Residual strength after a creep loading is studied for open hole CFRP laminates. Accelerated tests are performed at the elevated temperatures. The test results show that the residual strengths are not always less than the static strength but sometimes greater than that, depending on the temperature. A digital image correlation (DIC) method is employed for the measurement of in-situ strain distribution around the open hole. DIC result implies splitting damage of loading directional layer has a role playing to enhance the residual strength after creep. Finite element analysis involving cohesive element is implemented in order to verify the splitting-induced residual strength enhancement. The cohesive element has time-dependent strength and toughness. Time-dependent internal damage propagation is thus analyzed. This study suggests the residual strength as a function of creep time once increases via stress-concentration mitigation by splitting damage and then decreases with time due to the degradation of material properties themselves.

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   The effect of strain rate on load-displacement relations by instrumented sharp indentation was investigated in pure copper having strain rate dependence of strength. A micro-indentation test was carried out using sharp indenter (Berkovich type) at a loading rate of 70 mN/s. Finite element method (FEM) was used for the indentation analysis in comparison with experiment. The strain rate dependency of strength for this copper was examined by quasi-static tensile test (2.4×10^-5 and 2.4×10^-3 s^-1) and the impact tensile test by means of one bar method (6.0×10² s^-1). It was shown that the load-displacement curve obtained through the static-FEM analysis were inconsistent with that obtained through the micro-indentation test. The Cowper-Symonds model, which includes the strain rate dependence of strength, was then used in the dynamic-FEM analysis. The load-displacement curves calculated by the Cowper-Symonds model showed good agreement with the experimental results. As a result of the dynamic-FEM analysis, the strain rate at the early stage of testing reached the dynamic strain rate, approximately 3.0×10¹ s^-1, underneath the sharp indenter. Thus, the indentation load-displacement relation was affected by the dynamic strain rate.

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   The Poly (ether-ether-ketone) (PEEK) resin is a kind of super engineering thermoplastics, and has good mechanical properties and high heat resistance. Recently it has been used for the matrix of Carbon Fiber Reinforced Plastics (CFRP) as a substitute material for thermosetting plastics at high temperature because of its fine moldability. For such occasion, it is very important for reliability of these materials to reveal the visco-elastic behavior of polymer materials. In this study, linearity for creep behavior of PEEK and CFRPEEKs were discussed, and the relationship between time and temperature, fiber volume fractions and crystallinity was revealed.
   Bending creep tests were performed on the crystallized PEEK resin and its CFRPs. It was found that master curves of creep compliance were obtained, and the Arrhenius type time -temperature superposition principle was applied for crystallized PEEK resin and its crystallized CFRPs. Effects of crystallinity and fiber volume fractions on creep behavior were considered by making grand master curves and great grand master curve.Great grand master curve and the shift factors for making great grand master curve were approximated with prony-series equation and quadratic expressions. Using these equations, the creep analyses were carried out. The results have a good agreement with the experimental data. And the estimation data was determined with great accuracy.

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   Stress distribution of prismatic bar with 8mm square cross section was measured using the grain growth in an electrodeposited copper foil. The copper foil was adhered to the prismatic bar subjected to cyclic bending-torsion loading. A Schenck-type fatigue testing machine was used, and tests were performed at a frequency of 60 Hz by mounting the bending-torsion fixture in the test machine. The crystallographic orientations of individual grains that undergo grain growth in the foil were analyzed by electron backscatter diffraction (EBSD). Since the grain orientation was controlled by the cyclic stress, {110} pole figure and orientation imaging microscopy (OIM) mapping in an area of 0.18-0.25 mm² were used for measuring the distribution of biaxial stress ratio on a surface of the prismatic bar. Stress distributions obtained by both methods agreed well with the theoretical solution. It was clarified that he method using {110} pole figure can measure the principal stress more accurately than the method using OIM mapping.

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   This paper presents visualization of boiling phenomena and formation of the two-phase flow pattern in a mini tube which has a 0.30mm inner diameter. Test fluid is refrigerant HCFC123. ITO film is formed by vapor deposition over the outer surface of the glass tube. This film is transparent and electrically conductive. Refrigerant HCFC123 is pumped into the glass tube in liquid phase; it then is boiled away by electrical heating. Bubble formation and growth near the onset point of nucleate boiling and the two-phase flow pattern in the low-quality region is recorded via high-speed video camera (10,000 - 50,000 fps). Appearance of bubble formation and growth in a mini-tube depends on heat flux and mass flux. For low heat flux, an isolated bubble grows to occupy the whole tube cross section, and flows in a form resembling a bullet. Liquid film is not observed between this vapor bubble and the inner tube surface, and evaporation is not so dominant. For high heat flux and low mass flux, bubbles grow to coalesce immediately into a long vapor plug; and both nucleate boiling and evaporation from liquid film between the vapor plug and the inner tube surface remain dominant.

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   The foot joint has the great mechanisms. One of significant parts of this mechanism was arch structure. However, the function of it has been remain unclear. To elucidation of this point , it seems to be required the engineering research. In this paper, we compared the foot arch structures of normal and flat foot by the photoelasticity method. We measured the change of the height. We also analyzed the influence of this change on the tendon using 3-dimensional stress freezing method. In first experiment, we compared them using skeletal model, which is known to be a fundamental stress model on the foot joint. Next, in order to compare the results by skeletal model, we made an experiment using reconstructed skeletal muscle and tendon model. According to these experiments, we estimated a stress distribution map of foot. In skeletal foot model, the stress on calcaneus was observed on outside in flat foot compared with normal foot at the ground landing. This difference between normal and flat foot was decrease in the reconstructed skeletal muscle and tendon model. This result suggests the improvement of the tendon function is effective to recover symptoms.

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