Based on the compaction characteristic test and the nonlinear compaction deformation characteristics of backfill material, this paper applies the theory of nonlinear elastic foundation of thin plate to establish a mec...Based on the compaction characteristic test and the nonlinear compaction deformation characteristics of backfill material, this paper applies the theory of nonlinear elastic foundation of thin plate to establish a mechanical model of backfill body and roof in solid dense backfill coal mining. This study critically analyses the deflection equation of the roof by the energy method, derives the conditions of roof breakage and combined with concrete engineering practice analyses, determines roof movement regularity and stability in solid dense backfill mining. Analysis of the engineering practice of the 13,120 backfill panel of Pingmei 12# mine shows the theoretical maximum of roof convergence in backfill mining to be415 mm which is in significant agreement with the measured value. During the advancing process of solid backfill mining at the panel, the maximum tensile stress on the roof is less than its tensile strength which does not satisfy the conditions for roof breakage. Drilling results on the roof and ground pressure monitoring show that the integrity of roof is strong, which is consistent with the theoretical calculations described in this study. The results presented in the study provide a basis for further investigation into strata movement theory in solid dense backfill mining.展开更多
Nonlinear behaviors of a free-floating body in waves were experimentally investigated in the present study. The experiments were carried out for 6 different wave heights and 6 different wave periods to cover a relativ...Nonlinear behaviors of a free-floating body in waves were experimentally investigated in the present study. The experiments were carried out for 6 different wave heights and 6 different wave periods to cover a relatively wide range of wave nonlinearities. A charge-coupled device （CCD） camera was used to capture the real-time motion of the floating body. The measurement data show that the sway, heave and roll motions of the floating body are all harmonic oscillations while the equilibrium position of the sway motion drifts in the wave direction. The drift speed is proportional to wave steepness when the size of the floating body is comparable to the wavelength, while it is proportional to the square of wave steepness when the floating body is relatively small. In addition, the drift motion leads to a slightly longer oscillation period of the floating body than the wave period of nonlinear wave and the discrepancy increases with the increment of wave steepness.展开更多
In the paper, it has been described the relative nonsymmetry effects of the super (generalized) nonlinear velocity, time of a particle and its kinetic formulae far the followed body when it moves with high velocity. T...In the paper, it has been described the relative nonsymmetry effects of the super (generalized) nonlinear velocity, time of a particle and its kinetic formulae far the followed body when it moves with high velocity. The nonsymmetry effects can explain the problem appearing in the extention of the life time for the secondary cosmic ray, mu mesons; they also can explain the controversial problem who is more young in the famous twin paradox. Finally, the followed body kinetic formulae for the particle have been founded.展开更多
Nonlinear phenomena are commonly shown in the vocalization of animals and exerts different adaptive functions.Although some studies have pointed out that nonlinear phenomena can enhance the individual identification o...Nonlinear phenomena are commonly shown in the vocalization of animals and exerts different adaptive functions.Although some studies have pointed out that nonlinear phenomena can enhance the individual identification of male Odorrana tormota,whether the nonlinear phenomena play a specific role in the sexual selection of O.tormota remain unclear.Here we presented evidence that there was a significant negative correlation(Pearson:n=30,r=0.65,P<0.001)between the nonlinear phenomena content and snout-vent length in the male O.tormota,and two-choice amplexus experiments showed that female O.tormota preferred male with smaller body size containing higher nonlinear phenomena content in its calls.Phonotaxis experiments also revealed that females preferred calls with higher nonlinear phenomena content.Additionally,compared to the calls with lower nonlinear phenomena content and higher fundamental frequency,there was shorter response time in phonotactic behaviour of female induced by the calls with higher nonlinear phenomena content and lower fundamental frequency.We argue that the nonlinear phenomena content in the calls of male O.tormota can convey its body size information and may provide important clues for female frogs in darkened surroundings to identify males’body size during mate choice,meanwhile,higher nonlinear phenomena content in males’calls may increase the attractiveness of males to females.The results of this study provide confirmation that,for O.tormota,nonlinear phenomena have specific function in mate choice.展开更多
In this paper a nonlinear diffraction theory due to Stoke's 2nd-order wave for computing the wave force on the large body is presented. The radiation condition as r-∞ for 2nd-order scattered potential has been st...In this paper a nonlinear diffraction theory due to Stoke's 2nd-order wave for computing the wave force on the large body is presented. The radiation condition as r-∞ for 2nd-order scattered potential has been studied in connection with asymptotic solutions. A numerical procedure has been developed for the purpose of calculating the nonlinear wave force on the large body with arbitrary shape.展开更多
The configuration boundedness of the three-body model dynamics is studied for Sun-Earth formation flying missions.The three-body formation flying model is built up with considering the lunar gravitational acceleration...The configuration boundedness of the three-body model dynamics is studied for Sun-Earth formation flying missions.The three-body formation flying model is built up with considering the lunar gravitational acceleration and solar radiation pressure.Because traditional linearized dynamics based method has relatively lower accuracy,a modified nonlinear formation configuration analysis method is proposed in this paper.Comparative studies are carried out from three aspects,i.e.,natural formation configuration with arbitrary departure time,initialization time and formation configuration boundedness,and specific initialization time for bounded formation configuration.Simulations demonstrate the differences between the two schemes, and indicate that the nonlinear dynamic method reduces the error caused by the model linearization and disturbance approximation,and thus provides higher accuracy for boundedness analysis,which is of value to initial parameters selection for natural three-body formation flying.展开更多
New developments have been made on the applications of the differential quadrature(DQ)method to analysis of structural problems recently.The method is used to obtain solutions of large deflections, membrane and bendin...New developments have been made on the applications of the differential quadrature(DQ)method to analysis of structural problems recently.The method is used to obtain solutions of large deflections, membrane and bending stresses of circular plates with movable and immovable edges under uniform pressures or a central point load.The shortcomings existing in the earlier analysis by the DQ method have been overcome by a new approach in applying the boundary conditions. The accuracy and the efficiency of the newly developed method for solving nonlinear problems are demonstrated.展开更多
In this study, we numerically investigated the nonlinear focused wave group action on a truncated surface-piercing structure, and developed a two-dimensional fully nonlinear numerical tank using the higher-order bound...In this study, we numerically investigated the nonlinear focused wave group action on a truncated surface-piercing structure, and developed a two-dimensional fully nonlinear numerical tank using the higher-order boundary element method. We determined the amplitude of the wave components of the focused wave group based on the JONSWAP wave spectrum. We discuss the effects of the presence of a surface-piercing structure on the characteristics of the focused wave group and find that the location of the structure does not evidently change the focal location or focal time of the focused wave group. The largest amplitudes of the run-up and horizontal force on the structure occur when the front surface of the structure is at the focal location. The critical draught and breadth of the structure occur when the wave run-up reaches its maximum along the structure.展开更多
The nonlinear radiated waves generated by a structure in forced motion, are simulated numerically based on the potential theory. A fully nonlinear numerical model is developed by using a higher-order boundary element ...The nonlinear radiated waves generated by a structure in forced motion, are simulated numerically based on the potential theory. A fully nonlinear numerical model is developed by using a higher-order boundary element method （HOBEM）. In this model, the instantaneous body position and the transient free surface are updated at each time step. A Lagrangian technique is employed as the time marching scheme on the free surface. The mesh regridding and interpolation methods are adopted to deal with the possible numerical instability. Several auxiliary functions are proposed to calculate the wave loads indirectly, instead of directly predicting the temporal derivative of the velocity potential. Numerical experiments are carried out to simulate the heave motions of a submerged sphere in infinite water depth, the heave and pitch motions of a truncated flared cylinder in finite depth. The results are verified against the published numerical results to ensure the effectiveness of the proposed model. Moreover, a series of higher harmonic waves and force components are obtained by the Fourier transformation to investigate the nonlinear effect of oscillation frequency. The difference among fully nonlinear, body-nonlinear and linear results is analyzed. It is found that the nonlinearity due to free surface and body surface has significant influences on the numerical results of the radiated waves and forces.展开更多
基金supported by the Project Funded by the National Basic Research Program of China (No. 2013CB227905)the Fundamental Research Funds for the Central Universities of China University of Mining and Technology of China (No. 2014YC02)
文摘Based on the compaction characteristic test and the nonlinear compaction deformation characteristics of backfill material, this paper applies the theory of nonlinear elastic foundation of thin plate to establish a mechanical model of backfill body and roof in solid dense backfill coal mining. This study critically analyses the deflection equation of the roof by the energy method, derives the conditions of roof breakage and combined with concrete engineering practice analyses, determines roof movement regularity and stability in solid dense backfill mining. Analysis of the engineering practice of the 13,120 backfill panel of Pingmei 12# mine shows the theoretical maximum of roof convergence in backfill mining to be415 mm which is in significant agreement with the measured value. During the advancing process of solid backfill mining at the panel, the maximum tensile stress on the roof is less than its tensile strength which does not satisfy the conditions for roof breakage. Drilling results on the roof and ground pressure monitoring show that the integrity of roof is strong, which is consistent with the theoretical calculations described in this study. The results presented in the study provide a basis for further investigation into strata movement theory in solid dense backfill mining.
基金financially supported by the National Natural Science Foundation of China(Grant No.11272079)the National Basic Research Program of China(973 Program,Grant No.2011CB013702)
文摘Nonlinear behaviors of a free-floating body in waves were experimentally investigated in the present study. The experiments were carried out for 6 different wave heights and 6 different wave periods to cover a relatively wide range of wave nonlinearities. A charge-coupled device （CCD） camera was used to capture the real-time motion of the floating body. The measurement data show that the sway, heave and roll motions of the floating body are all harmonic oscillations while the equilibrium position of the sway motion drifts in the wave direction. The drift speed is proportional to wave steepness when the size of the floating body is comparable to the wavelength, while it is proportional to the square of wave steepness when the floating body is relatively small. In addition, the drift motion leads to a slightly longer oscillation period of the floating body than the wave period of nonlinear wave and the discrepancy increases with the increment of wave steepness.
文摘In the paper, it has been described the relative nonsymmetry effects of the super (generalized) nonlinear velocity, time of a particle and its kinetic formulae far the followed body when it moves with high velocity. The nonsymmetry effects can explain the problem appearing in the extention of the life time for the secondary cosmic ray, mu mesons; they also can explain the controversial problem who is more young in the famous twin paradox. Finally, the followed body kinetic formulae for the particle have been founded.
基金a grant from the Chinese Natural Science Foundation to Fang ZHANG(NSFC grants 3187223031640073)Anhui Provincial Key Laboratory of the Conservation and Exploitation of Biological Resources(No.591601)。
文摘Nonlinear phenomena are commonly shown in the vocalization of animals and exerts different adaptive functions.Although some studies have pointed out that nonlinear phenomena can enhance the individual identification of male Odorrana tormota,whether the nonlinear phenomena play a specific role in the sexual selection of O.tormota remain unclear.Here we presented evidence that there was a significant negative correlation(Pearson:n=30,r=0.65,P<0.001)between the nonlinear phenomena content and snout-vent length in the male O.tormota,and two-choice amplexus experiments showed that female O.tormota preferred male with smaller body size containing higher nonlinear phenomena content in its calls.Phonotaxis experiments also revealed that females preferred calls with higher nonlinear phenomena content.Additionally,compared to the calls with lower nonlinear phenomena content and higher fundamental frequency,there was shorter response time in phonotactic behaviour of female induced by the calls with higher nonlinear phenomena content and lower fundamental frequency.We argue that the nonlinear phenomena content in the calls of male O.tormota can convey its body size information and may provide important clues for female frogs in darkened surroundings to identify males’body size during mate choice,meanwhile,higher nonlinear phenomena content in males’calls may increase the attractiveness of males to females.The results of this study provide confirmation that,for O.tormota,nonlinear phenomena have specific function in mate choice.
文摘In this paper a nonlinear diffraction theory due to Stoke's 2nd-order wave for computing the wave force on the large body is presented. The radiation condition as r-∞ for 2nd-order scattered potential has been studied in connection with asymptotic solutions. A numerical procedure has been developed for the purpose of calculating the nonlinear wave force on the large body with arbitrary shape.
文摘The configuration boundedness of the three-body model dynamics is studied for Sun-Earth formation flying missions.The three-body formation flying model is built up with considering the lunar gravitational acceleration and solar radiation pressure.Because traditional linearized dynamics based method has relatively lower accuracy,a modified nonlinear formation configuration analysis method is proposed in this paper.Comparative studies are carried out from three aspects,i.e.,natural formation configuration with arbitrary departure time,initialization time and formation configuration boundedness,and specific initialization time for bounded formation configuration.Simulations demonstrate the differences between the two schemes, and indicate that the nonlinear dynamic method reduces the error caused by the model linearization and disturbance approximation,and thus provides higher accuracy for boundedness analysis,which is of value to initial parameters selection for natural three-body formation flying.
文摘New developments have been made on the applications of the differential quadrature(DQ)method to analysis of structural problems recently.The method is used to obtain solutions of large deflections, membrane and bending stresses of circular plates with movable and immovable edges under uniform pressures or a central point load.The shortcomings existing in the earlier analysis by the DQ method have been overcome by a new approach in applying the boundary conditions. The accuracy and the efficiency of the newly developed method for solving nonlinear problems are demonstrated.
基金the National Key R&D Program of China (Grant No.2016YFE0200100)the National Natural Science Foundation of China (Nos.51709038,and 51739010)the Fundamental Research Funds for the Central Universities (No.DUT16RC(3)113).
文摘In this study, we numerically investigated the nonlinear focused wave group action on a truncated surface-piercing structure, and developed a two-dimensional fully nonlinear numerical tank using the higher-order boundary element method. We determined the amplitude of the wave components of the focused wave group based on the JONSWAP wave spectrum. We discuss the effects of the presence of a surface-piercing structure on the characteristics of the focused wave group and find that the location of the structure does not evidently change the focal location or focal time of the focused wave group. The largest amplitudes of the run-up and horizontal force on the structure occur when the front surface of the structure is at the focal location. The critical draught and breadth of the structure occur when the wave run-up reaches its maximum along the structure.
基金supported by the National Natural Science Foundation of China(51222902,51221961,and 51379032)the Program for New Century Excellent Talents in University(NCET-130076)+2 种基金The Fundamental Research Fund for the Central University(HEUCF140103)The Open Fund of State Key Laboratory of Coastal and Offshore Engineering(LP1407)the Lloyd’s Register Foundation (LRF) through the Joint Centre Involving University College London,Shanghai Jiaotong University and Harbin Engineering University
文摘The nonlinear radiated waves generated by a structure in forced motion, are simulated numerically based on the potential theory. A fully nonlinear numerical model is developed by using a higher-order boundary element method （HOBEM）. In this model, the instantaneous body position and the transient free surface are updated at each time step. A Lagrangian technique is employed as the time marching scheme on the free surface. The mesh regridding and interpolation methods are adopted to deal with the possible numerical instability. Several auxiliary functions are proposed to calculate the wave loads indirectly, instead of directly predicting the temporal derivative of the velocity potential. Numerical experiments are carried out to simulate the heave motions of a submerged sphere in infinite water depth, the heave and pitch motions of a truncated flared cylinder in finite depth. The results are verified against the published numerical results to ensure the effectiveness of the proposed model. Moreover, a series of higher harmonic waves and force components are obtained by the Fourier transformation to investigate the nonlinear effect of oscillation frequency. The difference among fully nonlinear, body-nonlinear and linear results is analyzed. It is found that the nonlinearity due to free surface and body surface has significant influences on the numerical results of the radiated waves and forces.
