25 February 2005, Volume 26 Issue 1

    

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  Generation and application of the orthogonal curvilinear coordinate grid in Humen estuary

  BAO Yun, ZHOU Shu-hua, HU Ru-gen

  Journal of Jinan University Natural Science & Medicine Edition. 2005, 26(1): 1-4.

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  The orthogonal curvilinear coordinate grid for Humen estuary is generated. Using it, a numerical experiment is implemented. The computation result of fluid field proved that the orthogonal curvilinear coordinate grid for Humen estuary is successful and it can be used in later research.
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  Analysis on critical flow velocities and destabilizing deflection curves of an element model for parallel-plate fuel assembly

  CUI Zhen-dong, GUO Chang-qing

  Journal of Jinan University Natural Science & Medicine Edition. 2005, 26(1): 5-7.

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  The critical flow velocities of an experimental model for the parallel-plate type fuel element assembly are theoretically and numerically analyzed. This structure is treated as multi-parallel beams joined with single-beams. According to the equations of deflection curves of beams, the continuity conditions and equilibrium at the joints, an eigen-equation is obtained for solving the critical flow velocities and destabilizing deflection curves, and it is numerically solved with implicit iteration method.
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  Buckling state of annular plates under non-axisymmetric loading

  GONG Liang-gui, Sheng Dong-fa

  Journal of Jinan University Natural Science & Medicine Edition. 2005, 26(1): 8-11,34.

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  Under the conditions of von Kármán theory,general mathematical theory for perforated thin plates is established.In polar coordinate,fundamental boundary value problems including the control differential equations,border condition and displacement single value condition are obtained.According to variational principle and finite element method,buckled states of annular plates subjected to non-axisymmetric loading are studied. The critical loading is calculated too.
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  Nonlinear dynamic equation of mid-thick viscoelastic plates with damage

  SHENG Dong-fa, GONG Liang-gui

  Journal of Jinan University Natural Science & Medicine Edition. 2005, 26(1): 12-15.

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  A set of geometric nonlinear dynamic equations for mid-thick viscoelastic plates with damage is derived by adopting the Timoshenko geometric deformation theory and analysis method of geometric nonlinear for thick viscoelastic plates. This set of the equations is of nonlinear integral-partial differential equations with five unknown functions. It can be simplified into the set of dynamic equations for mid-thick viscoelastic plates as the damage is neglected.
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  Bending analysis of FRMP pipes of filament-wound under external loads

  LI Yong, WANG Fan, LIU Ren-huai

  Journal of Jinan University Natural Science & Medicine Edition. 2005, 26(1): 16-19.

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  In engineering permission range, the basic theory of Laminated Composite Cylindrical Shells is simplified by using Donnel-Mushtali approximate theory. Bending analysis of FRMP pipes of filament-wound under external pipe loads is solved by means of the method of double Fourier series. Finally, an engineering example of FRMP pipes under radial and axes loads is given.
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  Inversion of the damage in concrete medium by transient wave field

  LUO Song-nan, ZHANG Wei

  Journal of Jinan University Natural Science & Medicine Edition. 2005, 26(1): 20-22.

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  Damages existed in concrete structures after long-term working. Using the theory of wave propagation, aiming at several typical damaged models, the PST (pulse-spectrum technique) combined with regularization is adopted to inverse the damage by transient wave field in numerical simulations. The inversed result considering the priori information is made obviously better. The inversed results which basically agree with the real distribution of the damaged degree are gained.
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  A new method for determining optimal location of piezoelectric actuator/sensor

  WANG Feng, TANG Guo-jin, LI Dao-kui

  Journal of Jinan University Natural Science & Medicine Edition. 2005, 26(1): 23-25.

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  A new method for determining the optimal location of piezoelectric actuator and sensor are proposed. The piezoelectric structural dynamic equation is formed by finite element method and then transformed into lower dimension-alequation using modal subspace transformation, and the state space equation is established. The controllability matrices of the actuator input and the disturbance input are solved through Lyapunov equations, and the actuator controllability matrix is projected onto the disturbance controllability matrix to make a projection matrix. The optimal location of the actuator is obtained by maximizing the sum of squares of the length of the weighted column vectors in the projection matrix. Analogous method could be used to get the optimal location of the sensor.
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  Effect of defects on mechanical properties of cellular solids

  ZHANG Jun-yan, FU Yi-ming, ZHANG Ping

  Journal of Jinan University Natural Science & Medicine Edition. 2005, 26(1): 26-29.

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  The influence of defects on mechanical properties of cellular solids is studied in order to offering guidance for the design and manufacture techniques of this kind of material in some degree. The cell walls of cellular solids are considered in the abstract as elastic corrugated beams using continuum mechanics. The mechanical model containing both wavy cell wall and missing cell wall is established, and expressions of bulk modulus, shear modulus and elastic modulus varying with imperfections and relative density are derived. The results show that the bulk modulus, shear modulus and elastic modulus decrease remarkably with the increasing degree of wavy and the missing of cell wall.
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  Nonlinear dynamic behaviors of moderately thick laminated plates with damage and viscoelasticity

  ZHENG Yu-fang, FU Yi-ming

  Journal of Jinan University Natural Science & Medicine Edition. 2005, 26(1): 30-34.

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  The effects of damage on the nonlinear dynamic behavior of damaged viscoelastic laminated plates with a transverse periodic excitation are studied. Using the first order shear deformation theory, Boltzmann superposition principle and Galerkin technique, the nonlinear equations of antisymmetric cross-ply viscoelastic laminated plates with damage are derived. By numerical results, the effects of the damage on nonlinear dynamic behavior of visvoelastic laminated plates are discussed.
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  Convergence studies on the buckling analysis of beams by using the finite difference method

  LIU Ji-ke, YANG Yi

  Journal of Jinan University Natural Science & Medicine Edition. 2005, 26(1): 35-38.

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  The U-transformation and finite difference method are used in the study of (static,) buckling and dynamical analysis of structures. A buckling analysis is presented for a (simply) supported beam. The exact analytical solutions of buckling loads and the coefficients of the main error are obtained.
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  An improved method for general perturbation eigenvalue problems

  LIU Ji-ke, SUN Hui

  Journal of Jinan University Natural Science & Medicine Edition. 2005, 26(1): 39-42.

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  An improved perturbation method for general eigenvalue problems is presented. The proposed method is universally applicable to all the three cases of eigenvalue problems:distinct, repeated and nearly equal eigenvalues. The improvement is made to the orthogonal and normality condition and the solving condition of the eigenvector coefficient matrix adopted in the existing methods. Illustrative examples are given to demonstrate the precision of the improved technique.
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  Application of nonlocal lubrication model in cold extrusion

  YAN Xiao-qing, FU Ming-fu

  Journal of Jinan University Natural Science & Medicine Edition. 2005, 26(1): 43-45,56.

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  A model of nonlocal lubrication in cold extrusion is presented using the nonlocal friction law by Oden et. The approximate solution of the model is obtained by the perturbation method. The thickness and pressure of lubricant and force of friction are calculated by using this model.
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  Exact solutions of vibration analysis for stiffened plates

  CHAI Wei-si, LIU Feng

  Journal of Jinan University Natural Science & Medicine Edition. 2005, 26(1): 46-49.

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  Applying the U-transformation theory, an analytic solution is obtained for the dynamic response of stiffened plates with periodicity. An effective error analysis method of stiffened structures with continuous elastic supports is given.
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  Response analysis of X missile during road transportation and investigation of the vibration control system

  LI En-qi, TANG Guo-jin, LEI Yong-jun, LI Dao-kui

  Journal of Jinan University Natural Science & Medicine Edition. 2005, 26(1): 50-53.

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  A spring-mass computational model with three degrees of freedom is presented for the random response analysis during road transportation, and the quantity of joint stiffness between vehicle and missile is obtained. The 3-D FEM model of the vehicle and missile is established by MSC/NASTRAN to determine the design of the vibration system for a missile warhead by methods of random response analysis.
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  Buckling of a double-walled carbon nanotube under axial load

  LIANG Ying-jing, HUANG Xiao-qing, XIN Hao, HAN Qiang

  Journal of Jinan University Natural Science & Medicine Edition. 2005, 26(1): 54-56.

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  The effects of van der Waals forces between the inner and outer nanotubes and the elastic medium are taken into account. Using the beam theory a theoretical analysis model is presented for the buckling of a double-walled carbon nanotube under axial load. Based on the model, the critical buckling stress is derived.
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  A meshless local Petrov-Galerkin method for dynamic fracture problem

  LONG Shu-yao, LIU Kai-yuan

  Journal of Jinan University Natural Science & Medicine Edition. 2005, 26(1): 57-59.

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  The meshless local Petrov-Galerkin method(MLPG) is used to numerically find the solutions of a crack of finite specimen under a impact load. The moving least squares (MLS) technique in space and the center difference method in time are adopted in computation. Figures of the time history of the normalized stress intensity factor and stresses at a given moment are presented. Numerical examples show that the local Petrov-Galerkin method possessed an excellent rate of convergence and reasonably precision and it well have a great future in engineering.
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  Nonlinear buckling of sphere double-deck reticulated shallow shells

  LU Bao-hong, LIU Ren-huai

  Journal of Jinan University Natural Science & Medicine Edition. 2005, 26(1): 60-63.

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  Based on the nonlinear bending theory of double-deck reticulated shallow shells, the nonlinear buckling problem of sphere double-deck reticulated shallow shells under uniform transverse pressure is studied. An analytic solution for simply supported edges is obtained by using Galerkin's method. Numerical calculations are presented in diagrams to show the influence of geometrical parameters on the buckling behavior.
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  The structure integrity analysis of solid rocket motor grain with cohesive cavity

  MENG Shang-yang, TANG Guo-jin, YUAN Duan-cai, LEI Yong-jun

  Journal of Jinan University Natural Science & Medicine Edition. 2005, 26(1): 64-68.

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  Based on the structure integrity analysis of perfect solid rocket motor grain under internal pressure loading and axial acceleration loading, some positions are determined to presetting cohesive cavities in different strain grads of the rear motor grain. The three-dimensional viscoelastic finite element models of the motor grain with cohesive cavity are established. Under internal pressure loading and axial acceleration loading, the strain fields of the grain with cohesive cavity are studied. The maximum Von Mises strain of different regions and different diameter cohesive cavities are obtained. Then the allowable maximum diameter of the cohesive cavity could be determined by the maximum Von Mises strain criterion.
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  Establishing the damage developing equation of concrete through the principle of minimum dissipation of energy

  TANG Song-hua, LUO Ying-she, ZHOU Zhu-bao

  Journal of Jinan University Natural Science & Medicine Edition. 2005, 26(1): 69-71.

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  Taking concrete's isotropic elastic damage as example, this article puts forward a new thought of establishing the damage developing equation on the basis of the principle of minimum dissipation of energy, and infers the concrete's damage developing equation under uniaxial extension.
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  Numerical computation of buckling of a double-walled carbon nanotube under axial load

  XIN Hao, HAN Qiang, LIANG Ying-jing, HUANG Xiao-qing

  Journal of Jinan University Natural Science & Medicine Edition. 2005, 26(1): 72-73,97.

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  The effects of van der Waals forces between the inner and outer nanotubes and the elastic medium are taken into account. Using the elastic beam theory, numerical computation of buckling of a double-walled carbon nanotube under axial load is carried out.
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  A local Petrov-Galerkin (MLPG) method for the stability analysis of anisotropic thin plate

  XIONG Yuan-bo, LONG Shu-yao

  Journal of Jinan University Natural Science & Medicine Edition. 2005, 26(1): 74-76.

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  Using the moving least-square (MLS) approximation to interpolate solution variables and Kircihhoff's plate theory, the meshless local Petrov-Galerkin(MLPG) method is extended to solve the stability problems of anisotropic plates. In the analysis, the essential boundary conditions are enforced by a penalty method. The discrete eigenvalue problem is derived using the local integral symmetric weak form of the governing equation of the stability problem. Several examples, isotropic and symmetrically laminated composite plates, are given and compared with results via other methods to show that, the MLPG method has a number of advantages such as the quite good accuracy and high rate of convergence.
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  Research on dynamic response of flexible fiber reinforced concrete

  YAO Li-ning, ZHANG Fei-er, GUO Ren-jun, XIE Lin, HE Jun-yong, CHEN Xiang-xin

  Journal of Jinan University Natural Science & Medicine Edition. 2005, 26(1): 77-80.

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  The dynamic response of Carbon/Aramid fiber reinforced concrete is studied. Using the geometrical characteristic and force analysis in curved fiber in the concrete, the dynamic properties are derived for cantilever beam specimens made by flexible fiber reinforced concrete. Large deformation can be borne at the flexible fiber reinforced concrete. Energy loss of the concrete is increased and dynamic behavior is improved. Fiber hybridizing and curve angle of the flexible fiber reinforced concrete is very important for dynamic energy loss.
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  Seismic response analysis of base isolation high-rise building

  YUAN Bing, HUANG Yan-sheng, LI Li-juan

  Journal of Jinan University Natural Science & Medicine Edition. 2005, 26(1): 81-82.

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  In connection with a RC high-rise building, a 3-D finite-element model is used in seismic response analysis. The calculation results show that the aseismic behavior is excellent.
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  Tensile stress concentration and strength for notched unidirectional composites

  ZENG Qing-dun, HU Xiao-bing, XIE Shun-li, ZHANG Ning, WU Guang-chun

  Journal of Jinan University Natural Science & Medicine Edition. 2005, 26(1): 83-86.

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  By establishing a layering shear-lag model and using the statistical fracture theory of composites, the tensile stress concentrations and strengths for unidirectional composites with a central notch are studied. The stress concentrations and strengths obtained relatively coincide with the existing theory and experiments. The results show that the stress concentrations and strengths relate to the interfacial shear strength and the strengths are highest if the interfacial cohesion is suitable.
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  Wind velocity time-history numerical simulation theories in long-span spatial structures

  BIAN Jian-feng, WEI De-min

  Journal of Jinan University Natural Science & Medicine Edition. 2005, 26(1): 87-90.

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  Both considering time and spatial correlation, several stochastic wind field simulation methods are introduced for time-history analysis of spatial structures against wind load and the key algorithms involved are given. It is pointed out that the proper method should be adopted for different structures. Through a numerical example, some advice is given about the simulation parameters for the AR method.
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  Numerical simulation of drug distribution within the aorta and its branches

  QIU Lin, WU Xiao-ming, CEN Ren-jing

  Journal of Jinan University Natural Science & Medicine Edition. 2005, 26(1): 91-93.

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  Based on a 3-dimensional aorta-branch physical model established herein, under the pulsatile blood blow, the blood flow and liquid drug distribution within the aorta and its branches, while injecting liquid drug from aorta to its branches, are simulated numerically by using actual human body anatomic parameters. The periodic distribution of the blood dynamic parameters and the liquid drug density are obtained. The results are in accord with the modeling experiments properly.
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  Application of 3-dimensional H-adaptive error estimation in welding engineering

  YU Xue-jin, ZHANG Shao-qin, PENG Ying-feng

  Journal of Jinan University Natural Science & Medicine Edition. 2005, 26(1): 94-97.

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  A posteriori error estimation method which works in tandem with finite element analysis and adaptive mesh management is presented. It can be used to compute many appropriate scalar quantities such as temperature, displacement, effective stress and effective plastic strain.
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  Constitutive model of rubber-like materials with significant hardening at large strains

  ZHU Yan-feng, LIU Feng, HUANG Xiao-qing, LI Li-juan

  Journal of Jinan University Natural Science & Medicine Edition. 2005, 26(1): 98-99,102.

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  Many rubber-like materials exhibit a significant stiffening or hardening in their stress-strain curves at large strains. A strain-energy function is applied to model this strain hardening effect in isotropic hyperelasticity incompressible rubber-like materials. The strain-energy function involves a constraint on the strain invariants and limits the maximum stretch. Then the homogeneous deformation of uniaxial extension is examined. A simple experiment is done to convey the usefuless of proposed method. It is shown that this function can reflect the hardening effect on Mooney-Rivlin materials.
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  The prestress loss of presstressed steel bar caused by friction between the bar and its hole wall

  WANG Hong

  Journal of Jinan University Natural Science & Medicine Edition. 2005, 26(1): 100-102.

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  The prestress losses of presstressed steel bar caused by friction between the bar and its hole wall are studied by theoretical analysis and experimental research. Measurements for reducing the prestress losses in constructing process are brought forward.
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  Calculated analysis for steel sheet pile foundation layer

  LI Guang-fan

  Journal of Jinan University Natural Science & Medicine Edition. 2005, 26(1): 103-106.

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  The purpose of this research is to develop computational procedures for nonlinear soil-structure interaction problems. In order to study soil-structure interaction behavior, the finite element analysis for the strip footing subjected to both vertical and lateral loads, and foundation layer reinforced with sheet pile are considered. Interface elements are used between the footing and the soil to model the interface behavior. The main analyzed results are as follows; (1) For the prediction of settlement and lateral displacement, the result due to interface element is evaluated larger then without interface element. (2) For the determination of ultimate bearing capacity, the value using interface element appeared smaller by 12%, which is safe. (3) The horizontal and vertical displacement of a strip footing affected by the presence of interface element.
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  Analysis on influencing factors to deflection of slab with cavity

  TANG Li-qun, HU Zhe, LIU Yi-ping, HUANG Xiao-qing

  Journal of Jinan University Natural Science & Medicine Edition. 2005, 26(1): 107-109,113.

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  The influencing factors to suspending rigid plate are investigated by three-dimensional finite element analysis. The investigation places emphasis on the contribution of the dimension of suspending. In the analysis, the differential factors between the results of finite element analysis and theoretical analysis on no-suspending plate are studied first. The optimal dimension in the finite element analysis is determined. Based on this, the rigid flexure, including its variation with the change of the dimension of suspending, is analyzed by finite (element) analysis. The measuring results of flexure in an engineering case are presented in the end. The analysis results show that the measurement of flexure can be used to judge the existence of suspending plate, but it is not an overall judgment, other measuring methods shall be supplied.
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  Preliminary research on the cause of the cracks in thin-walled flexible piers of continuous rigid frame bridges

  LIANG He-xing, HE Ting-hui, LAO Xiao-chun, TANG Li-qun

  Journal of Jinan University Natural Science & Medicine Edition. 2005, 26(1): 110-113.

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  Through the investigations on the distribution of cracks in thin-walled flexible piers of built continuous rigid frame bridges, and mechanics analysis on a thin-walled flexible pier of a building continuous rigid frame bridge, the cause of the cracks on the piers is derived preliminarily. The researches show that the vertical cracks on the surfaces paralleled to water flow of thin-walled flexible piers may be induced by the large shear stresses at the faceoffs in the cross-section near the bearing and the variable cross-section of the pier.
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  Statistics analysis and simulation of random loads for bridges

  ZHENG Xiao-hong, HUANG Pei-yan, YAO Guo-wen, ZHAO Chen, HUANG Long-tian

  Journal of Jinan University Natural Science & Medicine Edition. 2005, 26(1): 114-116.

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  Considering the distribution function and power density function of random process, our research uses the non-Gaussian data simulation process to represent those vehicles loads mentioned before. The result proves that this method can realize the transform from traffic flux in time plane to frequency plane. That is the traffic flux transform from time domain to frequency domain.
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  Study on fatigue characteristics of steel fiber reinforced and polymer modified concrete

  LIU Yi-ping, HUANG Xiao-qing, TANG Li-qun, LUO Li-feng

  Journal of Jinan University Natural Science & Medicine Edition. 2005, 26(1): 117-119.

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  The fatigue behavior of a kind of new cement concrete bridge deck pavement material-Steel Fiber Reinforced and Polymer Modified Concrete (SFRPMC) is studied. Equal amplitude fatigue experiments are carried out on three-point bending samples. Single-log fatigue equation S-lgN is derived. The differences of the bending fatigue properties between Steel Fiber Reinforce Concrete (SFRC) and SFRPMC are compared and analyzed. The results show that the SFRPMC exhibit better fatigue behavior than SFRC.
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  Effect of thickness of carbon fiber laminateon load carrying capacity of strengthened RC beams

  YAO Guo-wen, HUANG Pei-yan, ZHENG Xiao-hong, ZHAO Chen, CHEN Cui-feng

  Journal of Jinan University Natural Science & Medicine Edition. 2005, 26(1): 120-122,144.

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  Effect of thickness of carbon fiber laminate (CFL) on failure modes and load carrying capacity of strengthened RC beams is probed by three point bending experiments. The failure procedure of RC beam is dominant by concrete cracking and steel bar yielding. But CFL strengthened RC beams fail with CFL debonding from concrete and then fracture, CFL debon-(ding) from middle span to end and concrete crushing with increasing thickness of bonded CFL. The ultimate load capacity of strengthened RC beams is higher with thicker externally bonded CFL, which increases from 12.6% to 38.9% than that of RC beams.
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  Effect on the deformation of the body of coke drums due to the ascending of supports

  ZHU Yong-an, WANG Fan, LIU Ren-huai

  Journal of Jinan University Natural Science & Medicine Edition. 2005, 26(1): 123-126.

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  The deformation effect of the body of coke drums due to ascending of supports is studied by using finite element method. Whether the problem of bulge can be solved due to ascending of supports is discussed by comparing with the deformation when the supports are in the former location. Three kinds of load conditions are calculated in one operating circle. It is concluded that, the radial deformation can not be decreased remarkably due to the ascending of supports.
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  Application of the supersonic method in stake inspection by reflective waves

  CHEN Yi-bai

  Journal of Jinan University Natural Science & Medicine Edition. 2005, 26(1): 127-129.

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  Some defects in the measurement of length of a stake and in acquirement of strength grade of the concrete in a stake are discussed. It is brought forward that the accuracy of wave velocity of a stake can be improved by measuring the supersonic velocity of the head of it. According to the result of a practical measurement, this method can be effectively applied to practical engineering.
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  Theoretical aspects of edge singularity at surface cracks

  K. T. Chau

  Journal of Jinan University Natural Science & Medicine Edition. 2005, 26(1): 130-133.

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  The complicated issue of the so-called vertex singularity near the corner point of the intersection of a three-dimensional crack front and the free surface of the solid are reviewed and discussed. It was discovered that classical stress singularity near a crack front of r^-0.5 (where r is the distance measure from the crack tip) does not hold at the edge of the crack at the free surface, but instead of the form r^λ. The exponent λ is a function of mode of cracking (i.e. mode Ⅰ, Ⅱ or Ⅲ), the inclination angle β of the crack front at the free surface, the inclination angle γ of the crack plane with the solid surface and the Poisson's ratio of the solid. Analytical results exist only for very special cases, whereas most existing results were obtained through the use of very fine mesh finite element method, finite difference and hypersingular integral equation. Although the vertex singularity is of paramount importance in engineering application, these results were not readily available in the handbooks of stress intensity factor. Therefore, the main purpose of this paper is to summarize this importance results in a form that can be easily used by engineers and scientists.
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  Numerical analysis for BHA

  YANG Dong-quan

  Journal of Jinan University Natural Science & Medicine Edition. 2005, 26(1): 134-136.

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  Theory of finite element method and finite difference method for BHA are briefly discussed. Applying the computer calculation programs using above methods, side forces at bit are obtained and compared. The results verify the accuracy of both methods.
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  Finite-element analysis for static deformation of drill pipes

  YANG Dong-quan

  Journal of Jinan University Natural Science & Medicine Edition. 2005, 26(1): 137-140.

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  Static deformation of drill pipes is discussed by using finite element method. Basic finite element technique for analyzing is described, including discretization and interpolation, forming of stiffness matrix and external force vector, solution for contact and nonlinear problem, etc.. As application, side forces at bit are calculated and analyzed for some typical BHA and drilling parameters.
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  Direct calculation for fatigue strength analysis of ship structures

  CHEN Chao-he

  Journal of Jinan University Natural Science & Medicine Edition. 2005, 26(1): 141-144.

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  According to the facts that some ships such as contain ships with very large flare suffer the non-linear wave induced loads, a method of direct calculation for fatigue strength analysis of ship structures is put forward. In the analysis, the non-linear wave loads should be included. Calculation results show that nonlinear factors are important for fatigue strength analysis of ship structures.