To systematically validate and calibrate the theory and technology of the deep in-situ conditionpreserved coring, the in-situ conditions at different depths should be simulated, and the full-size coring tests should b...To systematically validate and calibrate the theory and technology of the deep in-situ conditionpreserved coring, the in-situ conditions at different depths should be simulated, and the full-size coring tests should be carried out in this simulated environment. Therefore, a deep-rock in-situ conditionpreserved coring calibration platform was designed and developed. The self-tightening sealing structure and the quick-disassembly structure were designed on the basis of an innovative segmented nonuniformdiameter structure, which was a breakthrough from the traditional high-pressure vessel frame and was verified by finite element simulation and actual testing under extreme working conditions, respectively.To simulate the actual deep in-situ environment with a temperature of 150℃ and pressure of 140 MPa for a large Φ450 mm×H1400 mm core, temperature and pressure control systems were designed by coupling, and a pre-embedded high-pressure-resistant temperature sensor was designed. Finally, highprecision assembly automation, complex movement coordination of the coring device with the platform,and rotary dynamic sealing were achieved by utilizing the combination of adaptive cabin body servo control and an adaptive mechanical structure in a limited space, laying a solid foundation for the calibration of in-situ condition-preserved coring.展开更多
The simulation of crack propagation processes in rock engineering has been not only a research hot spot among scholars but also a challenge.Based on this background,a new numerical method named improved kernel of smoo...The simulation of crack propagation processes in rock engineering has been not only a research hot spot among scholars but also a challenge.Based on this background,a new numerical method named improved kernel of smoothed particle hydrodynamics(IKSPH)has been put forward.By improving the kernel function in the traditional smoothed particle hydrodynamics(SPH)method,the brittle fracture characteristics of the base particles are realized.The particle domain searching method(PDSM)has also been put forward to generate the arbitrary complex fissure networks.Three numerical examples are analyzed to validate the efficiency of IKSPH and PDSM,which can correctly reveal the morphology of wing crack and the laws of crack coalescence compared with previous experimental and numerical studies.Finally,a rock slope model with complex joints is numerically simulated and the progressive failure processes are exhibited,which indicates that the IKSPH method can be well applied to rock mechanics engineering.The research results showed that IKSPH method reduces the programming difficulties and avoids the traditional grid distortion,which can provide some references for the application of IKSPH to rock mechanics engineering and the understanding of rock fracture mechanisms.展开更多
1.Introduction The lasting drive for improved energy efficiency in power gen-eration encourages the innovative design of advanced structural materials with superb mechanical properties[1-6].Among these materials,order...1.Introduction The lasting drive for improved energy efficiency in power gen-eration encourages the innovative design of advanced structural materials with superb mechanical properties[1-6].Among these materials,ordered intermetallic alloys[7-9],as a unique class of metallic materials,have drawn increasing concern from both the scientific and industrial communities due to their intriguing high-temperature properties,strong chemical binding,and low atomic mobility[10,11].However,in light of the insufficient number of slip systems and/or intrinsically weak grain boundary(GB),they are usually brittle at ambient temperature,severely hindering their practical use in engineering systems[12].Previous studies reported that the change in alloy stoichiometry has a significant beneficial effect on the ductility of intermetallic alloys.For instance,Liu et al.展开更多
Shape memory alloys can recover the deformed shape due to their superelasticity or shape memory effect. In this study, a novel Cu-Al-Mn-Fe shape memory single crystal is reported. The results show that it has excellen...Shape memory alloys can recover the deformed shape due to their superelasticity or shape memory effect. In this study, a novel Cu-Al-Mn-Fe shape memory single crystal is reported. The results show that it has excellent superelasticity and shape memory effect simultaneously when deformed at room temperature, as well as tunably wide response temperature range with near-zero interval of reverse phase transformation. When deforming one single crystal at room temperature, it not only possesses full superelasticity of 7%, but also tunable shape memory effects up to 8.8 %. The full shape recovery during heating exhibits near-zero response interval and tunably wide response temperature range of 166 K depending on the deformation. The functional characteristics of the alloys result from the controllable reverse phase transformation hinging on the stabilization of stress-induced martensite. This class of Cu-Al-Mn-Fe alloy may be used as both superelastic materials, and shape memory materials with wide working temperature range as high-sensitive detector, driver or sensor.展开更多
基金supported by National Natural Science Foundation of China(Nos.51827901 and 52225403)the Shenzhen National Science Fund for Distinguished Young Scholars(RCJC20210706091948015).
文摘To systematically validate and calibrate the theory and technology of the deep in-situ conditionpreserved coring, the in-situ conditions at different depths should be simulated, and the full-size coring tests should be carried out in this simulated environment. Therefore, a deep-rock in-situ conditionpreserved coring calibration platform was designed and developed. The self-tightening sealing structure and the quick-disassembly structure were designed on the basis of an innovative segmented nonuniformdiameter structure, which was a breakthrough from the traditional high-pressure vessel frame and was verified by finite element simulation and actual testing under extreme working conditions, respectively.To simulate the actual deep in-situ environment with a temperature of 150℃ and pressure of 140 MPa for a large Φ450 mm×H1400 mm core, temperature and pressure control systems were designed by coupling, and a pre-embedded high-pressure-resistant temperature sensor was designed. Finally, highprecision assembly automation, complex movement coordination of the coring device with the platform,and rotary dynamic sealing were achieved by utilizing the combination of adaptive cabin body servo control and an adaptive mechanical structure in a limited space, laying a solid foundation for the calibration of in-situ condition-preserved coring.
基金financial supports of the National Natural Science Fund(Nos.U1765204 and 51409170)。
文摘The simulation of crack propagation processes in rock engineering has been not only a research hot spot among scholars but also a challenge.Based on this background,a new numerical method named improved kernel of smoothed particle hydrodynamics(IKSPH)has been put forward.By improving the kernel function in the traditional smoothed particle hydrodynamics(SPH)method,the brittle fracture characteristics of the base particles are realized.The particle domain searching method(PDSM)has also been put forward to generate the arbitrary complex fissure networks.Three numerical examples are analyzed to validate the efficiency of IKSPH and PDSM,which can correctly reveal the morphology of wing crack and the laws of crack coalescence compared with previous experimental and numerical studies.Finally,a rock slope model with complex joints is numerically simulated and the progressive failure processes are exhibited,which indicates that the IKSPH method can be well applied to rock mechanics engineering.The research results showed that IKSPH method reduces the programming difficulties and avoids the traditional grid distortion,which can provide some references for the application of IKSPH to rock mechanics engineering and the understanding of rock fracture mechanisms.
基金the City University of Hong Kong ac-knowledge the financial support from the National Natural Sci-ence Foundation of China(Grant Nos.52101151 and52222112)the Hong Kong Research Grant Council(RGC)(Grant Nos.CityU 21205621,11214820,11209021,and C1017-21 G)+2 种基金the Guang-dong Basic and Applied Basic Research Foundation(Grant No.2020A1515110647)Y.L.Z.is grateful for financial support from the National Natural Science Foundation of China(No.52101135)the Shenzhen Science and Technology Program(Grant No.RCBS20210609103202012).
文摘1.Introduction The lasting drive for improved energy efficiency in power gen-eration encourages the innovative design of advanced structural materials with superb mechanical properties[1-6].Among these materials,ordered intermetallic alloys[7-9],as a unique class of metallic materials,have drawn increasing concern from both the scientific and industrial communities due to their intriguing high-temperature properties,strong chemical binding,and low atomic mobility[10,11].However,in light of the insufficient number of slip systems and/or intrinsically weak grain boundary(GB),they are usually brittle at ambient temperature,severely hindering their practical use in engineering systems[12].Previous studies reported that the change in alloy stoichiometry has a significant beneficial effect on the ductility of intermetallic alloys.For instance,Liu et al.
基金financially supported by the National Natural Science Foundation of China (No. 51971185)the National Key R&D Program of China (No. 2017YFB0702901)。
文摘Shape memory alloys can recover the deformed shape due to their superelasticity or shape memory effect. In this study, a novel Cu-Al-Mn-Fe shape memory single crystal is reported. The results show that it has excellent superelasticity and shape memory effect simultaneously when deformed at room temperature, as well as tunably wide response temperature range with near-zero interval of reverse phase transformation. When deforming one single crystal at room temperature, it not only possesses full superelasticity of 7%, but also tunable shape memory effects up to 8.8 %. The full shape recovery during heating exhibits near-zero response interval and tunably wide response temperature range of 166 K depending on the deformation. The functional characteristics of the alloys result from the controllable reverse phase transformation hinging on the stabilization of stress-induced martensite. This class of Cu-Al-Mn-Fe alloy may be used as both superelastic materials, and shape memory materials with wide working temperature range as high-sensitive detector, driver or sensor.
