[en] The contributed papers which offer a wide range of new ideas and concepts are classified as follows; Fracture Toughness/Ductile Fracture, Fatigue Strength, Fatigue Crack Growth, Low Cycle Fatigue, Creep/Viscoelastic, Numerical Analysis, Deformation Analysis, Probabilistic Approach, Dynamic Response, Stress Corrosion Cracking, Weld, Composites, Ceramics, Experimental Techniques, Experimental Evaluation of SIF, Strength Evaluation and Material Degradation and Life Evaluation

[en] Effects of an accelerated iso-thermal aging (375degC x 66days) and a prestressing on the fracture toughness are examined for a low alloy steel, A533B-1. The elastic-plastic fracture toughness tests were conducted from the transition (-60deg C) up to the upper shelf (300deg C) regions. In the upper shelf region, J_Ic decreases due to above effects. However, if the results are interpreted in terms of of a total J-integral which accounts for J due to pre-loading, they have no effect. So, the main reason for decreasing J_Ic should be attributed to the pre-loading. Also, they have no effect on the tangent of the R-curve. On the other hand, the transition temperature slightly increases. It is judged that the iso-thermal aging promotes embrittlement

[en] Near-threshold fatigue crack growth characteristics and crack closure in an A508-3 steel were investigated at elevated temperatures (80-350degC). The results obtained are summarized as follows: (1) The threshold stress intensity factor range decreases with increasing temperature up to 100degC and it increases afterward. (2) The occurrence of oxidation of crack surfaces has an important role on the near-threshold characteristics. The thin oxidation prevents the formation of fretting oxide debris in crack growth within the temperature range up to 150degC. The thick oxidation induces crack closure at elevated temperatures (288 and 350degC). (3) It can not be possible to detect exactly oxide induced crack closure by the back-face-strain unloading-compliance method

[en] Safety evaluation of the mechanical components with crack-like defects could be treated probabilistically, because the initial size of defects and other parameters are nondeterministic. In case of an actual structure, such as a pressure vessel, the most important defect is the surface flaw. Since the aspect ratio of a crack may change gradually as the crack grows, the life prediction involving surface flaws is not simple. This paper not only presents a method of probabilistic life prediction for the fatigue crack propagation of semi-elliptical surface crack, but also discuss the effects several parameters for the crack propagation life

[en] The objective of this paper is to analyze the crack growth behavior in the variable thickness (thin to thick type) plate having fillet. For this purpose, 3-dimensional finite element analyses were performed to obtain stress intensity factor values and a series of experiments were performed to obtain the crack growth rate. Results show that the K values and the crack growth rates increased near the thickness interface when the fillet radius is relatively large in comparison to the thickness ratio of the plate

[en] An interfacial crack with a kink under anti-plane shear is analyzed. Employing the Wiener-Hopf technique, the solution is obtained. Attention is given to the case of the kink angle ω approaching zero. It is found that the stress intensity factor is discontinuous at ω = 0, while the energy release rate is continuous at ω = 0

[en] Graphites and/or C/C-composites as plasma-facing first wall components for fusion reactor devices are so severely subjected occasionally to plasma disruption, that the thermal shock resistances and fracture toughnesses of these materials must be evaluated selectively to have appropriate performances. This paper deals with the evaluations of the thermal shock resistance and fracture toughness of several kinds of graphites and C/C-composites for candidate first wall component tiles by means of arc discharge heating for disk specimens. The mechanical and fracture mechanics properties for these specimens are also measured. Two graphites and three C/C-composites are irradiated up to about (1.1-1.9) X 10²¹ n/cm² (E > 29fJ) at about 650-1000degC in a fission reactor (Japan Material Testing Reactor, JMTR) and the degradations in the thermal shock resistances and fracture toughnesses and the changes of mechanical and fracture mechanics properties due to the neutron irradiation are quantitatively given

[en] The circumferentially notched medium carbon steel specimens of root radii of 2, 3 and 5 mm were low-cycle fatigued. Meanwhile, the stress-strain response was calculated at the notch root by means of the F.E.M. and the Neuber's law. The crack initiation lives of the notched specimens were dominated well by the equivalent stress, the equivalent plastic strain and the axial plastic strain produced at the notch roots. The axial plastic strain versus crack initiation life curve estimated through the Neuber's law predicts the shorter and the longer lives in the higher and the lower plastic strain regions, respectively. The applicability of the Neuber's law to the estimation of the crack initiation life extends much more in the notched specimen of the smaller root radius. The above three quantities are also the dominant factors for the failure life of the notched specimen, nevertheless the stress and strain gradients develop in the cross section of the notched specimen

[en] The equation for predicting the effects of artificial small defects on the fatigue strength of metals is introduced, and it is applied to the quantitative evaluation of the effects of nonmetallic inclusions on the fatigue strength of high-strength steels. The importance of the concept that nonmetallic inclusions are virtually equivalent to defects, from the viewpoint of fatigue strength and, more practically, are equivalent to small cracks is emphasized. It is shown that nonmetallic inclusions cause relatively low-fatigue strength and large scatter of the fatigue strength of steels with high static strength or high hardness. The statistics of extreme values is used to estimate the expected maximum size of nonmetallic inclusions contained in a definite number of specimens. The lower limit of scatter in the fatigue strength of a high-strength steel is obtained by using the prediction equation for small defects together with the expected maximum size of nonmetallic inclusions

[en] It is well known that the fracture toughness of ferritic low alloy steels decrease after long term exposure at the elevated temperature. The Ductile-Brittle Transition Temperature (DBTT) obtained by the Charpy V-Notch (CVN) impact test is one of the most useful parameters to evaluate the fracture behavior in these steels. However, the preparation of CVN test specimens can not be performed without the partial or total destruction of the components. Small Punch (SP) test has the advantage of using a much smaller specimen size than that of CVN test. In this study, the impact properties of C-0.5Mo, Cr-Mo and Cr-Mo-V steels were examined by use of CVN test and SP test, and a linear correlation between CVNDBTT and SPDBTT was confirmed. However, the estimation of CVNDBTT by SPDBTT using the linear correlation is not completely reliable since a large scatter of the DBTT results in the linear correlation is yielded. In order to improve the accuracy of the estimated CVNDBTT, a multilinear regression analysis was carried out to decrease the scatter caused by the difference of the manufacturing process and the exposed condition. Consequently, the more accurate and reliable regression equation to predict the CVNDBTT was obtained