bluuebunny/crossref_metadata_2025_split huggingface dataset:
Dynamic Green's Functions for Anisotropic Materials Under Anti-Plane Deformation
Authors: Wu Kuang-Chong 
Published: May 2011

ABSTRACTThe dynamic Green's function due to an impulse in an infinite anisotropic medium under anti-plane deformation is derived by the method of Smirnov [1] for two-dimensional wave equation. The Green's function is inversely proportional to the time t and an effective dynamic shear modulus. It is shown that the tractions on the planes passing through the source point vanish identically. Based on the free-space Green's function, the Green's functions for wedges, semi-infinite media and strips are obtained.
Boundary Weight Functions for Cracks in Three-Dimensional Finite Bodies
Authors: Ma Chien-Ching , Shen I-Kuang 
Published: May 2011

ABSTRACTAn efficient boundary weight function method for the determination of mode I stress intensity factors in a three-dimensional cracked body with arbitrary shape and subjected to arbitrary loading is presented in this study. The functional form of the boundary weight functions are successfully demonstrated by using the least squares fitting procedure. Explicit boundary weight functions are presented for through cracks in rectangular finite bodies. If the stress distribution of a cut out rectangular cracked body from any arbitrary shape of cracked body subjected to arbitrary loading is determined, the mode I stress intensity factors for the cracked body can be obtained from the predetermined boundary weight functions by a simple integration. Comparison of the calculated results with some solutions by other workers from the literature confirms the efficiency and accuracy of the proposed boundary weight function method.
An Overall Approach for Microcrack and Inhomogeneity Toughening in Brittle Solids
Authors: Pan Huang Hsing 
Published: May 2011

ABSTRACTBased on the weight function theory and Hutchinson's technique, the analytic form of the toughness change near a crack-tip is derived. The inhomogeneity toughening is treated as an average quantity calculated from the mean-field approach. The solutions are suitable for the composite materials with moderate concentration as compared with Hutchinson's lowest order formula. The composite has the more toughened property if the matrix owns the higher value of the Poisson ratio. The composite with thin-disc inclusions obtains the highest toughening and that with spheres always provides the least effective one. For the microcrack toughening, the variations of the crack shape do not significantly affect the toughness change if the Budiansky and O'Connell crack density parameter is used. The explicit forms for three types of the void toughening and two types of the microcrack toughening are also shown.
The Re-Evaluation of Structural Reliability based on Identification Results
Authors: Liu Pei-Ling , Chen Yi-Song 
Published: May 2011

AbstractThis paper develops a method to re-evaluate the reliability of a structure after a period of service. System identification is performed on the structure to identify the current properties of the structure. The Bayesian approach is adopted to modify the prior distributions of the properties based on the identification results. Then, reliability analysis is performed on the structure using the updated distributions of the properties. Sensitivity analysis is also performed to attain the maintenance strategy.
Study on Asymmetrical Sheet Rolling by the Finite Element Method
Authors: Hwang Yeong-Maw , Chen Dyi-Cheng , Tzou Gow-Yi 
Published: May 2011

AbstractAdopting the DEFORM software for the finite element analysis, this study simulated steady-state plastic deformation of the sheet at the roll-gap during asymmetrical sheet rolling. Using FEM code DEFORM, the effects of roll speed ratio, roll radius ratio, friction factor ratio upon the curvature of the rolled product and rolling force were systematically discussed. With a view to verifying the validity of the study simulated, a series of experiments on asymmetrical cold sheet rolling using Aluminum sheet as specimen are carried out. The comparisons between numerical and experimental results show good agreement. Therefore, this numerical model using DEFORM software can offer useful knowledge for designing the pass-schedule of asymmetrical sheet rolling.
Dynamic Analysis and Ride Quality Evaluation of Railway Vehicles – Numerical Simulation and Field Test Verification
Authors: Fan Y.-T. , Wu W.-F. 
Published: May 2011

AbstractA rather complete dynamic model with special emphases on nonlinear conicity and creep force and in consideration of random irregularity of rail profile is proposed to simulate the response and investigate the ride quality of railway vehicles. The CP341 vehicle that will soon be used in Taipei Rapid Transit System is considered in particular as the studied role model. Some of the field test data carried out for this type of vehicle are revealed as well and used for the verification of the proposed model. Both simulation and test results show that the resonant frequency of the studied vehicle is in the range of 0.6∼1 Hz, and the one-third octave root-mean-square acceleration curves of the vehicle in all studied cases meet the ride quality criteria set for the mass rapid transit vehicle systems. It is observed that the secondary suspension of the vehicle has the low frequency filtering property and the primary suspension has high frequency characteristics. A poorer ride quality in vertical direction rather than in lateral direction is also confirmed in the study. It is concluded that the proposed model can be used to simulate the dynamic response and evaluate the ride quality of any railway vehicle.
Parametric Study on Bone Screw Designs for Holding Power
Authors: Chao C.-K. , Hsiao C.-C. 
Published: May 2011

AbstractPullout tests of bone screws have been performed on cadaver bones, animal bones or synthetic bones. These materials have been proven to be poor models from experimental observation, giving results with too much variability or difference. The finite element method was used in this study to evaluate the holding power for bone screws subject to the changes of outer diameter, inner diameter, pitch and radiuses of tip and bottom round corner. The displacement control mode was used in a way that 1 mm displacement was applied on the flatness region of bone screw head and the reaction force was then recorded to simulate the ability of pullout force. Numerical results showed that the patterns of tip corner on the bone screw were a deciding factor on the pullout force of bone screw. This study was significant for establishing a good bone-screw FEM model and suggesting important threaded parameters in selecting or manufacturing a bone screw to increase its holding power.
Effects of Couple Stresses on Pure Squeeze EHL Motion of Circular Contacts
Authors: Chu H.-M. , Li W.-L. , Hu S. Y. 
Published: May 2011

AbstractA method for investigating the pure squeeze action in an isothermal elastohydrodynamically lubrication (EHL) problem, i.e., circular contacts lubricated with couple stress fluid, was developed. A constant load condition was used in the calculations. The initial conditions such as pressure profiles, normal squeeze velocities, and film shapes were obtained from the classical hydrodynamic lubrication theory at a specified large central film thickness. The coupled transient modified Reynolds, elasticity deformation, and load equilibrium equations are solved simultaneously. The simulation results reveal that the effect of the couple stress is equivalent to enhancing the lubricant viscosity, thus enlarging the film thickness. The effect of couple stress in thin film lubrication varies with film size. That is, the thinner the lubricating film is, the more obvious the effect of couple stress is. For larger characteristic length, materials parameter, and load, the central pressure, central film thickness, and rigid separation are larger than those of smaller characteristic length under the same load. The time needed to achieve maximum central pressure and the Hertzian pressure increases with increasing characteristic length.
Analysis of Pipe-Soil Interaction for a Miniature Pipejacking
Authors: Shou K. J. , Chang F. W. 
Published: May 2011

AbstractIn this study, physical and numerical models were used to analyze pipe-soil interaction during pipejacking work. After calibrating with the physical modeling results, the finite element software ABAQUS [1] was used to study the pipejacking related behavior, such as surface subsidence, failure mechanism, pipe-soil interaction, etc. The results show that the driving force in the tunnelling face is very important and critical for pipejacking. Surface subsidence is mainly due to the lack of driving force, however, excessive driving force could cause the unfavorable surface heaving problem. It also suggests that the depth of the pipe is critical to determine a proper driving force to stabilize the tunnelling face.
Method of Fundamental Solutions for Plate Vibrations in Multiply Connected Domains
Authors: Tsai C. C. , Young D. L. , Fan C. M. 
Published: May 2011

AbstractThis paper develops the method of fundamental solutions (MFS) to solve eigenfrequencies of plate vibrations of multiply connected domains. The complex-valued MFS combined with the mix potential method are utilized in order to avoid the spurious eigenvalues. The benchmarked problems of annular plates with clamped, simply supported and free boundary conditions are studied analytically as well as numerically. Wherein the results demonstrate that all true eigenvalues are contained and no spurious eigenvalues are included. In the analytical studies, the continuous version of the MFS is utilized to obtain the eigenequation by applying the degenerate kernels and Fourier series. The proposed numerical method is free from singularities, meshes, and numerical integrations and thus can be easily utilized to solve plate vibrations free from spurious eigenvalues in multiply connected domains.
Natural Convection Heat and Mass Transfer From a Horizontal Cylinder of Elliptic Cross Section with Constant Wall Temperature and Concentration in Saturated Porous Media
Authors: Cheng C.-Y. 
Published: May 2011

AbstractThis work studies the natural convection heat and mass transfer near a horizontal cylinder of elliptic cross section with constant wall temperature and concentration in a fluid-saturated porous medium. A coordinate transformation is used to obtain the nonsimilar governing boundary layer equations. The transformed governing equations are then solved by the cubic spline collocation method. Results for the local Nusselt and Sherwood numbers are presented as functions of the Lewis number, the buoyancy ratio, and the aspect ratio when the major axis of the elliptical cylinder is vertical (slender orientation) and horizontal (blunt orientation). The heat and mass transfer rates of the elliptical cylinder with slender orientation are higher than those with blunt orientation.
Stiffness Matrices for Linear and Buckling Analyses of Composite Beams with Partial Shear Connection
Authors: Leu L.-J. , Huang C.-W. 
Published: May 2011

AbstractThis paper is concerned with linear and buckling analyses of composite beams with partial shear connection (partial composite beams) using the finite element method. Two elements derived from different types of shape functions are proposed in this study. The first element, referred to as exact, is based on the exact shape functions obtained by solving the differential equations governing the transverse displacement and the slip of the shear connector layer of a partial composite beam. The second element, referred to as approximate, is based on the conventional linear and cubic shape functions used in conventional axial and beam elements. By making use of these two types of shape functions, the elastic and geometric stiffness matrices can be derived explicitly from the strain energy and the load potential, respectively. Both types of elements can be used to carry out linear static and buckling analyses. As expected, the exact element is more accurate than the approximate element if the same discretization is adopted. However, the approximate element has the advantage of easy implementation since the expressions of its elastic and geometric stiffness matrices are very simple. Also, the solutions obtained from the approximate element converge very fast; with reasonable discretization, say 8 elements per member, very accurate solutions can be obtained.
Analysis of Newmark Explicit Integration Method for Nonlinear Systems
Authors: Chang S.-Y. , Huang Y.-C. , Wang C.-H. 
Published: May 2011

AbstractNumerical properties of the Newmark explicit method in the solution of nonlinear systems are explored. It is found that the upper stability limit is no longer equal to 2 for the Newmark explicit method for nonlinear systems. In fact, it is enlarged for stiffness softening and is reduced for stiffness hardening. Furthermore, its relative period error increases with the increase of the step degree of nonlinearity for a given value of the product of the natural frequency and the time step. It is also verified that the viscous damping determined from an initial stiffness is effective to reduce displacement response in the solution of a nonlinear system as that for solving a linear elastic system. All the theoretical results are confirmed with numerical examples.
A Model of Damage and Creep Interaction in a Quasi-Brittle Composite Material Under Axial Loading
Authors: Taha M. M. Reda , Shrive N. G. 
Published: May 2011

AbstractCreep is the time-dependent, viscoelastic strain observed in materials under constant stress. Creep can increase structural strains/deformations to non-serviceable levels or alter the stress distribution among structural components. While stress redistribution can be helpful in composite materials by relieving the stress on one component, it might have a detrimental effect on another, especially if it leads to overstressing.A step-by-step in time approach for modeling creep in quasi-brittle materials such as concrete and masonry is utilized, and a new continuum damage model based on Weibull's failure rate distribution is introduced. A multiplicative approach to integrate the creep and damage effects within the step-by-step in time analysis is invoked. The significance of the proposed approach is exemplified through analysis of a clay masonry column filled with grout and subjected to concentric axial load. It is shown that the proposed approach can provide insights on the stress evolution in both components of the composite material that might not be inferred using classical methods of analysis.
A Note on the Transient Solution of Stokes' Second Problem with Arbitrary Initial Phase
Authors: Liu C.-M. , Liu I.-C. 
Published: May 2011

AbstractThe flow of a viscous fluid disturbed by an oscillating plate of arbitrary initial phase is studied in present note. The exact solutions of the velocity and the shear stress are solved using a Laplace transform method. The velocity is derived in terms of complementary error functions and the shear stress on the boundary is given in the form of Fresnel integrals. Since the steady-state solutions are well known, our discussions are focused on the transient solutions. The transient state will disappear faster for the wall stress than that for the velocity field. Comparing the results corresponding to different initial phases, the cosine case reaches to the steady state more rapidly than the sine case.
Anisotropic Strength Characteristics of Composite Soil Specimen Under Cubical Triaxial Conditions
Authors: Lin H.-D. , Chen W.-C. 
Published: May 2011

AbstractThis paper provides 41 cubical triaxial test results to examine the influence of the stress path angle and the improvement ratio on the anisotropic strength of the composite soil specimens consisting of remolded soft clay and grout columns. Pictures of failed samples shown in this paper are especially enlightening in demonstrating failure mechanisms. Results from this study can be summarized as follows. The composite soil specimens exhibited different failure patterns depending on the stress path angle, axial compression failure for 0°, 30° and 60°; lateral compression for 120° and 150°; and axial extension for 90° and 180°. Consistently, diagonal shear cracks through the grout column were observed for axial compression failure samples. On the other hand, tension cracks were observed for samples which failed due to lateral compression and axial extension. The composite soil specimens exhibited apparent anisotropic behavior. In general, the anisotropic strength ratio increased with the improvement ratio. The equivalent strength formula commonly used in practice may give erroneous results, especially when the stress paths are those of tension failure. In such a case, the anisotropic strength ratio suggested in this paper can significantly improve its accuracy.
Characterizing the Sound Insulation of a Specially Orthotropic Multi-Layered Medium
Authors: Lin H.-J. , Wang C.-N. , Kuo Y.-M. 
Published: May 2011

AbstractThis work explores the sound transmission loss provided by the orthotropic multi-layers to elucidate the sound insulation of FRP (Fiber Reinforced Plastics). Mat is the major material considered in the numerical works. The transfer matrices of a single layer of the orthotropic laminate and the fluid are determined. Further, the boundary conditions on the various interface planes are arranged into matrix form. Combining the transfer matrixes and the boundary conditions and applying the transfer matrix method (TMM) yields the surface impedance and the sound transmission loss. The sound-propagation characteristics are studied. Additionally, the STC (Sound Transmission Class) of FRP and steel are compared and discussed.
Finite Element Analysis of Structures with Interval Parameters
Authors: Gao W. 
Published: May 2011

AbstractThis paper present a new method called the interval factor method for the finite element analysis of truss structures with interval parameters. Using the interval factor method, the structural parameters and loads can be considered as interval variables, and the structural stiffness matrix can then be divided into the product of two parts corresponding to its deterministic value and the interval factors. The computational expressions for lower and upper bounds, mean value and interval change ratio of structural placement and stress responses are derived from the static governing equations by means of the interval operations. The effect of the uncertainty of the structural parameters and loads on the structural static responses is demonstrated by truss structures.
Application of Normalized Spectral Acceleration-Displacement (NSAD) Format on Performance-Based Seismic Design of Bridge Structures
Authors: Sung Y.-C. , Chang S.-Y. , Lai M.-C. , Lin T.-W. , Tsai I.-C. 
Published: May 2011

AbstractFor a bi-linear SDOF system subjected to a specific wave form of the ground acceleration, the unique yielding pseudo spectral acceleration and spectral displacement (Say, Sdy) together with various inelastic responses (Sai, Sdi) can be obtained via nonlinear time history analyses, respectively, by tuning the different levels of peak ground acceleration as various input ground motions. Meanwhile, the corresponding elastic responses (Sae, Sde) of a linear SDOF system with the identical mass, viscous damping and elastic stiffness as those of the bi-linear one can also be determined through linear time history analyses under the same excitations. The proposed NSAD format shown on the diagram of the elastic force ratio, Ω=Sae/Say I Say, versus the ductility ratio, (μ= (Sdi/Sdy), is a dimensionless plot of the seismic demands suitable to the engineers who are familiar with the conventional force-based design using linear structural analysis. In this paper, more than two hundred ground motions recorded in the Chi-Chi earthquake, Taiwan (1999) were chosen as the seismic inputs for the establishment of the NSAD format. The characteristics and applications of the NSAD format on the performance-based seismic design of the bridge structures were discussed, and realistic procedures for the methodology were proposed.The results obtained shows that the NSAD format can help the engineers evaluate the multiple-level seismic demands not only with a well precision but also with a great convenience.
Design and Development of a Piezoelectric Actuator for the Scanning Probe Microscope Used in Ultrahigh Vacuum
Authors: Huang K.-Y. , Lee C.-J. 
Published: May 2011

AbstractThis paper is to present the design and development of a piezoelectric actuator for SPM in ultrahigh vacuum (10−7∼10−9 Torr). The measuring probe is installed on a precise scanning actuator, which is further driven by a fast approaching actuator. The precise scanning actuator composed of a piezo-tube with segmented electrodes can realize 3-D precise scanning motions at subnanometer level to move the measuring probe over the measured surface. Because of its stable and smooth actuating behavior, the inchworm actuating principle is selected for the fast approaching actuator, which is build up with two controllable clamping devices and an actuating device. Diverse flexure mechanisms are applied in the actuator to attain frictionless guiding and recovery functions. To realize balanced clamping forces on the scanning tube, each clamping device is integrated with a fine regulating mechanism for clamping force. By applying the theoretical model and the finite element analysis, the relations between force and deflection inside the actuator were investigated to validate its function. The developed actuator has sustained the severe baking and pumping process, and their function and performance were verified experimentally in ultrahigh vacuum.
Stability Analysis on Viscous Magnetic Fluid Film Flowing Down Along a Vertical Cylinder
Authors: Cheng P.-J. , Liu K.-C. 
Published: May 2011

AbstractThe paper investigates the hydromagnetic stability theory of a thin electrically conductive fluid film flowing down along the outside surface of a vertical cylinder. The long-wave perturbation method is employed to solve for generalized kinematic equations with free film interface. The normal mode approach is used to compute the stability solution for the film flow. The modeling results display that the degree of instability in the film flow is further intensified by the lateral curvature of cylinder. This is somewhat different from that of the planar flow. It is also observed that by increasing the effect of the magnetic field and increasing the radius of the cylinder the film flow can become relatively more stable as traveling down along the vertical cylinder.
A Material Function of Endochronic Theory and its Application to Test Under Axisymmetrically Cyclic Loading Conditions
Authors: Lin H.-Y. , Yeh W.-C. , Lee W.-J. 
Published: May 2011

AbstractA material function of endochronic theory is proposed for investigating the plastic behaviors of material. Depending on the material parameters properly chosen, the present model can be classified into four categories, and is appropriate for describing various materials behaving cyclic strain hardening inherently with respect to the deformation history. Experimental verification of the theory was demonstrated using the experimental results of Shiao [1] and Lamba and Sidebottom [2]. The theory is in good agreement with experimental results obtained by Shiao [1] through comparing the stress-strain hysteresis loops of SAE 4340 steel under axisymmetrically cyclic loading condition with various amplitudes. In addition, the present model is shown to be capable of describing the behavior of erasure of memory of materials, as experimentally observed by Lamba and Sidebottom [2].