A practical structural design system for LSI packages has been developed based on object oriented and graphical user interface technologies. An object-oriented technology is applied for creating product model-based analytical model (PBAM) which is independent of analytical method or tool. It is easy to create any CAE model from the PBAM. Graphical user interface is another effective technology for easy operation. Design engineers only have to select a model of interest and revise the dimensions or materials of the package, if necessary. As soon as they finish revising the input data, a CAE model such as finite element meshes are generated and the analysis starts automatically. The life of the solder joints, for example, is automatically evaluated and the results are displayed on a CRT. This system is very effective for designing new, highly reliable LSI packages in a short time.

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At present two theories for the generalized thermoelastic problems are presented. The first theory proposed by Lord and Shulman (L-S theory) admits only one relaxation time: a relaxation time τ that modifies the classical Fourier law. The second one due to Green and Lindsay (G-L theory) involves two relaxation times in a thermoelastic process: a relaxation time τ₀ modifies the classical energy equation and another relaxation time τ₁ changes the Duhamel-Neumann's constitutive relations. This paper is concerned with the thermal and mechanical waves in an infinite plate subjected to impulsive heating on the surface of the plate. The formulation of the problems is based on the G-L theory and the solution are obtained by the method of characteristics. The numerical results are compared with the existing results obtained by the L-S theory. The influence of relaxation times of G-L theory on the thermal and mechanical waves are examined numerically, and the results are shown in figures.

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In this work, the microscopic bifurcation leading to macroscopic localization in elastoplastic, periodic cellular solids is studied. To this end, a general framework of microscopic bifurcation analysis is established on the basis of the up-dated Lagrangian type homogenization theory developed by the present authors. We thus derive the boundary value problem to find microscopic eigenmodes and the orthogonality indicating no influence of the eigenmodes on the macroscopic variation at the onset of microscopic bifurcation. Then, using a substructure-based finite element method, bifurcation analysis and post-bifurcation analysis are performed for cell aggregates of an elastoplastic honeycomb subject to in-plane uniaxial compression. It is shown that in macroscopically unstable states, microscopic bifurcation with multiplicity occurs due to the Bloch wave nature, if the periodic cell number is not small. It is also shown that the Bloch wave consists of longitudinal and transverse components: only the longitudinal one grows to the macroscopic localization of compression type in a cell row perpendicular to the loading axis.

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Seismic damage is significant for civil structures like bridges, highways, gas pipelines, water pipe lines and sewer pipelines. Sewer pipeline breakage is reported in some earthquakes. It is important to know damage state of the sewer pipelines suffered from earthquakes even though the recover of the sewer pipelines are not emergent. To know the damage, a low-cost structural-health-monitoring system is required. In the present study, a new distributed fracture sensor is developed using glass/carbon composites and a tiny embeddable Internet terminal. The Internet terminal has four A/D converter channels and web-server function. This can be embedded in glass composite structures. The new fracture sensor is made from glass/carbon composites. In one of the surface layers, the glass fiber is cut to make a crack starter. The crack start to grow by the large deformation, and the crack breaks electric conductance of the carbon black layer embedded in the glass composites. This causes electric voltage change when the voltage is applied, and the change is monitored through the Internet. Several experiments were performed to confirm the effectiveness of this system here. As a result, this system successfully provided the fracture information through the Internet.

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A general solution for a viscoelastic medium with arbitrary-shaped cavity of free or fixed boundary is given for the cases of uniform in-plane loads at infinity, and shows the closed-form solution. This analysis is based on the complex variable method using the conformal mapping technique and the correspondence principle between elasticity and linear viscoelasticity. Using the solution, the stresses and displacements around arbitrary-shaped cavity of free or fixed boundary are discussed under time variation. Several numerical examples are shown by graphical representation for various arbitrary-shaped cavities.

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In this paper, numerical solutions of singular integral equations are discussed in the analysis of axi-symmetric interface cracks under torsion and tension. The problems of a ring-shaped interface crack are formulated in terms of a system of singular integral equations on the basis of the body force method. In the numerical analysis, the unknown functions of the body force densities are approximated by the products of the fundamental density functions and power series, where the fundamental densities are chosen to express a two-dimensional interface crack exactly. The accuracy of the present analysis is verified by comparing the present results with the results obtained by other researchers for the limiting cases. The calculation shows that the present method gives rapidly converging numerical results for these problems as well as for ordinary crack problems in homogeneous material. The stress intensity factors of a ring-shaped interface crack are shown in tables and charts with varying in material combination and also geometrical conditions.

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In order to study the effect of cleanliness on the step-wise S-N characteristics of high strength steel, cantilever-type rotary bending fatigue tests were conducted in laboratory air at ambient temperature on two kinds of high carbon chromium steels with different cleanliness. In surface-related fracture region, fatigue strength was not dependent on cleanliness, while in subsurface fracture region, the steel with higher cleanliness showed shorter fatigue life and higher transition stress at which the crack initiation site changed from the surface to the subsurface. These were attributed to larger size of inclusions contained in the steel with higher cleanliness. It was confirmed that cleanliness, defined with the number of inclusions, was not a factor controlling subsurface fracture. The S-N characteristics depending on the inclusion size were further discussed on the basis of the relationship between stress intensity factor for inclusion and fatigue life and the size of inclusions from which subsurface fracture occurred.

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In this paper, a growth rate law of a small fatigue crack is proposed for an arbitrary metal. Moreover, another method is proposed for considering a size distribution of spheroidal defects cut by the specimen surface. Both methods are used to predict the high-cycle fatigue life reliability with a large scatter due to the defects. Rotating bending fatigue tests are carried out concretely on a kind of Aluminum Cast Alloy with entectic Si, Fe compounds and porosities. Comparing with experimental data, the validity of the present method predicting for fatigue life reliability from a defect is examined and confirmed.

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The residual strengths of hybrid composites with non-woven carbon tissue (NWCT) are investigated under in-plane compressive static and fatigue loading conditions after contact loading with a steel ball as the indentor. The hybrid composites are made by interleaving the NWCT layer between the CFRP layer interfaces. Four kinds of angle-ply laminates are studied; i.e., CFRP laminates ([45₅/-45₅/45₅] and [45₃/-45₃/45₃/-45₃/45₃]), and hybrid laminates ([45₅//-45₅//45₅] and [45₃//-45₃//45₃//-45₃//45₃]). The symbol "//" means that the NWCT layer is located at an interface between CFRP layers. In the previous study, the delamination areas of the hybrid composites were reduced to about a half of the CFRP's by the indentation loading. Based on this result, in this report, the residual compressive strengths of the hybrid composites are expected to be improved by the interaction between the indentation damage and in-plane compressive loading conditions. Fatigue lives of the hybrid composites under compression-compression fatigue loading were significantly extended in all stress ranges. The compressive static and fatigue failure processes are discussed from observation of the fracture surfaces of damaged parts and failed specimens' appearances when subjected to compression after the damaged.

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Creep behavior of symmetric angle-ply laminates of T 800 H/3631 at high stress and high temperature has been examined. Constant-stress creep tests in tension are performed at 100°C on the plain coupon specimens of three types of angle-ply laminates: [±30]s, [±45]s, [±60]s. For each ply orientation, the creep tests are carried out at three different stress levels. Creep recovery tests are consecutively conducted also for five hours at the same temperature, after completely removing the creep stress for each of the five-hour creep. Creep responses are clearly observed in all kinds of angle-ply laminate. The creep strain rate of the angle-ply laminates tends to rapidly disappear as the creep strain increases. The transient creep is thus dominant for the system, regardless of ply orientation. The creep strain is not completely recovered with time after removing the creep stress. The classical laminated plate theory with a phenomenological viscoplasticity model for plies succeeds in favorably reproducing the creep behavior of the angle-ply CFRP laminates at high stress and high temperature. It is also demonstrated that a consideration of the relative rotation of plies results in better predictions.

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An X-ray stress measuring method for a silicon single crystal is proposed. Various stresses σ_a were applied to a silicon single crystal wafer specimen, and the strains of different diffraction planes were measured by X-rays. The variation of peak positions at various ψ angles caused by various applied stresses σ_a was investigated. The measured peak positions were plotted in the sin²ψ diagram for various applied stresses σ_a. Although the peak positions of different diffraction planes in the sin²ψ diagram deviated from a straight line determined by the least squares method, the straight lines crossed at a point, and the slope M and intercept N of the straight line varied linearly with the applied stress σ_a. This shows that the peak position and the strain for a fixed ψ angle vary proportionally to the applied stress σ_a. For plane stress state, the residual stress of a silicon single crystal specimen can be determined using the slope M and intercept N.

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Rotating bending fatigue tests were carried out for a radical nitrided SNCM 439 steel in order to investigate the influence of compound layers on the fatigue strength and fracture mechanism. By nitriding at 480°C to the steel quenched at 835°C and tempered at 160°C, the fatigue strength increased, though the internal matrix softened and the static strength decreased. In both of the nitrided steel and the quench-tempered steel, fish-eye fracture occurred in long life region, and the fracture initiated from a specimen surface in short life region. By removing the compound layers in the nitrided steel, the fatigue strength decreased dramatically and the fracture origin changed from a subsurface to a specimen surface. That is, compound layers make the fatigue life increase through both of the suppression of the initiation of a surface crack and the change of fracture origin.

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Rotating bending fatigue teats were carried out for an aluminum oxide-dispersion-strengthening copper alloy at room temperature and 350°C, in order to investigate the influence of elevated temperature on the fatigue strength of notched member. Fatigue limit for crack initiation at 350°C decreased similar to the static strength by softening, whereas, fatigue limit for crack propagation was higher at 350°C than at room temperature. These facts were discussed from a view-point of the influence of oxidation at 350°C on the crack initiation and propagation.

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Infrared thermography (TVS) is a device for conducting thermal radiation pattern from an object into a visible image. We paid attention to heat generation by plastic deformation and discussed the possibility of applying this device to detecting local plastic deformation by thermal video system. In measuring surface temperature distribution by this device, the emissivity is a very important factor of measuring the surface temperature distribution and largely depend upon the surface roughness. In this study, the relation between the emissivity and surface roughness was examined and we discussed the thermal image processing technique of the thermal image obtained by TVS.

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High refractory and corrosion resistant pressure sensor with tantalum/SUS 316 welding type diaphragm has been developed for hydrogen iodide cycling test in thermo chemical hydrogen production process and tested its fatigue and corrosion properties. With these results, the following conclusions were derived. (1) New type of high refractory and corrosion resistant alloy was found in Ta/SUS 316 welding region and its elemental composition was identified as 83Ta-11Fe-2Ni-2Cr-2Mo[wt.%]. (2) This pressure sensor achieved a new record of the longest fatigue life over 10⁷ cycles within 0.44%F.S./°C and (3) No degradation of its mechanical and sensitivity properties was found after 20 000 hours hydrogen iodide cycling test.

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