A Thick Plate Problem Under the Action of a Body Force in Generalized Thermoelasticity

The two-dimensional problem for a thick plate is considered within the context of the theory of generalized thermoelasticity with one relaxation time under the action of a body force. The upper surface of the plate is subjected to a known temperature distribution, while its lower one is laid on a thermally insulated rigid foundation. Laplace and exponential Fourier transform techniques are used. The solution in the transformed domain is obtained by a direct approach. The inverse double transform is evaluated numerically. The distributions of the considered physical variables are obtained and represented graphically.     

Plane Waves of a Fiber-Reinforcement Magneto-thermoelastic Comparison of Three Different Theories

In this article, the coupled theory, Lord–Shulman theory, and Green–Lindsay (GL) theory are used to study the influence of a magnetic field on a fiber-reinforced thermoelastic half-space. Normal mode analysis is used to solve a thermal shock problem. Numerical results for the temperature, displacement components, and stress components are given and illustrated graphically. A comparison is made between the coupled and GL theories in the absence and presence of a magnetic field and reinforcement.     

The Effect of Magnetic Field on 2-D Problem for a Mode-I Crack of a Fiber-Reinforced in Generalized Thermoelasticity

In the present paper, the coupled theory, Lord–?hulman theory, and Green–Lindsay theory are introduced to study the influence of a magnetic field on the 2-D problem of a fiber-reinforced thermoelastic. These theories are also applied to study the influence of reinforcement on the total deformation of an infinite space weakened by a finite linear opening Mode-I crack. The material is homogeneous and an isotropic elastic half-space. The crack is subjected to a prescribed temperature and stress distribution. Normal mode analysis is used to solve the problem of a Mode-I crack. Numerical results for the temperature, the displacement, and thermal stress components are given and illustrated graphically in the absence and the presence of the magnetic field. A comparison between the three theories is also made for different depths.     

The Influence of Gravitational Field on Generalized Thermoelasticity with Two-Temperature under Three-Phase-Lag Model

The problem of the generalized thermoelastic medium for three different theories under the effect of a gravitational field is investigated. The Lord- Shulman, Green-Naghdi III, three-phase-lag theories are discussed with twotemperature. The normal mode analysis is used to obtain the analytical expressions of the displacement components, force stress, thermodynamic temperature and conductive temperature. The numerical results are given and presented graphically, when the thermal force is applied. Comparisons are made with the results predicted by three-phase-lag model, Green-Naghdi III and Lord-Shulman theories in the presence and absence of gravity as well as two temperature.     

Generalized Thermoelasticity of Thermal-Shock Problem in a Non-homogeneous Isotropic Hollow Cylinder with Energy Dissipation

A solution of a thermal-shock problem of generalized thermoelasticity of a non-homogeneous isotropic hollow cylinder using a finite-element method is developed. The formulation is applied to the generalized thermoelasticity based on the Green and Naghdi (GN) theory of type II and type III by an appropriate choice of parameters. The problem has been solved numerically using a finite-element method. Numerical results for the distributions of displacement, temperature, radial stress, and hoop stress are represented graphically. The results indicate that the effects of non-homogeneity are very pronounced. The effects of non-homogeneity are presented with the two types of the Green and Naghdi theory.     

关系营销理论探讨--三种理论的区别和联系

关系营销是一种新型的营销理论，它是随着经济技术的发展和竞争的日益激烈而逐步发展起来的。对于关系营销不同角度的研究形成了不同的理论学派。本文介绍了在关系营销研究中具有代表性的三种理论学派，即承诺－信任理论、六市场模型和关系、网络、互动理论，指出这三种理论是从不同的层面研究关系营销的，尽管其研究角度不同，但是理论之间存在着一定的联系。认识到这一点，对于企业营销管理的研究实践活动具有重要的意义。     

一种指尖三维力传感器设计

设计了一种用于仿人灵巧手的指尖三维力传感器,采用十字梁与中心直梁相结合的结构实现对三维力的感知。首先利用ANSYS工具对设计的十字梁弹性体进行静力学分析,通过分析对弹性体的结构尺寸进行了优化,并给出了最佳贴片方案;最后对设计的指尖三维力传感器进行静态标定试验,建立了维间耦合误差模型,利用静态解耦算法对传感器耦合误差进行解耦计算,有效提高了指尖三维力传感器的测量精度。实验结果表明:设计的三维指尖力传感器的测量精度优于2.5%。     

T-Stress of a Bi-Material Strip Under Generalized Edge Loads

An expression for the T-stress in a bi-material strip with a semi-finite interfacial crack is derived for general edge loads using a conservation integral method. The expression is explicit except for two non-dimensional constants, which are determined from a finite element analysis and which are tabulated as a function of the Dundurs’ parameters and the thickness ratio of the strip.     

The Probe Length Effect on the Cantilever of an Atomic Force Microscope in Measuring the Mechanical Properties of Living Neurons

Living sensory neurons were studied by atomic force microscopy in the PeakForce QNM mode under near-physiological conditions. The dependence of the measured apparent Young modulus of cells on the ratio of the probe height to the beam length on a used cantilever was revealed. A qualitative explanation based on the analysis of beam strains in two limit cases, in which the probe slides over a studied object and the probe sticks to the latter, was given to the obtained result. It was proposed to classify native cells by the character of their interaction with the probe (sliding or sticking).     

Transient Disturbance in a Half Space Under Thermoelasticity with Two Relaxation Times Due to Moving Internal Heat Source

In this paper transient waves caused by a line heat source moving with a uniform velocity inside isotropic homogeneous thermoelastic half-space are studied under the GL model of generalized thermoelasticity. The problem is reduced to the solution of three differential equations by introducing the elastic vector potential and the thermoelastic scalar potential. Using Laplace and Fourier transforms solutions are obtained in transforms domain. Applying inverse transforms approximate solutions of the displacement at the boundary valid in the small time range are given. Also the approximate region valid for the solutions is given and two special cases, (i) the source is motionless and (ii) the relaxation times vanish, are studied. Numerical evaluations are presented for the medium of copper.     

Generalized Thermoelastic Medium with Temperature-Dependent Properties for Different Theories under the Effect of Gravity Field

The problem of the generalized thermoelastic medium for three different theories under the effect of a gravity field is investigated. The Lord–Shulman (L–S), Green–Lindsay (G–L), and classical-coupled (CD) theories are discussed. The modulus of the elasticity is given as a linear function of the reference temperature. The exact expressions for the displacement components, temperature, and stress components are obtained by using normal mode analysis. Numerical results for the field quantities are given in the physical domain and illustrated graphically in the absence and presence of gravity. A comparison also is made between the three theories for the results with and without a temperature dependence.     

Reflection of Magneto-Thermoviscoelastic Waves Under Generalized Thermoviscoelasticity

Considering each of the thermal fields, viscoelastic and electromagnetic fields contribute to the total deformation of a body and interact with each other. Reflection of magneto-thermoelastic waves under generalized thermoviscoelastic theories is employed to study the reflection of plane harmonic waves from a semi-infinite elastic solid in a vacuum. The expressions for the reflection coefficients, which are the ratios of the amplitudes of the reflected waves to the amplitudes of the incident waves, are obtained, and the reflection coefficient ratios variation with the angle of incidence under different conditions are shown graphically when acrylic plastic materials are considered.     

机械制冷机微振动固支测力修正

机械制冷机微振动固支测力结果的工程应用存在载荷值有误差和加载位置不明确两方面问题。基于动力学分析提出一种微振动固支测力修正方法,将测得的作用在测力台面几何中心的微振动力转化为作用在制冷机动子处的微振动力,实现了制冷机微振动力与其支撑结构刚度和质量解耦。修正所得的力频谱特性反映了制冷机实际输出的微振动力频谱特性,力的作用位置为制冷机微振动实际产生位置,解决了测力结果工程应用存在的问题,修正结果可应用于制冷机的微振动特性评估和微振动响应分析。     

类金刚石薄膜中杂质Fe对其力学性能的影响

描述了利用射频等离子体溅射法采用不同阴极在衬底Ｓｉ片上形成类金刚石薄膜的杂质含量及杂质对厚度和硬度的影响分析与结果,比较了ＤＬＣ膜的力学性能在有无金属杂质情况下的异同,分析和计算了其硬度与硬度与制备参数间的关系,得出利用石墨作电极能制备出质量较好的ＤＬＣ膜,初步探讨在Ｓｉ衬底上沉积高硬度和强附着度类金刚石薄膜的有关工艺条件,并在理论上对这一结果进行了解释。     

力学因素对钢中氢扩散行为的影响

采用阴极电解渗氢法和气相色谱测氢法研究了塑性变形和负载应力对氢在钢中的溶解和逸出的影响,认为:随塑性变形和负载应力的增加氢的溶解度和溶解时的扩散系数增大,溶解扩散激活能减小;氢逸出时的扩散系数减小逸出扩散激活能增大;电解渗入的氢有一部分不能扩散逸出,这部分残留下来的氢随溶解氢量的提高而增加;溶解扩散系数比逸出扩散系数大一个数量级。     

纳米二氧化钛对质子辐照下MQ增强硅橡胶力学性能的影响

采用空间综合辐照模拟设备研究了纳米二氧化钛对100 keV和150 keV能量质子辐照下MQ增强加成型硅橡胶力学性能的影响。试验结果表明,质子辐照后,未添加纳米粒子的硅橡胶表面颜色明显加深,同时出现不同程度的老化龟裂裂纹,裂纹数量和深度随辐照能量和剂量的增加而增加;硅橡胶的硬度和拉伸强度随辐照剂量的增加先增加而后降低。添加纳米二氧化钛的硅橡胶与未改性硅橡胶相比,经过相同能量、剂量的质子辐照后,表面颜色加深和表面裂纹损伤的程度均减小,硬度和力学性能的损伤程度下降,表现出明显的抗质子辐照性能。     

Thermoelasticity models taking account of a finite heat propagation rate

An analysis is made of the stationary wave process in a one-dimensional thermoelastic medium on the basis of two heat-conduction models. The nature of the change in the phase velocities, the damping coefficients, the coefficient of connectedness, and the phase-shift angle are established.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 35, No. 2, pp. 344–351, August, 1978.     

纳米TiO2对真空紫外辐照下MQ增强硅橡胶力学性能的影响

采用空间综合辐照模拟设备研究了纳米TiO2对真空紫外辐照下MQ(MQ硅树脂是由单官能硅氧单元(R3SiO0.5,简称M单元)和四官能硅氧单元(SiO2,简称Q单元)组成的有机硅树脂),增强硅橡胶力学性能的影响。试验结果表明,真空紫外辐照后,硅橡胶表面颜色加深,同时出现裂纹,裂纹数量随辐照剂量的增加而增加;在试验的辐照剂量范围内,硅橡胶的硬度和拉伸强度随辐照剂量的增加先增加而后降低,断裂伸长率则先降低而后增加。橡胶的模量和玻璃化转变温度也会发生不同变化。添加纳米TiO2的硅橡胶与未改性硅橡胶相比,经过相同剂量的辐照后,表面裂纹损伤程度减小,硬度和力学性能的损伤程度下降,表现出明显的抗真空紫外辐照性能。