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Rinze Benedictus - One of the best experts on this subject based on the ideXlab platform.
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mode i fatigue delamination growth with fibre bridging in multidirectional composite laminates
Engineering Fracture Mechanics, 2017Co-Authors: Liaojun Yao, René Alderliesten, Meiying Zhao, Yi Sun, Licheng Guo, Xiuqi Lyu, Liyong Jia, Rinze BenedictusAbstract:Fatigue delamination in multidirectional composite laminates was experimentally investigated in present study. Both the Paris relation and a modified Paris relation (with a new similitude parameter) were employed to interpret fatigue delamination with significant fibre bridging. The results clearly demonstrated that fatigue delamination was independent of fibre bridging, if a reasonable similitude parameter was used in data reduction. As a result, a master Resistance Curve can be fitted to determine fatigue crack growth with different amounts of fibre bridging. The energy principles were subsequently used to provide physical interpretation on fatigue delamination. The results indicated the energy release for the same fatigue crack growth remained constant with fibre bridging. Bridging fibres in most cases just periodically stored and released strain energy under fatigue loading, but had little contribution to real energy release. The master Resistance Curve was finally applied to predict fatigue delamination with fibre bridging. Acceptable agreement between predictions and experiments was achieved, demonstrating the validation of the modified Paris relation in fibre-bridged fatigue delamination study.
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fibre bridging effect on the paris relation for mode i fatigue delamination growth in composites with consideration of interface configuration
Composite Structures, 2017Co-Authors: Liaojun Yao, René Alderliesten, Rinze Benedictus, Yi Sun, Meiying ZhaoAbstract:Fibre bridging can significantly enhance delamination Resistance making the use of a single Paris Resistance Curve to determine fatigue crack growth insufficient. An empirical Paris-type relation has been developed in a previous study to take fibre bridging into account in fatigue delamination growth. This relation was developed by correlating the Paris constants C and n to the amount of fibre bridging. This paper provides a further investigation on the interface configuration effect on fatigue delamination growth, illustrating the significance of fibre bridging. The results demonstrated that more bridging fibres can be generated in a multidirectional interface, making both log(C) and n significantly depend on fibre bridging. Thus, the method proposed in the previous study is further extended to take into account of the interface configuration effect.
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Bridging effect on mode I fatigue delamination behavior in composite laminates
Composites Part A: Applied Science and Manufacturing, 2014Co-Authors: Liaojun Yao, René Alderliesten, Meiying Zhao, Rinze BenedictusAbstract:Abstract This paper discusses the bridging effect of fibres on mode I fatigue delamination growth in unidirectional and multidirectional polymer composite laminates based on a series of double cantilever beam (DCB) tests. From the results, there is sufficient evidence that fibre bridging can decrease the crack growth rate da/dN significantly, and using only one fatigue Resistance Curve to determine the delamination behavior in composite materials with large-scale fibre bridging may be inadequate. The bridging created in fatigue delamination is different from that of quasi-static delamination at the same crack length. So it is incorrect to use the Resistance Curve (R-Curve) from quasi-static delamination tests to normalize fatigue delamination results.
Liaojun Yao - One of the best experts on this subject based on the ideXlab platform.
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mode i fatigue delamination growth with fibre bridging in multidirectional composite laminates
Engineering Fracture Mechanics, 2017Co-Authors: Liaojun Yao, René Alderliesten, Meiying Zhao, Yi Sun, Licheng Guo, Xiuqi Lyu, Liyong Jia, Rinze BenedictusAbstract:Fatigue delamination in multidirectional composite laminates was experimentally investigated in present study. Both the Paris relation and a modified Paris relation (with a new similitude parameter) were employed to interpret fatigue delamination with significant fibre bridging. The results clearly demonstrated that fatigue delamination was independent of fibre bridging, if a reasonable similitude parameter was used in data reduction. As a result, a master Resistance Curve can be fitted to determine fatigue crack growth with different amounts of fibre bridging. The energy principles were subsequently used to provide physical interpretation on fatigue delamination. The results indicated the energy release for the same fatigue crack growth remained constant with fibre bridging. Bridging fibres in most cases just periodically stored and released strain energy under fatigue loading, but had little contribution to real energy release. The master Resistance Curve was finally applied to predict fatigue delamination with fibre bridging. Acceptable agreement between predictions and experiments was achieved, demonstrating the validation of the modified Paris relation in fibre-bridged fatigue delamination study.
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fibre bridging effect on the paris relation for mode i fatigue delamination growth in composites with consideration of interface configuration
Composite Structures, 2017Co-Authors: Liaojun Yao, René Alderliesten, Rinze Benedictus, Yi Sun, Meiying ZhaoAbstract:Fibre bridging can significantly enhance delamination Resistance making the use of a single Paris Resistance Curve to determine fatigue crack growth insufficient. An empirical Paris-type relation has been developed in a previous study to take fibre bridging into account in fatigue delamination growth. This relation was developed by correlating the Paris constants C and n to the amount of fibre bridging. This paper provides a further investigation on the interface configuration effect on fatigue delamination growth, illustrating the significance of fibre bridging. The results demonstrated that more bridging fibres can be generated in a multidirectional interface, making both log(C) and n significantly depend on fibre bridging. Thus, the method proposed in the previous study is further extended to take into account of the interface configuration effect.
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Bridging effect on mode I fatigue delamination behavior in composite laminates
Composites Part A: Applied Science and Manufacturing, 2014Co-Authors: Liaojun Yao, René Alderliesten, Meiying Zhao, Rinze BenedictusAbstract:Abstract This paper discusses the bridging effect of fibres on mode I fatigue delamination growth in unidirectional and multidirectional polymer composite laminates based on a series of double cantilever beam (DCB) tests. From the results, there is sufficient evidence that fibre bridging can decrease the crack growth rate da/dN significantly, and using only one fatigue Resistance Curve to determine the delamination behavior in composite materials with large-scale fibre bridging may be inadequate. The bridging created in fatigue delamination is different from that of quasi-static delamination at the same crack length. So it is incorrect to use the Resistance Curve (R-Curve) from quasi-static delamination tests to normalize fatigue delamination results.
C J Gilbert - One of the best experts on this subject based on the ideXlab platform.
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crack growth Resistance Curve behavior in silicon carbide small versus long cracks
Journal of the American Ceramic Society, 2005Co-Authors: C J Gilbert, J J Cao, L C De JongheAbstract:Crack-growth Resistance-Curve (R-Curve) behavior for small ( 3 mm) through-thickness cracks is examined in two silicon carbide (SiC) ceramics that have sharply contrasting fracture properties. The first, an in-situ toughened material designated ABC-SiC fails by intergranular fracture, whereas the second, a commercial SiC (Hexoloy SA), fails by transgranular cleavage. In the former microstructure, hot pressing with aluminum, boron, and carbon additives yields a network of plate-shaped grains, and the presence of an amorphous grain-boundary film that is {approximately}1 nm thick promotes debonding and crack deflection. The resultant grain bridging generates R-Curve toughening; in contrast, no evidence of crack-tip shielding is observed in Hexoloy SA. R-Curve behavior has been evaluated using two techniques for the different crack-length regimes: a small-crack R-Curve has been deconvoluted from indentation-strength data and a long-crack R-Curve has been directly measured using fatigue-precracked, disk-shaped compact-tension specimens. Although Hexoloy SA fails catastrophically at <3 MPa{center_dot}m{sup 1/2}, ABC-SiC exhibits much-improved flaw tolerance with significant rising R-Curve behavior and a steady-state fracture toughness of {approximately}9 MPa{center_dot}m{sup 1/2} after crack extension of {approximately}600 {micro}m. In ABC-SiC, however, differences in the behavior of long and small cracks exist for crack sizes of less than {approximately}120 {micro}m, withmore » the small-crack measurements demonstrating much-reduced crack-growth Resistance; this effect is not observed in Hexoloy SA. Microstructural sources of this behavior are discussed.« less
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cyclic fatigue and Resistance Curve behavior of an in situ toughened silicon carbide with al b c additions
Acta Materialia, 1996Co-Authors: C J Gilbert, J J Cao, Warren J Moberlychan, L. C. DejongheAbstract:The room-temperature crack-growth properties of an in situ toughened, monolithic silicon carbide are reported. Hot pressing was performed at 1900°C with 3 wt.% Al, 2 wt.% C and 0.6 wt.% B additions. Compared to a commercial SiC (Hexoloy SA), significant improvements in both the fracture toughness and cyclic fatigue-crack propagation Resistance have been achieved through control of the β to α transformation. Using fatigue-precracked, disk-shaped compact-tension specimens, marked rising Resistance-Curve behavior was measured over the first ∼ 600 μm of crack extension, leading to a “plateau” fracture toughness of Kc ∼ 9.1 MPa√m; this represents more than a threefold increase over the toughness of Hexology, where a Kc value of 2.5 MPa√m was measured with no evidence of a Resistance Curve. Cyclic fatigue-crack growth rates in the toughened SiC were found to be faster than those under sustained loads (static fatigue) at the same stress-intensity level. The cyclic fatigue-crack growth Resistance was found to be far superior to that of Hexology. Whereas cracking in the commercial SiC became unstable when the maximum stress intensity Kmax exceeded ∼ 2 MPa√m, thresholds for fatigue-crack growth in the in situ toughened material exceeded a Kmax of 7 MPa√m. Such dramatic improvements in the crack-growth Resistance of SiC are attributed to a microstructure consisting of a network of interlocking, plate-like predominantly α-phase grains, which combine to both bridge and deflect the crack. Under cyclic loads, fatigue-crack growth is promoted by the cycle-dependent decay in such crack-tip shielding due to frictional-wear degradation of the zone of grain bridging ligaments in the crack wake. These results represent the first reported evidence of cyclic fatigue behavior in a monolithic silicon carbide and the first direct measurement of the Resistance Curve properties in this ceramic.
Meiying Zhao - One of the best experts on this subject based on the ideXlab platform.
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mode i fatigue delamination growth with fibre bridging in multidirectional composite laminates
Engineering Fracture Mechanics, 2017Co-Authors: Liaojun Yao, René Alderliesten, Meiying Zhao, Yi Sun, Licheng Guo, Xiuqi Lyu, Liyong Jia, Rinze BenedictusAbstract:Fatigue delamination in multidirectional composite laminates was experimentally investigated in present study. Both the Paris relation and a modified Paris relation (with a new similitude parameter) were employed to interpret fatigue delamination with significant fibre bridging. The results clearly demonstrated that fatigue delamination was independent of fibre bridging, if a reasonable similitude parameter was used in data reduction. As a result, a master Resistance Curve can be fitted to determine fatigue crack growth with different amounts of fibre bridging. The energy principles were subsequently used to provide physical interpretation on fatigue delamination. The results indicated the energy release for the same fatigue crack growth remained constant with fibre bridging. Bridging fibres in most cases just periodically stored and released strain energy under fatigue loading, but had little contribution to real energy release. The master Resistance Curve was finally applied to predict fatigue delamination with fibre bridging. Acceptable agreement between predictions and experiments was achieved, demonstrating the validation of the modified Paris relation in fibre-bridged fatigue delamination study.
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fibre bridging effect on the paris relation for mode i fatigue delamination growth in composites with consideration of interface configuration
Composite Structures, 2017Co-Authors: Liaojun Yao, René Alderliesten, Rinze Benedictus, Yi Sun, Meiying ZhaoAbstract:Fibre bridging can significantly enhance delamination Resistance making the use of a single Paris Resistance Curve to determine fatigue crack growth insufficient. An empirical Paris-type relation has been developed in a previous study to take fibre bridging into account in fatigue delamination growth. This relation was developed by correlating the Paris constants C and n to the amount of fibre bridging. This paper provides a further investigation on the interface configuration effect on fatigue delamination growth, illustrating the significance of fibre bridging. The results demonstrated that more bridging fibres can be generated in a multidirectional interface, making both log(C) and n significantly depend on fibre bridging. Thus, the method proposed in the previous study is further extended to take into account of the interface configuration effect.
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Bridging effect on mode I fatigue delamination behavior in composite laminates
Composites Part A: Applied Science and Manufacturing, 2014Co-Authors: Liaojun Yao, René Alderliesten, Meiying Zhao, Rinze BenedictusAbstract:Abstract This paper discusses the bridging effect of fibres on mode I fatigue delamination growth in unidirectional and multidirectional polymer composite laminates based on a series of double cantilever beam (DCB) tests. From the results, there is sufficient evidence that fibre bridging can decrease the crack growth rate da/dN significantly, and using only one fatigue Resistance Curve to determine the delamination behavior in composite materials with large-scale fibre bridging may be inadequate. The bridging created in fatigue delamination is different from that of quasi-static delamination at the same crack length. So it is incorrect to use the Resistance Curve (R-Curve) from quasi-static delamination tests to normalize fatigue delamination results.
Silvania Lanfredi - One of the best experts on this subject based on the ideXlab platform.
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negative temperature coefficient thermistor based on bi3zn2sb3o14 ceramic an oxide semiconductor at high temperature
Applied Physics Letters, 2003Co-Authors: Marcos Augusto Lima Nobre, Silvania LanfrediAbstract:Bi1.5ZnSb1.5O7 dielectric ceramic with pyrochlore structure was investigated by impedance spectroscopy from 400 to 750 °C. Pyrochlore was synthesized by the polymeric precursor method, a chemical synthesis route derived from Pechini’s method. The grain or bulk Resistance exhibits a sensor temperature characteristic, being a thermistor with a negative temperature coefficient (NTC). Only a single region was identified on the Resistance Curve investigated. The NTC thermistor characteristic parameter (β) is equal to 7140 °C, in the temperature range investigated. The temperature coefficient of the Resistance (α) was derived, being equal to −4.46×10−2 °C−1 at 400 °C. The conduction mechanism and relaxation are discussed.
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thermistor ceramic with negative temperature coefficient based on zn7sb2o12 an inverse spinel type phase
Applied Physics Letters, 2002Co-Authors: Marcos Augusto Lima Nobre, Silvania LanfrediAbstract:The electric properties of the semiconductor ceramic Zn7Sb2O12 were investigated by impedance spectroscopy. The grain Resistance exhibits a thermistor behavior with negative temperature coefficient. Two regions on the Resistance Curve were identified. Each region shows a different thermistor characteristic parameter (β), which is equal to 3170 and 3845 °C, at measurement temperatures up to 350 °C and above 450 °C, respectively. The temperature coefficient of the Resistance (α) was derived being equal to −2.59×10−2 °C−1 and −1.89×10−2 °C−1, at 350 and 450 °C, respectively. The anomalous behavior of the Resistance is further evidence of phase transition phenomenon.