钢结构梁柱梁翼内侧加劲板补强接头耐震试验及有限元素分析

本研究主要探讨钢结构梁柱补强接头之耐震行为,补强接头的主要方式是采取避免破坏既存建筑物楼板且不会减低楼层净高度要求下,在钢梁翼板内侧与箱形柱间焊加劲板增加梁端近柱面之弯矩强度。为证明此补强接头之耐震行为,共进行六组大尺寸之梁柱接头试验,其中一组为传统未补强之梁柱接头,另外五组为梁翼内侧加劲板补强接头,未补强之梁柱接头及一组补强接头之梁柱焊接工作于1996年前工地现场完成后,于2006年由既存34层大楼切除后运至实验室进行试验,另四组梁柱补强接头之焊接工作均于2006年在实验室内完成。补强接头试体加劲板与梁翼及柱板接合均采用全渗透焊接,梁上下翼板之背垫板均未移除,亦未与柱面进行填角焊接。二组补强接头试体在实验时的韧性行为极佳,试体在历经第一次反复载重测试至超越美国规范AISC(2005)规定之4%弧度层间侧位移角的要求下,并未发生梁柱接头焊道断裂及强度递减的情形。因此将此二组试体分别进行第二次AISC(2005)反复载重测试,在历经第二次反复载重测试至4%弧度的层间侧位移角时,发生较明显之梁挫屈及强度递减,但梁柱界面焊道未断裂。而另外三组补强接头因梁翼板内侧加劲板所提供的劲度及强度不足,与未补强之梁柱接头试体同样在未能达到AISC(2005)所订定之4%弧度层间侧位移角前而发生破坏。本研究并利用非线性有限元素分析程序ABAQUS(2003)仿真梁柱接头试体,以进一步了解梁翼板内侧加劲板传递梁弯矩的贡献,和可能发生接头破坏的区域。根据实验及有限元素分析结果提出设计方法及范例供工程师补强既有钢结构梁柱接头参考。

电热熔渣焊接瑕疵于钢骨箱型柱板破裂的有限元素分析

为探讨焊接瑕疵对于钢骨箱型柱板破裂行为的影响,本文采有限元素分析,根据裂缝尖端开口位移、应力三轴度与破裂指数等行为指标,来评估柱板破裂的可能性。有限元素模型参数分析结果显示,侧垫板间隙与钢梁相对于电热熔渣焊道的偏心等参数对于箱型柱板破裂的影响较小;然而由于电热熔渣焊道的偏心,即使侧垫板与柱板间隙处的电热熔渣焊熔接线至内横隔板的一个较小的距离,也将产生较大的裂缝尖端开口位移、应力三轴度与破裂指数,因而可能造成柱板的破裂。

含挫屈束制消能斜撑构架效应之接合板耐震设计与试验分析

本研究主要探讨挫屈束制消能斜撑构架中梁柱效应及斜撑轴力效应对接合板耐震行为影响,利用一层楼挫屈束制消能斜撑构架试验及非线性有限元素分析,研究接合板在斜撑构架下的受力行为。本研究考虑接合板在同时承受构架效应(梁及柱剪力效应)及斜撑轴力下的影响,提出等效支撑概念计算接合板在受构架开合(梁及柱剪力)下的力量,如此将接合板的受力分为由构架及斜撑分别提供,再由有限元素分析观察的梁与接合板及柱与接合板界面应力分布,计算接合板端部应力值,以设计接合板及加劲板尺寸。藉由试验及有限元素分析所量测的梁、柱及斜撑力量,配合本研究提出的理论计算接合板在受梁柱开合效应下及斜撑力量下的受力模式,比对试验与分析下接合板端部的应力极值,验证此理论准确性,并建议设计准则,以确保接合板在达到设计层间侧位移角时无破坏产生。

隧道开挖支撑收敛约束法之外显分析

收敛约束法理论为隧道支撑设计之简化分析方法。使用隧道收敛计测资料,借以建立隧道掘进效应函数,并依据地盘与支撑系统之组成律模式,推导在静水应力状态下圆形隧道开挖支撑互制行为之解析解。采用约束损失之递增方法,利用简易试算表工具,提出模拟隧道开挖支撑非线性行为之外显分析。经由外显分析与有限元素分析之比较结果显示,相关收敛约束曲线均呈现一致的趋势。外显分析法提供了模拟隧道开挖支撑互制行为之简易且直接的计算分析方法,收敛约束法理论为隧道支撑设计之简化分析方法。使用隧道收敛计测资料,借以建立隧道掘进效应函数,并依据地盘与支撑系统之组成律模式,推导在静水应力状态下圆形隧道开挖支撑互制行为之解析解。采用约束损失之递增方法,利用简易试算表工具,提出模拟隧道开挖支撑非线性行为之外显分析。经由外显分析与有限元素分析之比较结果显示,相关收敛约束曲线均呈现一致的趋势。外显分析法提供了模拟隧道开挖支撑互制行为之简易且直接的计算分析方法。

削切钢盖板梁柱接头设计与耐震行为

本研究的目的为提出新式的梁柱接头以避免在工地现场进行梁柱接头全渗透焊接,同时亦控制塑性变形发生在一简单、可修复的装置(削切盖板)而非钢梁。削切盖板(RFP)以焊接或栓接方式固定于钢管混凝土(CFT)柱,以螺栓或填角焊与梁翼板接合,四组全尺寸削切盖板梁柱接头试体试验结果显示:(1)削切盖板梁柱接头在反复载重作用下均可超越0.04弧度的位移角,而使梁的塑性弯矩强度得以发挥;(2)塑性变形发生在削切盖板而非钢梁上,进而避免钢梁的挫屈;(3)利用有限元素分析程序ABAQUS可预测试体接头的反复载重行为,并证明削切盖板梁柱接头的弹性挠曲劲度与盖板梁柱接头相似,满足刚性接头的劲度要求;(4)削切盖板的非弹性挫屈强度可藉由本研究提出的非线性回归分析模型预测。

扇形焊接开孔于钢骨梁柱接头耐震行为之影响

扇形焊接开孔为进行梁翼板全渗透开槽焊接时所需之工作孔。然而,实尺寸梁柱接头试验证实,传统梁腹板锁螺栓及梁翼板全渗透焊接之钢构造梁柱接头,常于扇形开孔处发生突然性之脆性破坏。本研究采用非线性有限元素分析方法,探讨扇形焊接开孔于钢骨梁柱接头耐震行为上之影响,包括扇形开孔几何形状对接头区力学行为之影响。分析结果显示,平顺接至梁翼板之扇形开孔能将最大塑性应变之发生位置移离扇形开孔根部,减少因几何形状不连续所造成之应力集中现象,降低局部区域之韧性需求;无扇形开孔之梁柱接头可避免有扇形开孔之缺陷,大幅的改善梁柱接头之韧性行为。

颈椎前路生物活性玻璃涂层钛板系统的研制与生物力学评价

目的 研制颈椎前路生物活性玻璃钛板系统（ACBPS），并对其进行生物力学评价。方法 在钛板内面及累钉表面等离子喷涂0.3mm厚的生物活性玻璃涂层。采用18具颈椎标本随机分为ACBPS，颈前路钛板系统（ACPS），和Orion三组，在颈前路减压，植骨及钛板内固定后，行载荷－位移，扭矩和扭转刚度，极限力学性能测定并记录结果，进行对比；另对ACBPS，ACPS行拔出试验和疲劳试验，且以三维有限元素分析验证。结果 在前屈，后伸时ACBPS组的纵向位移降低幅度明显高于ACPS组或Orion组（P＜0．05），同时其纵向位移值明显低于ACPS组或Orion组（P＜0．05）；ACBPS组的扭转矩和扭转刚度以及极限力学性能与ACPS组或Orion组比较均无统计学差异（P＞0．05）；但其在最大拔出力及相对位移和能量吸收值上增明显高于ACPS组和Orion组（P＜0．05）；其疲劳强度586.86MPa，疲劳载荷达6．55×10^5次；有限元计算得出ACBPS孔洞直径和孔边距离处安全范围。结论 ACBPS角能较好地重建颈椎稳定性且有效防止螺钉及系统整体松动，并能通过涂层的固合来降低螺孔周围应力集中从而延长其使用寿命，可供体内较长时间安放。

Three-dimensional electric field calculations for wire chamber using element refinement method in ANSYS

Finite element analysis(FEA) method was employed to perform three-dimensional(3D) electric field simulations for gas detectors with multiple wire electrodes.A new element refinement method developed for use in conjunction with the FEA program ANSYS allows successful meshing of the wires without physically inputting the wires in the chamber geometry. First, we demonstrate a model with only one wire, for which we calculate the potential distributions on the central plane and the end-cap region. The results are compared to the calculations obtained using GARFIELD, a two-dimensional program that uses the nearly exact boundary element method. Then we extend the method to same model, but with seven wires.Our results suggest that the new method can be applied easily to the 3D electric field calculations for complicated gas detectors with many wires and complicated geometry such as multiwire proportional chambers and time projection chambers.

5轴加工机U600

FEELERU-6005轴加工心机，针对模具加工、原型件制作、加工厂等市场应用，以较少的占地面积、精省的结构。FEELERU．600在结构设计上，X、Y、Z三轴重迭简化设计，三轴行程分别为460mm、520mm和400mm，进给速度均为30m／min。箱型结构铸件、最佳化跨距设计，以及底座立拄一体式设计，经FEA有限元素分析，确保整机刚性与稳定性。

Axial Compression Behavior and Analytical Method of L-Shaped Column Composed of Concrete-Filled Square Steel Tubes

Based on the characteristics of an L-shaped column composed of concrete-filled square steel tubes, the axial compression experiment and nonlinear finite element analysis were carried out to study the mechanical property of the L-shaped column. The load-displacement curve for the L-shaped column, the deflection and load-strain curves for the mono columns were obtained by the axial compression experiment. The results show that the L-shaped column exhibits a flexural-torsional buckling failure mode. The numerical simulation by the finite element analysis shows that the bearing capacity and failure mode are in accordance with those of the axial compression experiment and the feasi- bility of the finite element analysis is proved. For the calculation of the bearing capacity of the L-shaped column com- posed of concrete-filled square steel tubes, an analytical method is proposed based on the theory of the elastic stability and spatial truss model. The results of the analytical method are in good agreement with those of the axial compression experiment and the finite element analysis.

An equivalent finite element method to kinetics analysis of complex mechanism

The Finite Element Method was combined with the results from considerable analysis, producing a new kinetics analysis method of EFEM for a mechanism in truss, geared system, and assembled system. The equivalent principle and the motive differential equation of the system were derived by using an equivalent element, a virtual inertia matrix, and a systematic force matrix. The element’s mass matrix expression in the two dimensional and three dimensional mechanisms of the equivalent element was determined. The equivalent mass matrixes fashion of the Jacobin matrix, generalized coordinate matrix, and equivalent forces matrix were also determined. It was validated by two examples that the new method was normal, simple and direct, and had a higher efficiency than alternative methods; this is regardless of whether traditional methods are used with differential equations and calculated by using a computer.

Analysis of Thermal Effects in Laser Rod Pumped by Repetitively Pulsed Laser Diode Array

Based on some assumptions, the numerical model of thermal distribution in solid state laser crystal pumped by pulsed laser diode is set up due to the pumped intensity distribution. Taking into account the property of YAG materials that varies with temperature, the transient temperature distribution of the laser crystal is calculated using finite element method on condition that K is a constant and a function of temperature. Then, the influence of the pumping parameters on the thermal effect in laser crystal is also discussed. This study is helpful to optimize the design of the diode side pumped solid state lasers.

3D FEM analysis for layered rock considering anisotropy of shear strength

An empirical expression of cohesion （C） and friction angle （Ф） for layered rock was suggested. This expression was compared with a test result made by the former researchers. The constitutive relationship of a transversely isotropic medium and Mohr-Coulomb criterion in which C and Ф vary with directions were employed, and a relative 3D elasto-plastic FEM code was developed, in which the important thing was to adopt a search-trial method to find the orientation angle （p） of shear failure plane （or weakest shear plane） with respect to the major principal stress as well as the corresponding C and Ф Taking an underground opening as the calculation object, the numerical analyses were carried out by using the FEM code for two cases of transversely isotropic rock and isotropic rock, respectively, and the computation results were compared. The results show that when the rock is a transversely isotropic one, the distributions of displacements, plastic zones and stress contours in the surrounding rock will be non-axisymmetric along the tunnel＇s vertical axis, which is very different from that of isotropic rock. The stability of the tunnel in transversely isotropic rock is relatively low.

Production TTR modeling and dynamic buckling analysis

In a typical tension leg platform (TLP) design,the top tension factor (TTF),measuring the top tension of a top tensioned riser (TTR) relative to its submerged weight in water,is one of the most important design parameters that has to be specified properly. While a very small TTF may lead to excessive vortex induced vibration (VIV),clashing issues and possible compression close to seafloor,an unnecessarily high TTF may translate into excessive riser cost and vessel payload,and even has impacts on the TLP sizing and design in general. In the process of a production TTR design,it is found that its outer casing can be subjected to compression in a worst-case scenario with some extreme metocean and hardware conditions. The present paper shows how finite element analysis (FEA) models using beam elements and two different software packages (Flexcom and ABAQUS) are constructed to simulate the TTR properly,and especially the pipe-in-pipe effects. An ABAQUS model with hybrid elements (beam elements globally + shell elements locally) can be used to investigate how the outer casing behaves under compression. It is shown for the specified TTR design,even with its outer casing being under some local compression in the worst-case scenario,dynamic buckling would not occur;therefore the TTR design is adequate.

Sustainable Design of Turbofan Engine： A Computer-Aided Design and Finite Element Analysis

A compressive design and analysis of a turbofan engine is presented in this paper. The components of jet engine have been analyzed based on mechanical design concept. An attempt has been to select materials based on sustainability and green design considerations. The energy content （e） of the materials has been one of the parameters for material selection. The choice of material has a substantial impact on cost, manuthcturing process, and the life cycle efficiency. All components nose cone, fan blade, inlet shaft, including compressor has been solid modeled using Siemens NX 11.0 CAD software. The finite element analysis of every component was performed and found safe. A tolerance analysis was performed before assembly of the turbofan engine. A numerical analysis was completed on blade and inlet geometries to determine a more efficient turbofan engine. Thermal analysis was executed oi1 the cone and suitable corrections were made. Finally, the cost and the total energy were estimated to show how much energy is needed to manufacture a turbofan jet engine.

NUMERIC ANALYSIS ON INFLUENCED FACTORS OF DISCONTINUOUS SURFACE DEFORMATION DUE TO STEEPLY-INCLINED SEAM MINING

This paper deals with the shape and influenced factors of surface non-continuous deformation due to mining. With finite element method, analysis are made to derive the relations between discontinuous deformation and mining affection, weak plane’s position & thickness, and mechanical property of weak-plane medium. The mutual affection of multiple weak-planes is also discussed. The results of the paper lay a foundation for constructing the calculation method of surface discontinuous deformation.

Temperature and thermodynamic deformation analysis of the rotors on a twin screw multiphase pump with high gas volume fractions

The pressure increasing process within a twin screw multiphase pump, under the condition of high gas volume fractions (GVFs), induces large temperature and pressure changes that cause the rotors to deform. Rotor deformations heavily influence the backflow of the multiphase fluid through clearances within the twin screw multiphase pump and these deformations may even lead to pump failures. An accurate temperature and pressure distribution on the screw rotors need be obtained before the deformation analysis can be carried out. By means of small temperature and pressure sensors embedded into the groove at the root of the rotors, the temperatures of 12 points on the rotors and the pressure distributions of a twin screw multiphase pump under high GVFs conditions were recorded. Temperature test results were adopted to perform a heat transfer analysis for determining the temperature distribution on the screw rotors. Then deformation analyses, including thermal deformation, force deformation, and total deformation, were conducted according to the pressure and temperature distributions. Deformation analysis for different materials was also conducted under the same boundary conditions. A material was suggested for the manufacturing of rotors in a twin screw multiphase pump under the condition of high gas volume fractions.

Finite element analysis for wellbore stability of transversely isotropic rock with hydraulic-mechanical-damage coupling

The finite element analysis （FEA） technology by hydraulic-mechanical-damage （HMD） coupling is proposed in this paper for wellbore stability analysis of transversely isotropic rock, developed basing on the recently established FEA technology for iso- tropic rock. The finite element （FE） solutions of numerical wellbore model, damage tensor calculation and Pariseau strength criterion for transversely isotropic rock are developed for researching the wellbore failure characteristics and computing the collapse and fracture pressure of laminated rock as shale reservoirs. The classic Blot constitutive for rock as porous medium is introduced to establish a set of FE equations coupling with elastic solid deformation and seepage flow. To be in accord with the inclined wellbore situation, the coordinate transformation for global, wellbore, in-situ stress and transversely isotropic for- mation coordinate systems is established for describing the in-situ stress field and the results in laminated rock. To be in accord with the practical situation, a three-dimensional FIE model is developed, in which several other auxiliary technologies are com- prehensively utilized, e.g., the typical Weibull distribution function for heterogeneous material description and adaptive tech- nology for mesh refinement. The damage tensor calculation technology for transversely isotropic rock are realized from the well-developed continuum damage variable of isotropic rock. The rock is subsequently developed into a novel conceptual and practical model considering the stress and permeability with the damage. The proposed method utilizing Parisean strength cri- terion fully reflects the strength parameters parallel or perpendicular to bedding of the transversely isotropic rock. To this end, an effective and reliable numerically three-step FEA strategy is well established. Numerical examples are given to show that the proposed method can establish efficient and applicable FE model and be suitable for analyzing the state of pore pressure and stress surrounding wellbore, furthermore to demonstrate the effectiveness and reliability of the instability analysis of wellbore failure region and the safe mud weight computation for collapse and fracture pressure of transversely isotropic rock.

An energy harvester combining a piezoelectric cantilever and a single degree of freedom elastic system

This paper presents a type of vibration energy harvester combining a piezoelectric cantilever and a single degree of freedom (SDOF) elastic system. The main function of the additional SDOF elastic system is to magnify vibration displacement of the piezoelectric cantilever to improve the power output. A mathematical model of the energy harvester is developed based on Hamilton's principle and Rayleigh-Ritz method. Furthermore, the effects of the structural parameters of the SDOF elastic system on the electromechanical outputs of the energy harvester are analyzed numerically. The accuracy of the output performance in the numerical solution is identified from the finite element method (FEM). A good agreement is found between the numerical results and FEM results. The results show that the power output can be increased and the frequency bandwidth can be improved when the SDOF elastic system has a larger lumped mass and a smaller damping ratio. The numerical results also indicate that a matching load resistance under the short circuit resonance condition can obtain a higher current output, and so is more suitable for application to the piezoelectric energy harvester.

Assembly variation analysis of flexible curved surfaces based on Bézier curves

Assembly variation analysis of parts that have flexible curved surfaces is much more difficult than that of solid bodies, because of structural deformations in the assembly process. Most of the current variation analysis methods either neglect the relationships among feature points on part surfaces or regard the distribution of all feature points as the same. In this study, the problem of flexible curved surface assembly is simplified to the matching of side lines. A methodology based on Bézier curves is proposed to represent the side lines of surfaces. It solves the variation analysis problem of flexible curved surface assembly when considering surface continuity through the relations between control points and data points. The deviations of feature points on side lines are obtained through control point distribution and are then regarded as inputs in commercial finite element analysis software to calculate the final product deformations. Finally, the proposed method is illustrated in two cases of antenna surface assembly.