The double Wronskian solutions whose entries satisfy matrix equation for a (2+1)-dimensional breaking soliton equation ((2+ 1)DBSE) associated with the ZS-AKNS hierarchy are derived through the Wronskian techn...The double Wronskian solutions whose entries satisfy matrix equation for a (2+1)-dimensional breaking soliton equation ((2+ 1)DBSE) associated with the ZS-AKNS hierarchy are derived through the Wronskian technique. Rational and periodic solutions for (2+1)DBSE are obtained by taking special eases in general double Wronskian solutions.展开更多
Dense arrays of Fe-Cr alloy clusters with different Cr ratios were fabricated by gas-phase cluster beam deposition. The complex multiphase structure and various coupling effects in the cluster arrays were studied. A l...Dense arrays of Fe-Cr alloy clusters with different Cr ratios were fabricated by gas-phase cluster beam deposition. The complex multiphase structure and various coupling effects in the cluster arrays were studied. A lattice mismatched tetragonal-like morphology of the Fe-Cr alloy cluster was observed at large Cr ratio. An exchange bias effect was observed and was shown to be dependent on the proportion of the Cr components in the alloy. With the increase of the Cr composition, the exchange bias field became smaller and stronger dipolar interactions between the clusters developed. Residual coercivity and magnetization, which were more remarkable in the tetragonal-like clusters, were observed above the ferromagnetic-superparamagnetic transition temperature. The experimental results of the coercive field and the bias field at different temperatures demonstrated that the tetragonal-like clusters had better thermal stability and greater anisotropy.展开更多
The method for design and analysis of a buoyancy tank riser tensioner system (BTRTS) was put forward in this paper, taking the free standing hybrid riser's top buoyancy tank as an example. The design procedure was ...The method for design and analysis of a buoyancy tank riser tensioner system (BTRTS) was put forward in this paper, taking the free standing hybrid riser's top buoyancy tank as an example. The design procedure was discussed and was also illustrated in a flowchart, after a short description of the global arrangement, structure configuration, and the function of different types of buoyancy tanks (BT). The objective of this paper is to describe a way of developing a BT with minimal hydro force, maximal net lift, and no redundancy of compartments. The method of determining the main dimensions of the BT, namely the length and the outer diameter, was outlined. A series of investigations was conducted for a West Africa FSHR BT design, and the effect of the ratio of the length to the outer diameter (L/D) on the hydrodynamics and the weight of the BT was discussed. The methodology of designing the internal structure of the BT was presented. The effects of the number of compartments and the dimension of the inner stem on the BT weight and strength were compared. The relationship between inner structure and the number one index of the BT as well as the riser's top tension factor (TTF) were illustrated for normal operating conditions and conditions with one or more compartments (or inner stem) damaged. A design instance was given in this paper, when L/D is 4-6, the BT weight and the drag force are compromised. When the BT is divided into 10 compartments, the riser TTF will reach the maximum value, and the ratio of the stem OD to shell OD is about 0.3. A global strength analysis method of the BT and the main load case matrix was also included in the paper, together with the local strength analysis of the buoyancy tank's pad-eye assembly.展开更多
The present study aims to develop a robust structural damage identification method that can be used for the evaluation of bridge structures. An approach for the structural damage identification based on the measuremen...The present study aims to develop a robust structural damage identification method that can be used for the evaluation of bridge structures. An approach for the structural damage identification based on the measurement of natural frequencies is presented. The structural damage model is assumed to be associated with a reduction of a contribution to the element stiffness matrix equivalent to a scalar reduction of the material modulus. A computational procedure for the direct iteration technique based on the non-linear perturbation theory is proposed to identify structural damage. The presented damage identification technique is applied to the footbridge over the Slunjcica River near Slunj to demonstrate the effectiveness of the proposed approach. Using a limited number of measured natural frequencies, reduction in the stiffness of up to 100% at multiple sites is detected. The results indicate that the proposed approach can be successful in not only predicting the location of damage but also in determining the extent of structural damage.展开更多
Based on relating equation group, a simplified method was presented in terms of the matrix displacement method, which can be conveniently used to study the re-distribution of the internal forces and displacement of tr...Based on relating equation group, a simplified method was presented in terms of the matrix displacement method, which can be conveniently used to study the re-distribution of the internal forces and displacement of truss structures due to the removal of members. Such removal is treated as though adding a load case to the original truss, and the re-distribution can be calculated without modifying the original global stiffness matrix. The computational efficiency of the presented method is faster by square times than that of the matrix displacement method. The results from the two methods are identical.展开更多
The nature and origin of a fundamental quantum QSPR (QQSPR) equation are discussed. In principle, as any molecular structure can be associated to quantum mechanical density functions (DF), a molecular set can be r...The nature and origin of a fundamental quantum QSPR (QQSPR) equation are discussed. In principle, as any molecular structure can be associated to quantum mechanical density functions (DF), a molecular set can be reconstructed as a quantum multimolecular polyhedron (QMP), whose vertices are formed by each molecular DF. According to QQSPR theory, complicated kinds of molecular properties, like biological activity or toxicity, of molecular sets can be calculated via the quantum expectation value of an approximate Hermitian operator, which can be evaluated with the geometrical information contained in the attached QMP via quantum similarity matrices. Practical ways of solving the QQSPR problem from the point of view of QMP geometrical structure are provided. Such a development results into a powerful algorithm, which can be implemented within molecular design as an alternative to the current classical QSPR procedures.展开更多
A novel numerical procedure, which realizes the stochastic analysis with dimensional reduction integration (DRI), C-type Gram-Charlier (CGC) series, and finite element (FE) model, is proposed to assess the proba...A novel numerical procedure, which realizes the stochastic analysis with dimensional reduction integration (DRI), C-type Gram-Charlier (CGC) series, and finite element (FE) model, is proposed to assess the probability distribution of structural per- formance. From the relationship between the weighting function of orthogonal polynomial and probability density function (PDF) of random variable, the numerical integration formulas are derived for moment computation. Then, distribution of structural uncertainty response can be approximated by the CGC series with the calculated moments. Three engineering appli- cations for the distribution of, the maximum displacement of a ten-bar planer truss, natural frequency of an auto frame, and Von-Mises stress of a bending pipe, are employed to illustrate the computational efficiency and accuracy of the proposed methodology. As compared with plain Monte Carlo simulation (MCS), the method can obtain the accurate distribution of structural performance. Especially at the tail region of cumulative distribution function (CDF), results have shown the satisfy- ing estimators for small probabilities, say, Pc [104, 10-3]. That implies the method could be trusted for structural failure prob- ability prediction. As the computational efficiency is concerned, the procedure could save more than two orders of computational resources as compared with the direct numerical integration (NI) and MCS. Furthermore, realization of the procedure does not require computing the performance gradient or Hessian matrix with respect to random variables, or reshaping the finite element matrix as other stochastic finite element (SFE) codes. Therefore, it should be an efficient and reliable routine for uncertainty structural analysis.展开更多
We extend two known dynamical systems obtained by Blaszak, et al. via choosing Casimir functions and utilizing Novikov-Lax equation so that a series of novel dynamical systems including generalized Burgers dynamical s...We extend two known dynamical systems obtained by Blaszak, et al. via choosing Casimir functions and utilizing Novikov-Lax equation so that a series of novel dynamical systems including generalized Burgers dynamical system, heat equation, and so on, are followed to be generated. Then we expand some differential operators presented in the paper to deduce two types of expanding dynamical models. By taking the generalized Burgers dynamical system as an example, we deform its expanding model to get a half-expanding system, whose recurrence operator is derived from Lax representation, and its Hamiltonian structure is also obtained by adopting a new way. Finally, we expand the generalized Burgers dynamical system to the (29-1)-dimensional case whose Hamiltonian structure is derived by Poisson tensor and gradient of the Casimir function. Besides, a kind of (29-1)-dimensional expanding dynamical model of the (29-1)-dimensionaJ dynamical system is generated as well.展开更多
Inspired by the gradient structure of the nature,two gradient lattice structures,i.e.,unidirectional gradient lattice(UGL)and bidirectional gradient lattice(BGL),are proposed based on the body-centered cubic(BCC)latti...Inspired by the gradient structure of the nature,two gradient lattice structures,i.e.,unidirectional gradient lattice(UGL)and bidirectional gradient lattice(BGL),are proposed based on the body-centered cubic(BCC)lattice to obtain specially designed mechanical behaviors,such as load-bearing and energy absorption capacities.First,a theoretical model is proposed to predict the initial stiffness of the gradient lattice structure under compressive loading,and validated against quasi-static compression tests and finite element models(FEMs).The deformation and failure mechanisms of the two structures are further studied based on experiments and simulations.The UGL structure exhibits a layer-by-layer failure mode,which avoids structure-wise shear failure in uniform structures.The BGL structure presents a symmetry deformation pattern,and the failure initiates at the weakest part.Finally,the energy absorption behaviors are also discussed.This study demonstrates the potential application of gradient lattice structures in load-transfer-path modification and energy absorption by topology design.展开更多
Locating arrays are of interest in generating software test suites to cover all t-way component interactions and locate interaction faults in component-based systems.Recently,Tang,Colbourn and Yin made an investigatio...Locating arrays are of interest in generating software test suites to cover all t-way component interactions and locate interaction faults in component-based systems.Recently,Tang,Colbourn and Yin made an investigation into optimal locating arrays in the case where a single fault is to be located.They pointed out that when two or more faults were considered,matters would become rather complicated.To handle those cases generally seems challenging,but is well worth further research.In this paper,we establish a lower bound on the size of locating arrays with at most two faults,and then prove that optimal locating arrays meeting this bound can be equivalently characterized in terms of orthogonal arrays with prescribed properties.Using this characterization,we develop a number of constructions of optimal locating arrays.Two infinite series of optimal locating arrays are then obtained.展开更多
基金Supported by the National Natural Science Foundation of China under Grant No. 10671121
文摘The double Wronskian solutions whose entries satisfy matrix equation for a (2+1)-dimensional breaking soliton equation ((2+ 1)DBSE) associated with the ZS-AKNS hierarchy are derived through the Wronskian technique. Rational and periodic solutions for (2+1)DBSE are obtained by taking special eases in general double Wronskian solutions.
基金supported by the National Natural Science Foundation of China(No.11627806 and No.61301015)the Priority Academic Programme Development of Jiangsu Higher Education Institutions
文摘Dense arrays of Fe-Cr alloy clusters with different Cr ratios were fabricated by gas-phase cluster beam deposition. The complex multiphase structure and various coupling effects in the cluster arrays were studied. A lattice mismatched tetragonal-like morphology of the Fe-Cr alloy cluster was observed at large Cr ratio. An exchange bias effect was observed and was shown to be dependent on the proportion of the Cr components in the alloy. With the increase of the Cr composition, the exchange bias field became smaller and stronger dipolar interactions between the clusters developed. Residual coercivity and magnetization, which were more remarkable in the tetragonal-like clusters, were observed above the ferromagnetic-superparamagnetic transition temperature. The experimental results of the coercive field and the bias field at different temperatures demonstrated that the tetragonal-like clusters had better thermal stability and greater anisotropy.
基金Foundation item: Supported by the National Natural Science Foundation of China (Grant No.51009033).
文摘The method for design and analysis of a buoyancy tank riser tensioner system (BTRTS) was put forward in this paper, taking the free standing hybrid riser's top buoyancy tank as an example. The design procedure was discussed and was also illustrated in a flowchart, after a short description of the global arrangement, structure configuration, and the function of different types of buoyancy tanks (BT). The objective of this paper is to describe a way of developing a BT with minimal hydro force, maximal net lift, and no redundancy of compartments. The method of determining the main dimensions of the BT, namely the length and the outer diameter, was outlined. A series of investigations was conducted for a West Africa FSHR BT design, and the effect of the ratio of the length to the outer diameter (L/D) on the hydrodynamics and the weight of the BT was discussed. The methodology of designing the internal structure of the BT was presented. The effects of the number of compartments and the dimension of the inner stem on the BT weight and strength were compared. The relationship between inner structure and the number one index of the BT as well as the riser's top tension factor (TTF) were illustrated for normal operating conditions and conditions with one or more compartments (or inner stem) damaged. A design instance was given in this paper, when L/D is 4-6, the BT weight and the drag force are compromised. When the BT is divided into 10 compartments, the riser TTF will reach the maximum value, and the ratio of the stem OD to shell OD is about 0.3. A global strength analysis method of the BT and the main load case matrix was also included in the paper, together with the local strength analysis of the buoyancy tank's pad-eye assembly.
文摘The present study aims to develop a robust structural damage identification method that can be used for the evaluation of bridge structures. An approach for the structural damage identification based on the measurement of natural frequencies is presented. The structural damage model is assumed to be associated with a reduction of a contribution to the element stiffness matrix equivalent to a scalar reduction of the material modulus. A computational procedure for the direct iteration technique based on the non-linear perturbation theory is proposed to identify structural damage. The presented damage identification technique is applied to the footbridge over the Slunjcica River near Slunj to demonstrate the effectiveness of the proposed approach. Using a limited number of measured natural frequencies, reduction in the stiffness of up to 100% at multiple sites is detected. The results indicate that the proposed approach can be successful in not only predicting the location of damage but also in determining the extent of structural damage.
基金Fund of Science and Technology Develop-ment of Shanghai ( No. 0 2 ZF14 0 5 6)
文摘Based on relating equation group, a simplified method was presented in terms of the matrix displacement method, which can be conveniently used to study the re-distribution of the internal forces and displacement of truss structures due to the removal of members. Such removal is treated as though adding a load case to the original truss, and the re-distribution can be calculated without modifying the original global stiffness matrix. The computational efficiency of the presented method is faster by square times than that of the matrix displacement method. The results from the two methods are identical.
文摘The nature and origin of a fundamental quantum QSPR (QQSPR) equation are discussed. In principle, as any molecular structure can be associated to quantum mechanical density functions (DF), a molecular set can be reconstructed as a quantum multimolecular polyhedron (QMP), whose vertices are formed by each molecular DF. According to QQSPR theory, complicated kinds of molecular properties, like biological activity or toxicity, of molecular sets can be calculated via the quantum expectation value of an approximate Hermitian operator, which can be evaluated with the geometrical information contained in the attached QMP via quantum similarity matrices. Practical ways of solving the QQSPR problem from the point of view of QMP geometrical structure are provided. Such a development results into a powerful algorithm, which can be implemented within molecular design as an alternative to the current classical QSPR procedures.
基金supported by the Natural Sciences and Engineering Research Council of Canada (NSERC) and the University Network of Excellence in Nuclear Engineering (UNENE) through an Industrial Research Chair program,"Risk-Based Life Cycle Management of Engineering Systems",at the University of Waterloo
文摘A novel numerical procedure, which realizes the stochastic analysis with dimensional reduction integration (DRI), C-type Gram-Charlier (CGC) series, and finite element (FE) model, is proposed to assess the probability distribution of structural per- formance. From the relationship between the weighting function of orthogonal polynomial and probability density function (PDF) of random variable, the numerical integration formulas are derived for moment computation. Then, distribution of structural uncertainty response can be approximated by the CGC series with the calculated moments. Three engineering appli- cations for the distribution of, the maximum displacement of a ten-bar planer truss, natural frequency of an auto frame, and Von-Mises stress of a bending pipe, are employed to illustrate the computational efficiency and accuracy of the proposed methodology. As compared with plain Monte Carlo simulation (MCS), the method can obtain the accurate distribution of structural performance. Especially at the tail region of cumulative distribution function (CDF), results have shown the satisfy- ing estimators for small probabilities, say, Pc [104, 10-3]. That implies the method could be trusted for structural failure prob- ability prediction. As the computational efficiency is concerned, the procedure could save more than two orders of computational resources as compared with the direct numerical integration (NI) and MCS. Furthermore, realization of the procedure does not require computing the performance gradient or Hessian matrix with respect to random variables, or reshaping the finite element matrix as other stochastic finite element (SFE) codes. Therefore, it should be an efficient and reliable routine for uncertainty structural analysis.
基金Supported by the Fundamental Research Funds for the Central University under Grant No.2017XKZD11
文摘We extend two known dynamical systems obtained by Blaszak, et al. via choosing Casimir functions and utilizing Novikov-Lax equation so that a series of novel dynamical systems including generalized Burgers dynamical system, heat equation, and so on, are followed to be generated. Then we expand some differential operators presented in the paper to deduce two types of expanding dynamical models. By taking the generalized Burgers dynamical system as an example, we deform its expanding model to get a half-expanding system, whose recurrence operator is derived from Lax representation, and its Hamiltonian structure is also obtained by adopting a new way. Finally, we expand the generalized Burgers dynamical system to the (29-1)-dimensional case whose Hamiltonian structure is derived by Poisson tensor and gradient of the Casimir function. Besides, a kind of (29-1)-dimensional expanding dynamical model of the (29-1)-dimensionaJ dynamical system is generated as well.
基金the National Natural Science Foundation of China(Grant Nos.11972049 and 12002050)National Key Laboratory Foundation of Science and Technology on Materials under Shock and Im-pact(Grant No.6142902200401)Opening Fund of State Key Laboratory of Nonlinear Mechanics.
文摘Inspired by the gradient structure of the nature,two gradient lattice structures,i.e.,unidirectional gradient lattice(UGL)and bidirectional gradient lattice(BGL),are proposed based on the body-centered cubic(BCC)lattice to obtain specially designed mechanical behaviors,such as load-bearing and energy absorption capacities.First,a theoretical model is proposed to predict the initial stiffness of the gradient lattice structure under compressive loading,and validated against quasi-static compression tests and finite element models(FEMs).The deformation and failure mechanisms of the two structures are further studied based on experiments and simulations.The UGL structure exhibits a layer-by-layer failure mode,which avoids structure-wise shear failure in uniform structures.The BGL structure presents a symmetry deformation pattern,and the failure initiates at the weakest part.Finally,the energy absorption behaviors are also discussed.This study demonstrates the potential application of gradient lattice structures in load-transfer-path modification and energy absorption by topology design.
基金supported by National Natural Science Foundation of China (Grant Nos.10831002,10801104)the Graduate Student Research and Innovation Program of Jiangsu Province (GrantNo.CXZZ11-0084)
文摘Locating arrays are of interest in generating software test suites to cover all t-way component interactions and locate interaction faults in component-based systems.Recently,Tang,Colbourn and Yin made an investigation into optimal locating arrays in the case where a single fault is to be located.They pointed out that when two or more faults were considered,matters would become rather complicated.To handle those cases generally seems challenging,but is well worth further research.In this paper,we establish a lower bound on the size of locating arrays with at most two faults,and then prove that optimal locating arrays meeting this bound can be equivalently characterized in terms of orthogonal arrays with prescribed properties.Using this characterization,we develop a number of constructions of optimal locating arrays.Two infinite series of optimal locating arrays are then obtained.