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Yoshiharu Mutoh - One of the best experts on this subject based on the ideXlab platform.

  • Time dependent fatigue Crack Growth Behavior of silica particle reinforced epoxy resin composite
    International Journal of Fatigue, 2016
    Co-Authors: Alisa Boonyapookana, Kohsoku Nagata, Anchalee Saengsai, Supachai Surapunt, Yoshiharu Mutoh
    Abstract:

    Abstract The fatigue Crack Growth Behavior in a silica particle reinforced epoxy resin composite was investigated under two levels of constant K max with various stress ratios R and frequencies, where the ranges of R and frequency were from 0.05 to 0.7 and from 0.1 to 10 Hz, respectively. The Crack Growth rate da/dt under a constant K max was almost constant regardless of R and frequency, which clearly confirmed that the Crack Growth Behavior of the present epoxy resin composite was K max -controlled and time-dependent. The Crack path and fracture surface observations revealed that the Crack propagated mostly in the matrix: even for the Crack propagation along the boundary between silica particle and matrix, the Crack propagated in the matrix near the boundary.

  • Effect of Hold Time on Crack Growth Behavior of Pb-Containing and Pb-Free Solders
    Journal of Electronic Materials, 2012
    Co-Authors: Kittichai Fakpan, Yoshiharu Mutoh, Yuichi Otsuka, Kohsoku Nagata
    Abstract:

    Four types of loading waveforms were adopted to investigate the effect of hold time on Crack Growth Behavior of Sn-37Pb and Sn-3.0Ag-0.5Cu solders: a sinusoidal waveform, triangular waveform, and trapezoidal waveform with hold times of 1 s, 5 s, and 10 s, and a triangular waveform with hold time of 10 s at maximum tensile load. The experimental results showed that the Crack Growth Behavior of both solders tested under sinusoidal and triangular waveforms without any hold time was predominantly cycle dependent. On the other hand, the Crack Growth Behavior of both solders tested under trapezoidal waveforms with hold times of 1 s, 5 s, and 10 s and triangular waveforms with hold time of 10 s was predominantly time dependent. Under cycle-dependent conditions the Crack Growth data were a function of J-integral range, while under time-dependent conditions the Crack Growth data were not a function of the creep J-integral range but rather of the C* parameter.

  • creep fatigue Crack Growth Behavior of pb containingand pb free solders at room and elevated temperatures
    Journal of Electronic Materials, 2012
    Co-Authors: Kittichai Fakpan, Yoshiharu Mutoh, Yuichi Otsuka, Shunsuke Inoue, Kohsoku Nagata, Kazuya Kodani
    Abstract:

    Fatigue Crack Growth tests of lead-containing (Sn-37Pb) and lead-free (Sn-3.0Ag-0.5Cu) solders were conducted at frequencies ranging from 0.1 Hz to 10 Hz at stress ratio of 0.1, at room temperature and at 70°C. The J-integral range (ΔJ) and the modified J-integral (C *) were used in assessing the cycle-dependent and time-dependent Crack Growth Behavior for both solders. The experimental results showed that the Crack Growth Behavior of both solders at the lower frequency and higher temperature was predominantly time dependent, whereas the Crack Growth Behavior of both solders at the higher frequency and lower temperature was predominantly cycle dependent, with the transition in fatigue Crack Growth Behavior from cycle dependent to time dependent expressed as f + 6500exp(1/T) = 6520. In both the cycle-dependent and time-dependent regions, the Crack Growth resistance of the lead-free solder was higher than that of lead-containing solder. Fracture surface observations showed that, as the frequency decreased and/or the temperature increased, the fracture path changed from transgranular to intergranular for Sn-37Pb solder, and from transgranular to mixed transgranular–intergranular for Sn-3.0Ag-0.5Cu solder.

  • Creep–Fatigue Crack Growth Behavior of Pb-Containingand Pb-Free Solders at Room and Elevated Temperatures
    Journal of Electronic Materials, 2012
    Co-Authors: Kittichai Fakpan, Yoshiharu Mutoh, Yuichi Otsuka, Shunsuke Inoue, Kohsoku Nagata, Kazuya Kodani
    Abstract:

    Fatigue Crack Growth tests of lead-containing (Sn-37Pb) and lead-free (Sn-3.0Ag-0.5Cu) solders were conducted at frequencies ranging from 0.1 Hz to 10 Hz at stress ratio of 0.1, at room temperature and at 70°C. The J-integral range (ΔJ) and the modified J-integral (C *) were used in assessing the cycle-dependent and time-dependent Crack Growth Behavior for both solders. The experimental results showed that the Crack Growth Behavior of both solders at the lower frequency and higher temperature was predominantly time dependent, whereas the Crack Growth Behavior of both solders at the higher frequency and lower temperature was predominantly cycle dependent, with the transition in fatigue Crack Growth Behavior from cycle dependent to time dependent expressed as f + 6500exp(1/T) = 6520. In both the cycle-dependent and time-dependent regions, the Crack Growth resistance of the lead-free solder was higher than that of lead-containing solder. Fracture surface observations showed that, as the frequency decreased and/or the temperature increased, the fracture path changed from transgranular to intergranular for Sn-37Pb solder, and from transgranular to mixed transgranular–intergranular for Sn-3.0Ag-0.5Cu solder.

  • fatigue Crack Growth Behavior of silica particulate reinforced epoxy resin composite
    Composites Science and Technology, 2011
    Co-Authors: Alisa Boonyapookana, Kohsoku Nagata, Yoshiharu Mutoh
    Abstract:

    Abstract In the present work, fatigue Crack Growth tests of epoxy resin composite reinforced with silica particle under various R -ratios were carried out to investigate the effect of R -ratio on Crack Growth Behavior and to discuss fatigue Crack Growth mechanism. Crack Growth curves arranged by Δ K showed clear R -ratio dependence even under no Crack closure, where the values of Δ K th were 0.82 and 0.33 MPa √m for R  = 0.1 and 0.7 respectively. However, Crack Growth curves arranged by K max merged into almost one curve regardless of R -ratio, which indicated that Crack Growth Behavior of the present composite was time-dependent. The value of K max, th were in the range from 0.78 to 1.12 MPa √m. In situ Crack Growth observation revealed the Crack Growth mechanism: micro-Cracking near the interface between silica particle and resin matrix occurs ahead of a main Crack and then micro-Cracks coalesce with a main Crack to grow. The Crack path was in the epoxy matrix, which was consistent with the time-dependent Crack Growth.

V Balasubramanian - One of the best experts on this subject based on the ideXlab platform.

  • Fatigue Crack Growth Behavior of Gas Metal Arc Welded AISI 409 Grade Ferritic Stainless Steel Joints
    Journal of Materials Engineering and Performance, 2009
    Co-Authors: A.k. Lakshminarayanan, K. Shanmugam, V Balasubramanian
    Abstract:

    The effect of filler metals such as austenitic stainless steel, ferritic stainless steel, and duplex stainless steel on fatigue Crack Growth Behavior of the gas metal arc welded ferritic stainless steel joints was investigated. Rolled plates of 4 mm thickness were used as the base material for preparing single ‘V’ butt welded joints. Center Cracked tensile specimens were prepared to evaluate fatigue Crack Growth Behavior. Servo hydraulic controlled fatigue testing machine with a capacity of 100 kN was used to evaluate the fatigue Crack Growth Behavior of the welded joints. From this investigation, it was found that the joints fabricated by duplex stainless steel filler metal showed superior fatigue Crack Growth resistance compared to the joints fabricated by austenitic and ferritic stainless steel filler metals. Higher yield strength and relatively higher toughness may be the reasons for superior fatigue performance of the joints fabricated by duplex stainless steel filler metal.

  • Effect of notch location on fatigue Crack Growth Behavior of strength-mismatched high-strength low-alloy steel weldments
    Journal of Materials Engineering and Performance, 2004
    Co-Authors: S. Ravi, V Balasubramanian, S. Nemat Nasser
    Abstract:

    Welding of high-strength low-alloy (HSLA) steels involves the use of low-strength, equal-strength, and high-strength filler materials (electrodes) compared with the parent material, depending on the application of the welded structures and the availability of filler material. In the present investigation, the fatigue Crack Growth Behavior of weld metal (WM) and the heat-affected zone (HAZ) of undermatched (UM), equally matched (EM), and overmatched (OM) joints has been studied. The base material used in this investigation is HSLA-80 steel of weldable grade. Shielded metal arc welding (SMAW) has been used to fabricate the butt joints. A center-Cracked tension (CCT) specimen has been used to evaluate the fatigue Crack Growth Behavior of welded joints, utilizing a servo-hydraulic-controlled fatigue-testing machine at constant amplitude loading ( R =0). The effect of notch location on the fatigue Crack Growth Behavior of strength mismatched HSLA steel weldments also has been analyzed.

Zhipeng Xie - One of the best experts on this subject based on the ideXlab platform.

  • Slow Crack Growth Behavior of silicon nitride ceramics in cryogenic environment
    Ceramics International, 2016
    Co-Authors: Jingya Gui, Sai Wei, Zhipeng Xie
    Abstract:

    Abstract The slow Crack Growth Behavior of Si 3 N 4 ceramics in ambient and cryogenic environment had been investigated by dynamic fatigue testing. The fracture strength was principally dependent on stress rate at 293 K while the fracture strength was comparatively independent of stress rate at 77 K. The morphologies of the fracture surface and the Crack tip region were examined to correlate with the slow Crack Growth Behavior. The experimental results revealed that the Si 3 N 4 ceramics exhibits a very high resistance to slow Crack Growth (SCG) in cryogenic environment. The reasons for such high resistance are likely related to the local residual stress associated with either the thermal anisotropies arising from the presence of the grain boundary glass phase, or from the Crack tip shielding mechanism.

Bernd Oberwinkler - One of the best experts on this subject based on the ideXlab platform.

  • modeling the fatigue Crack Growth Behavior of ti 6al 4v by considering grain size and stress ratio
    Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2011
    Co-Authors: Bernd Oberwinkler
    Abstract:

    Abstract Ti-6Al-4V is a commonly used titanium base alloy in aerospace applications. The increasing demand for damage-tolerant designs of such components necessitates a detailed knowledge of its Crack Growth Behavior. The aim of this research was the characterization and phenomenological modeling of long Crack Growth Behavior with respect to microstructure and stress ratio. Therefore, the long Crack propagation was characterized for eight different heat treatment conditions and four stress ratios. For comparison, physically short Crack Growth tests were also performed. The long Crack Growth threshold was found to be dominated by roughness-induced Crack closure, and the fracture surface roughness is controlled by the primary α-grain size. The reason for this correlation is a near-threshold Crack propagation mode, which is dominated by the transcrystalline fracture of α-grains. This correlation was used to model the Crack Growth threshold with respect to microstructure. A linear relation was determined between the stress ratio and the threshold value, which was also found in this approach. Further presented models cover the Crack Growth Behavior in the near-threshold (Stage I) and mid-Growth rate regions (Stage II).

T. Goswami - One of the best experts on this subject based on the ideXlab platform.

  • Fatigue Crack Growth Behavior of Ti–6Al–4V alloy forging
    Materials & Design, 2003
    Co-Authors: T. Goswami
    Abstract:

    Results of two test programs (TP-1 and TP-2) are presented here to investigate: (1) the transition from Regime I to Regime II fatigue-Crack Growth Behavior in a room-temperature high-humidity environment (TP-1); and (2) elevated-temperature fatigue-Crack Growth Behavior of Ti–6Al–4V alloy (TP-2). Constant-amplitude tests were conducted for both at several stress ratios (R=0.05, 0.4 and 0.7) to study the transition of structure-sensitive fatigue Crack Growth in TP-1, and several temperatures were studied at R=0.1 in TP-2. Middle-tension (MT) specimens were used for the former case, whereas compact-tension specimens were used for the latter. Conventionally forged Ti–6Al–4V alloy processed to a solution-treated and over-aged condition was used for both programs. Temperatures for the TP-2 were: room temperature, 175, 230, 290 and 345 °C. An increase in stress ratio and temperature lowered the transitional stress intensity factor range where Regime I shifts to Regime II (steady-state region). A higher stress ratio accelerated the fatigue Crack Growth rates. However, higher temperature up to 345 °C influenced the Crack Growth rates only marginally. An empirical correlation equation was developed and validated to predict the transitional stress intensity factor for a number of materials. Distinct transition and Crack Growth Behaviors were recorded for each stress ratio and temperature for TP-1 and TP-2, respectively.