoseconds the temperature is below the glass transition temperature. This result implies that there is a cooling rate of 10^14 K/s, which is much greater than the critical cooling rate for this material. Ion irradiation was performed to compare modeling with experiment. No evidence of direct crystallization is observed under TEM. Nanocrystals are formed as a consequence of series of multistage phase transitions. This provides evidence that the energy dissipation occurs too quickly for direct crystallization, as crystals are found in regions having undergone substantial compositional changes. A host of conventional electron microscopy methods were employed to characterize the structural changes induced by 1 MeV Ni ion irradiation in Ni52.5Nb10Zr15Ti15Pt7.5 and identify the phases that form, Ni3Nb, Ni3Ti and Ni3Zr. Scanning TEM analysis revealed Pt segregation near crystal regions due to irradiation. Due to a lack of Pt crystal phases observed and high concentrations of Pt in crystal regions it is postulated that Pt is substituting for Ni to form (Ni,Pt)3Nb and (Ni,Pt)3Ti.

A further understanding of colloidal mixture behavior under applied electric fields would greatly benefit the design of smart material systems such as electrorheological fluidic devices and microfluidic reconfigurable antennas. This thesis presents a finite element analysis of colloidal mixture electrokinetic behavior. Computations of particle forces as a function of applied frequency and particle shape were performed. An effective medium property method was also studied. Fluidic and electric forces were obtained with various applied excitation frequencies throughout three locations in a coplanar microelectrode domain. This domain consists of two 50 nanometers thick gold electrodes separated by a 30 micrometers gap. The three locations are 1.2 micrometers, 40 micrometers, and 90 micrometers from the gap center. Total force vectors were computed by integrating Maxwell and Cauchy stress tensors to determine whether the particles are pushed toward or away from the electrode gap at frequencies of 10 Hz, 1 kHz, and 100 kHz. It was determined that particles were pushed outside the gap at median frequencies of 1kHz (indicating ac electroosmotic force domination) and began to be pushed back toward the gap at higher frequencies of 100 kHz (indicating dielectrophoretic force intensification). Particle shape effects were examined by calculating the electrical interparticle force between two particles at various incidences with respect to a uniform electric field. Particle attraction occurs when the line between the particle centers is aligned with the electric field; repulsion occurs when this center line is perpendicular. The incidence angle at which the particles switch from attraction to repulsion is defined as θcr. The aspect ratio and particle edge separation distances used in this study were 1, 5,12.92 and 0.25 micrometers, 0.50 micrometers, 2.0 micrometers, respectively. The results indicate that higher aspect ratio particles tend to have smaller θcr values and larger interparticle force magnitudes for given separation distances. Finally, effective dielectric constant simulations utilizing periodic crystalline arrangements of colloidal structure were performed. The results show good agreement with the Maxwell Garnett mixing rule at volume fractions above 30 percent. Less canonical structures of cubic particles were also modeled.

The tube hydroforming (THF) technology has been widely used in manufacturing the lightweight and high strength components. The success of THF is largely dependent on the selection of the loading paths: internal pressure vs. time and axial feeding vs. time. The Finite element method is used to simulate the forming result of different loading paths and reduce the cost of die-testing. T-shape tube hydroforming is investigated adaptive simulation by combining FEM code LS-DYNA with fuzzy logic controller subroutine is proposed. During the simulation process, subroutines can adjust the loading paths according to the values of the minimum tube thickness and its variance. Then, the purpose of better thickness distribution of the formed tube at the side branch is achieved. Comparing with other linear loading paths, this adaptive control method got better results. In experiments, the validity of LS-DYNA applied in THF process is verified and the experimental results by adaptive simulation are better than those by the linear loading paths.

While evaluating the depth of corrosive defect of the pipe through Remote Field Eddy Current (RFEC) Testing technology, the critical principle of the process is to use the interaction of the magnetic field. Generally, exciter coils in the low-frequency alternating current and detector coils can generate the magnetic field. The signal curve can be transformed by receiving and plotting the induction voltage of detector coils. In addition, the signal curve can be used to identify the existence and the depth of corrosive defect from the shape and angle of the curve. Thus, the structure of the detector has a great influence on the exactitude of the testing. However, in the real experiment, RFEC probe is covered by shell and hard to disassemble. Thus, few people doing the research to analyze the structure of the RFEC probes. This research is based on two-dimensional axial-symmetry models and using Finite Element Method to simulate different structures or designs, such as the distance between exciter coils and detector coils, the amplitude and frequency of current in exciter coils, and even the material and size of shield. The simulation results show the influences of changing these important characteristics. Therefore, with these scenarios, the RFEC testing technology can be understood more completely and be improved the accuracy and reliability of the experiment by optimizing the sensibility of the RFEC probe.

Eddy current testing is a non-destructive testing method that has usually used for examination of carbon steel tubes. By using a high frequency electromagnetic field on the exciting probe, it is easy to figure out the impedance variation of the coil on impedance plane, and estimate the crack depth by measuring the angle of curve. However, different kind of tubes and electromagnetic properties resulted in different testing. The purpose of this study is to create the two dimensional axial symmetry model of eddy current testing by finite element software package FEMLAB. And it is easy to estimate the crack depth by figuring the impedance plane and evaluation curves by MATLAB. Furthermore, the research analyzed the variation of curves and angles on an impedance plane and tried to reduce testing errors. Over all, the analysis of some influence factors of eddy current testing in the present study not only provides a standard of estimating crack depth more accurately, but also reduces the evaluation errors.

The tube hydro-forming (THF) is an innovative manufacturing process which is used to manufacture many industrial components widely. The success of THF is largely dependent on the selection of the loading paths: internal pressure versus time, axial feeding versus time and counter punch (CP) versus time. The finite element analysis is used to simulate the forming result of different loading paths and reduce the cost of die-testing. This paper presents the forming of T-branches and T-branches components with CP. These paper has developed an adaptive simulation algorithm by combining FEM code LS-DYNA 3D with controller subroutine to get ideal bulging height and uniform thickness of the formed tube with multi-stages. Discuss influence under different parameters of process. The results are compared with experimental results to validate accuracy by this adaptive control methods.

This research investigates the influence of the reacting force which suffered from the handle of a hammer to strike an object. To achieve the study purpose, an impulse on the hammer face in a very short time was investigated. The researcher used computer-aided design software Solidworks to set up the hammer model and he used finite element software LS-DYNA to analysis the dynamic problem of the hammer by impulse loading. This study aims to find out the reaction force at the gripping position of different shape of cross-section, length, gripping position and angle of the handle and compares the results along x, y, and z axis respectively. After summing up an optimum handle shape and gripping position, users can operate the tool easily. The optimum also reduces the probability of musculoskeletal disorders. It is expected the study findings can not only provide some reliable data for the reference in hammer manufactures but also make a breakthrough in computing aided engineering.

This study is the method of using the mechanical type to cut the substrate of the glass , under the circumstances that the glass surface is cut directly, probably produced 10¡ã20% of the depth of crack that is the thickness of glass, and then pulled the glass and split by mechanical stress , use the ANSYS and finite element method carry on relevant research and compare, survey the perfect cutting parameter to increase the yield in the future. This study is in order to find out the surface fracture stress distribution status after cutting and take advantage with the finite element method ,and compare with the result of median crack when glass substrate after cutting .It discuss with change parameter of the cutting pressure and Cutting depth ,than to compare with finite element method, it regard as discussing the quality after cutting to reduce the risk of surface defect.

In this work we apply the finite element method to analyze the wave transmission property of solid/fluid composite medium, phononic crystal. The sound attenuation spectrum is obtained to show the forbidden bands of the band gap. First, we construct the finite element model for a two-dimensional phononic crystal, studied by Sánchez-Pérez etc. with PWE and experimentally, constituted of a rectangular array of parallel circular stainless steel cylinders in air. It has demonstrated that our simulation work was feasible; then, we performed the experimental measurements and simulations by using the narrow and wide frequencies. The results show agreement between the experiments and the simulations. We also simulated the crystal samples of filling fraction 5 % and 10 % for square and hexagon lattice, respectively, in both the [100] and [110] direction. The full band gaps are determined from the combination of the results. We have investigated the finite element simulation for the solid/fluid phononic crystal successfully. Both work the results of experiment in the reference and in this work are compared with the FEM simulation. It demonstrates that the finite element method is a good tool for the design of phononic crystal in application to new type sound absorption (isolation) material.

CPU heat sinks with high efficiency of heat transfer are greatly demanded for a personal computer with high-speed computational ability. In recent years, the manufacturing technology of CPU heat sinks has got much attention and becomes indispensable for developing the high-performance CPUs.In this study, some different design criteria for the flow guide and die are proposed during an extrusion process with complex cross-sectional shapes, such as CPU heat sinks. The plastic flow pattern of the billet inside the die cavity is analyzed by using a commercial finite element package ¡§DEFORM 3D¡¨.The extrusion load, the stress and strain distribution of die, and the curvature of the product are investigated. Taguchi method is used to find the optimum extrusion condition of the die parameters. In addition, the experiments of extrusion using Al 6061 were carried out. The plastic flow pattern of the billet within the die and the dead metal zones were observed. The experimental data were compared with the analytical values to verify the validity of the proposed analytical models.