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EFFECTS OF VISCOSITY ON EQUATION OF MOTION AND CRITICAL FLOW VELOCITY OF FLUID-CONVEYING PIPE
Mechanics in Engineering    2010, 32 (5): 10-13.   DOI: 10.6052/1000-0879-lxysj2009-406
Abstract1388)      PDF(pc) (690KB)(537)       Save
Considering the non-uniformity of the flow velocity distribution in a fluid-conveying pipe caused by the viscosity of real fluid, the centrifugal-force term in the equation of motion of the pipe is modified in the cases of laminar flow and two modes of turbulent flow. The modification factors are found to be 1.333, 1.020 and 1.037$\sim$1.055 for laminar flow in circular pipe, turbulent flow in smooth circular pipe and turbulent flow in rough circular pipe, respectively. The critical flow velocities for divergence in the above-mentioned three cases are found to be 13.4{\%}, 1.0{\%} and 1.8\%$\sim$2.6{\%}, respectively, lower than those for ideal fluid flow. The effects of fluid viscosity on the equation of motion and the critical flow velocity of fluid-conveying pipe are explicitly related to the flow mode only. The viscosity coefficient plays an implicit role via Reynolds number, which determines the flow mode.
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Cited: Baidu(4)
EXPERIMENTAL STUDY OF PERMEABILITY IN FRACTURED SANDSTONE WITH SEDIMENT PARTICLES
Mechanics in Engineering    2010, 32 (5): 14-17.   DOI: 10.6052/1000-0879-lxysj2010-050
Abstract1269)      PDF(pc) (1402KB)(451)       Save
Sediment particles in natural rock with a large number of connected cracks and faults, have some impact on the transport of groundwater and the variable permeability by creating micro-cracks and damage zones around faults. In this paper, an experiment about seepage on the rock electro-hydraulic servo test system of MTS815.02, together with electron micrograph of sandstone pore, is designed and used to investigate the relationship between the variable permeability and the filling silt in creating cracks. Results show that the permeability in cracked rock decreases distinctly under the silt-induced effect. The permeability, along with the sediment particles in macro-fissures in the cracked rock to achieve re-balancing of transport, gradually increases over time and eventually stabilizes.
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Cited: Baidu(5)
INFLUENCE OF RELATED FACTORS ON WELLHEAD TEMPERATURE IN MECHANICAL RECOVERY WELL
Mechanics in Engineering    2010, 32 (5): 18-21.   DOI: 10.6052/1000-0879-lxysj2009-233
Abstract1480)      PDF(pc) (611KB)(613)       Save
The physical property and rheological behavior parameters of the flow in the wellbore are sensible functions of temperature. It is of fundamental importance to calculate the temperature field for the optimization design of an oil/gas production scheme. Based on the thermal conduction theory, a mathematical model is formulated for the temperature calculation of the wellbore for mechanical recovery wells. The influences of such factors as the well yield, water content, well depth, pipe radius, ambient temperature and geothermal gradient, on the wellhead temperature are investigated.
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Cited: Baidu(1)
ANALYSIS OF NONLINEAR STABILITY OF DOUBLE-DIFFUSIVE CONVECTION WITH CROSS-DIFFUSION IN A THERMOHALINE SYSTEM
Mechanics in Engineering    2010, 32 (5): 22-26.   DOI: 10.6052/1000-0879-lxysj2010-187
Abstract1312)      PDF(pc) (804KB)(416)       Save
In this paper, the nonlinear stability of double-diffusive convection with cross-diffusion in a thermohaline system is analyzed. By using a simple expression, the nonlinear equations are solved. By expressing two cross-diffusive coefficients by two parameters, a more general $R_T$-$R_S$ relation and expressions of steady finite amplitude are obtained. These expressions can be reduced to those previously-derived ones when both cross-diffusive coefficients are equal to zero.
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Cited: Baidu(2)
THE FLOW AND INTERNAL LEAKAGE OF ANNULAR SPIRAL FLOW IN HYDRAULIC ROTARY ACTUATOR
Mechanics in Engineering    2010, 32 (5): 27-30.   DOI: 10.6052/1000-0879-lxysj2010-078
Abstract1294)      PDF(pc) (1087KB)(567)       Save
Considering that the viscosity of the hydraulic oil will change accordingly when the temperature and pressure vary, the flow rate equation and leakage rate equation of the annular spiral flow in Hydraulic Rotary Actuator are derived based on continuity equation, N-S equation and energy equation. Using the CFD simulation software ``Fluent'', the flow field and the leakage law of the internal annular spiral flow are simulated. Comparing the simulation results with the theoretical calculation of the flowing annular spiral flow, the theoretical analysis is verified, which may provide a theoretical basis for studies of internal leakage and volume depletion in Hydraulic Rotary Actuator.
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Cited: Baidu(3)
THE SEISMIC RESPONSE OF PILES IN WAVE-CURRENT FIELD
龚维明 and 戴国亮
Mechanics in Engineering    2010, 32 (5): 31-35.   DOI: 10.6052/1000-0879-lxysj2010-033
Abstract1027)      PDF(pc) (1449KB)(454)       Save
The seismic responses of the piles in a wave-current field are studied by theoretical analysis and finite element simulation. Besides the wave-current force and hydrodynamic pressure on the piles in the wave-current field, the results of the model test show that the vortex-induced lateral force should also be considered. The finite element simulation of a platform with four piles in the wave-current field under seismic action is carried out. It is shown that the seismic responses of the piles are magnified by water. Except for the acceleration along piles, the relative displacement and shear force and moment are increased significantly under the combined action of the wave-current force and the vortex-induced lateral force. And it is also indicated that the failure at the bottom of piles occurs easily under the seismic action.
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SETTLEMENT ANALYSIS OF ADJACENT BUILDINGS INDUCED BY THE WATER PRECIPITATION OF RIVER CONSTRUCTION
文其云
Mechanics in Engineering    2010, 32 (5): 41-44.   DOI: 10.6052/1000-0879-lxysj2010-019
Abstract1191)      PDF(pc) (667KB)(477)       Save
Based on the sedimentation calculation of foundation and the practical observation of basic sedimentation, the analyses are made of the influence of precipitation of river construction on the adjacent buildings. The result shows that the subsidence of the buildings and cracks are due to the precipitation water in the construction; the foundation settlement of adjacent buildings decreases from near region to far region of the construction site of precipitation; an effective way is to combine the water curtain with the recharge well to control the decrease of the groundwater level.
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ANALOGOUS TRANSFORMATION OF STATIC AND DYNAMIC SOLUTIONS BETWEEN FUNCTIONALLY GRADED MATERIAL BEAMS AND UNIFORM BEAMS
Mechanics in Engineering    2010, 32 (5): 45-49.   DOI: 10.6052/1000-0879-lxysj2010-031
Abstract1447)      PDF(pc) (901KB)(489)       Save
Based on the theory of Euler-Bernoulli beams, the bending, buckling and free vibration of functionally graded material (FGM) beams were analyzed. By comparing the governing equations of functionally graded material beams and uniform beams, an analogous transform relation between the solution of FGM beam and that of uniform beam were obtained. If the material properties of FGM beam can be expressed in power functions in the lateral direction, the transformation factors between the solutions of the two kinds of beams were derived in analytical forms, which reflect the non-uniform properties of the functionally graded material beams. Therefore, the solution of static and dynamic problems of FGM beams can be transformed to that of a uniform beam and the calculation of the transformation factors under the same loadings and boundary conditions. This method can provide a simple and convenient approach in analysis of non-uniform beams and find applications in engineering.
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Cited: Baidu(12)
THE INFLUENCE OF THE CONFIGURATED PARAMETERS OF CONCRETE COMPOSITE TARGET ON THE PENETRATION DECELERATION
Mechanics in Engineering    2010, 32 (5): 55-61.   DOI: 10.6052/1000-0879-lxysj2010-034
Abstract1091)      PDF(pc) (2112KB)(427)       Save
The important parameters for the concrete composite target to simulate the monolithic target include the number of matrix layers and thicknesses of adhesive layers of the concrete composite target. The influence of the two parameters on the penetration deceleration is studied by using AUTODYN2D hydrocode. The calibration and validation for the initial simulation model and material parameters are done through a comparison of numerical simulation results with the experimental results and the analytical model in literature. Multi-group simulation models of the concrete composite targets subjected to projectile impact are configured based on the number of matrix layers and thicknesses of adhesive layers of composite targets. The results of penetration velocity and deceleration-time histories show that the composite target can simulate the monolithic target in the deceleration penetration experiments, but the thicknesses of adhesive layers should not be more than half of the projectile nose length, the deviation between them increases as the number of matrix layers of composite target increases when the thicknesses of adhesive layers are more than half of the projectile nose length. The simulation results provide references for the configuration of concrete composite targets in trials.
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Cited: Baidu(1)
ANALYSIS OF LATERAL BEARING CAPACITY OF RIGID ROOT-FOUNDATION
龚维民,殷永高,童小东 and 单建
Mechanics in Engineering    2010, 32 (5): 67-71.   DOI: 10.6052/1000-0879-lxysj2008-458
Abstract1004)      PDF(pc) (737KB)(452)       Save
Based on the Winkler beam theory, the working mechanism and the bearing capacity of a lateral-loaded root-foundation are investigated, with a model of calculation. The elastic solution of the lateral-loaded root-foundation is obtained by using the load transfer method. The lateral bearing capacity is calculated, and the distributions of the lateral displacement, flexural moment, shear force and soil resistance of the root-foundation are obtained. The results show that the lateral bearing capacity of the root-foundation is better than the traditional caisson foundation, with the top lateral displacement being reduced by 35%~45% and the lateral bearing capacity being increased by 45%~55%. The calculated results are in good agreement with the test results in the elastic range, therefore, the load transfer method can be applied in the engineering calculation of root-foundations.
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Cited: Baidu(2)
REAL-TIME COMPUTATION OF MOMENT OF INERTIA AND DAMPING RATIO
Mechanics in Engineering    2010, 32 (5): 72-75.   DOI: 10.6052/1000-0879-lxysj2010-072
Abstract1185)      PDF(pc) (688KB)(518)       Save
In this paper, taking the prolate cycloid-three-wire as a model of physical dynamics, we consider the damping's influence on computation of workpiece's moment of inertia by using the second kind Lagrange's equation. It is difficult to calculate the value of amplitude of swing accurately by the amplitude measuring method. So, an equal arc length- time ratio method is proposed to improve the precision for a workpiece of large size. The damping ratio $\zeta $ is obtained by calculating the time ratio of hanging dish which swings beyond the equal arc length in the same location with different periods.
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Cited: Baidu(2)
NUMERICAL SIMULATION OF RELATIONSHIP BETWEEN HYDRAULIC CONDUCTIVITY AND POROSITY SIZE FOR POROUS GEOTECHNICAL MATERIALS
李守巨,刘迎曦,孙伟 and 吴金花
Mechanics in Engineering    2010, 32 (4): 12-17.   DOI: 10.6052/1000-0879-lxysj2009-404
Abstract1646)      PDF(pc) (4207KB)(504)       Save
The relationship between hydraulic conductivity of a porous material and its number-size is simulated by using the finite element method. The solid matrix and the pore space are generated randomly according to the material porosity, and the material parameters and the element properties are assigned by the ANSYS parameter design language. The equivalent hydraulic conductivity is computed according to the flow flux through some section computed by FEM and Darcy law, and the relationship between the equivalent hydraulic conductivity and the porosity number-size of porous materials is obtained. The numerical simulation shows that the equivalent hydraulic conductivity is directly proportional to the square of the porosity size while the porosity is constant, for which the proposed conclusion agrees well with empirical expressions. The equivalent hydraulic conductivity is directly proportional to the porosity while the porosity size is constant.
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Cited: Baidu(14)
NUMERICAL SIMULATION OF TIME-AVERAGED WIND FORCES ON TWO CYLINDERS OF UNEQUAL-DIAMETER AT HIGH REYNOLDS NUMBER
Mechanics in Engineering    2010, 32 (4): 18-21.   DOI: 10.6052/1000-0879-lxysj2009-248
Abstract1085)      PDF(pc) (718KB)(462)       Save
The aerodynamic interference between cylinders is a topic of great theoretical and practical significance. Though some wind tunnel tests related to wind pressure distribution on cylinders complex have been carried out at home and abroad, only cylinders of equal-diameter and Reynolds number below 10$^{5}$ are considered. However, actual engineering structures are often immersed in wind flows of high Reynolds number. This paper studies the time-averaged flow at high Reynolds number ($Re=4.5\times 10^{5})$ around two cylinders of unequal-diameter, combined in tandem, side-by-side and in staggered styles, which is simulated by numerical methods, for various spacings and wind directions. The time-averaged drag, lift and resultant wind forces on two cylinders are obtained and analyzed. Which may serve as a reference for wind-resistant design for similar structures.
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AN EXPERIMENTAL STUDY ON INTERACTION OF ENERGETIC GAS JET AND LIQUID
Mechanics in Engineering    2010, 32 (4): 22-26.   DOI: 10.6052/1000-0879-lxysj2010-011
Abstract1226)      PDF(pc) (3042KB)(411)       Save
In order to study the control of the combustion stability of the bulk-loaded liquid propellant gun (BLPG), a simulating equipment of ignition and injection of the BLPG and four kinds of stepped-wall chambers were designed. A high speed digital video system was used to observe the expansion process of the energetic gas jet in a liquid simulating medium. The congestion phenomenon in the experiment was analyzed. Results show that the jet expansion process in the stepped-wall chamber is stable and the injection pressure, the nozzle diameter and the stepped-wall geometry have a remarkable influence on the jet expansion and the mixing process of gas and liquid, so the jet expansion process can be controlled effectively by adjusting these parameters. The congestion of the nozzle causes dissymmetric jet expansion and affects the mixing process, so that it is unfavorable for controlling the jet stability.
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Cited: Baidu(5)
LOAD TRANSFER MECHANISM OF BONDED REBARS WITH FULL-LENGTH BONDING
Mechanics in Engineering    2010, 32 (4): 27-29.   DOI: 10.6052/1000-0879-lxysj2009-506
Abstract1157)      PDF(pc) (530KB)(398)       Save
Using basic assumptions and solutions of spatial axisymmetric problems of elasticity and the shear displacement method, an analysis model is proposed and the basic equations, are deduced with analytical solutions, which illustrate the attenuation curve with an example, together with the load transfer coefficient $k$ and its influence on the load transfer law.
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Cited: Baidu(1)
THE EFFECT OF CAPROCK PERMEABILITY ON THE LEAKAGE OF CO_2 IN A CO_2 CAPTURE AND STORAGE PROJECT
Mechanics in Engineering    2010, 32 (4): 30-34.   DOI: 10.6052/1000-0879-lxysj2009-457
Abstract1013)      PDF(pc) (1120KB)(411)       Save
The leakage after CO_2 sequestration is critical in the evaluation of CO_2 storage period and the stability of the cap-rock. In this paper, the commercial FEM software ABAQUS is used with a secondary development to analyze the key factors of CO_2 seepage. Meanwhile the gas Vander-Walls equation is applied to the supercritical CO_2 compared to the ideal gas equation. A simple theoretical result is obtained and verified in a good agreement with that of simulation. The results show that at least 150 000 years are needed until CO_2 escapes completely from a homogeneous cap-rock with a low permeability; the number storage duration is decreaseds to 10 000 years when there is a high permeability leaky well or fractures, hence, fractures or leaky wells should be consolidated before sequestration or kept away from project areas.
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Cited: Baidu(7)
CIRCUMFERENTIAL BENDING DEFORMATION OF CYLINDRICAL SHELL UNDER LINEAR LOAD
潘存云,王荣吉
Mechanics in Engineering    2010, 32 (4): 35-39.   DOI: 10.6052/1000-0879-lxysj2009-395
Abstract1559)      PDF(pc) (1303KB)(506)       Save
With the displacement function expressed in single trigonometric series, the circumferential bending problem of the cylindrical shell under arbitrary normal distributed load and simply supported in the opposite edges, is solved. Approximately taking the distributed load as a linear load in the infinitesimal rectangle region, the circumferential bending deformation formula of the cylindrical shell under the linear load is deduced. The special formula is obtained when the linear load is uniformly-distributed and linearly varying. The results show that, under given boundary constraints, the displacement distribution of the cylindrical shell circumferential bending deformation calculated by the theoretical method is consistent with that calculated by FEA.
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DYNAMIC RESPONSE OF A TIMBER STRUCTURE WITH HIGH-PLATFORM FOUNDATION UNDER TRAFFIC LOADS
刘增荣
Mechanics in Engineering    2010, 32 (4): 40-46.   DOI: 10.6052/1000-0879-lxysj2009-463
Abstract1249)      PDF(pc) (2312KB)(437)       Save
The timber structure with high-platform foundation is the main form of historic buildings in China, such as bell tower and drum tower. Taking Xi'an Bell Tower as an example, a three-dimensional finite element model of the bell tower-soil-tunnel structure interaction is built, and the dynamic response of the bell tower under simulated metro-induced loading is obtained by means of dynamic finite element analysis. The vibration response of the bell tower under ground traffic loads were obtained through all-weather field monitoring. These two results are combined by using the SRSS method to obtain the response of the timber structure of the bell tower under combined action of ground and underground traffic loadings. The structure may be evaluated according to the technical specifications, the results may serve as a reference for dynamic response analysis and assessment of similar historic buildings under traffic loads.
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Cited: Baidu(2)
ANALYSIS OF EARTHQUAKE EFFECT FOR FRAMES BY THE METHOD OF REVERBERATION RAY MATRIX
陈科夫,孙国钧 and 赵社戌
Mechanics in Engineering    2010, 32 (4): 47-50.   DOI: 10.6052/1000-0879-lxysj2009-479
Abstract1225)      PDF(pc) (692KB)(453)       Save
Transient response analysis of structures under seismic load is important in a seismic design. Most earthquake effect studies use time domain numerical integration methods. The method of reverberation ray matrix is a novel frequency domain matrix method for transient analysis of trusses and frames. Based on Bernoulli beam theory, the present work extends the reverberation ray matrix method to the case of ground acceleration loads. The calculation of a piece of steel frame subjected to the ground El Centro acceleration wave demonstrates that the method can be used to analyze the earthquake effect of structure accurately and effectively.
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Cited: Baidu(1)
BUCKLING MODE FUNCTION OF STAYED STEEL COLUMN
Mechanics in Engineering    2010, 32 (4): 51-57.   DOI: 10.6052/1000-0879-lxysj2010-006
Abstract1148)      PDF(pc) (905KB)(521)       Save
The mode function is the key for obtaining the critical load of a stayed steel column. Based on two basic modes, symmetric and anti-symmetric, the basic buckling mode functions are obtained, and three examples are considered for the performance of simulation curves by varying their key parameters. At last, the buckling mode function for asymmetric buckling is obtained. The results indicate that the engineering requirements can be met when the number of simulation curves is equal to the total section number of the stayed steel column.
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Cited: Baidu(1)
THE METHOD OF CENTROID LUMPED MASS IN THE FINITE ELEMENT
Mechanics in Engineering    2010, 32 (4): 58-61.   DOI: 10.6052/1000-0879-lxysj2009-407
Abstract1124)      PDF(pc) (834KB)(492)       Save
The lumped mass at the centroid will gives more accurate results for dynamic problems, and also make it possible to optimize the element inertia effect and improve the matching between the element inertia and deformation effects. The detailed analyses of the frequency-dispersion effect for a one-dimensional problem shows the validity of the method.
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Cited: Baidu(1)
RELIEVING STRESS BY VIBRATORY STRESS RELIEF IN THE HT-7U VACUUM ROOM
Liu Longfei,陈立功 and 倪纯珍
Mechanics in Engineering    2010, 32 (4): 62-65.   DOI: 10.6052/1000-0879-lxysj2009-025
Abstract1184)      PDF(pc) (1019KB)(576)       Save
The vibratory stress relief (VSR) process works in a cyclic creep mechanism. To deal with the distortion in the welding of the HT-7U vacuum room, the residual stresses are eliminated in the welding place by a VSR process, to improve the size precision of the vacuum room. With an an analysis of dynamic stresses and the measurements of residual stresses before and after the VSR process, the reduction and redistribution of residual stresses can be evaluated. The experimental results show that the VSR process is effective.
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Cited: Baidu(2)
COMPOSITE IMPLICIT TIME INTEGRATION METHOD FOR DYNAMIC EQUATIONS WITH NONLINEAR DAMPING
Mechanics in Engineering    2010, 32 (4): 66-70.   DOI: 10.6052/1000-0879-lxysj2009-348
Abstract1220)      PDF(pc) (764KB)(449)       Save
The direct time integration methods for nonlinear dynamic equations are based on a relationship of state variables between the time of $t$ and $t+\Delta t$, and the nonlinear dynamic equations can be converted into a set of nonlinear algebraic equations, to be solved with Newton-Raphson or BFGS iterations during each time increment. The composite implicit time integration method proposed by K. J. Bathe is deduced for dynamic equations including nonlinear damping, in which the velocity is taken as the basic variable in this paper. Sdof system with fluid viscous dampers is taken as an example, and Fortran programs are developed according to above iteration procedure and Newmar $k$-$\beta $ algorithm based on BFGS iteration for the Sdof system. Results are compared with that of Adina, and the accuracy is valieated.
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WAVELET-DQ METHOD FOR LONGITUDINAL VIBRATION ANALYSIS OF ELASTIC STRAIGHT ROD WITH VARIABLE CROSS-SECTION
Mechanics in Engineering    2010, 32 (4): 71-73.   DOI: 10.6052/1000-0879-lxysj2009-267
Abstract1197)      PDF(pc) (467KB)(519)       Save
The wavelet-DQ method combines the classic differential quadrature (DQ) method, the multi-resolution analysis theory, and a constructor of scaling function-based interpolation base functions. This is a new method for solving boundary value problems of differential equations. This method is applied to analyze the longitudinal vibration of an elastic straight rod with variable cross-section, to obtain the frequency equation. With different parameters, the natural frequencies of clamped-clamped, free-free wedge-shaped straight rod and cone-shaped straight rod are obtained. Numerical results show that the method is simple and enjoys high-precision. This method can be applied to other mechanical problems in numerical analysis.
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Cited: Baidu(3)
THE MESHLESS METHOD FOR UNSTEADY FLOW WITH MOVING BOUNDARY
ZHOU Xing XU Houqian
Mechanics in Engineering    2010, 32 (3): 16-21.   DOI: 10.6052/1000-0879-2009-344
Abstract1356)      PDF(pc) (901KB)(582)       Save
The meshless method is used to solve problems with moving boundaries, A method is proposed for dealing with unsteady flow with movable and torsional boundaries in small scale. The moving principle for discrete points in meshless method is formulated, the spring analogy is modified to consider the movements of points, the adaptability and precision of the analogy are enhanced. ALE equations are solved based on meshless method. Based on clouds, the spatial derivatives are approximated by using local least-squares curve fitting and the numerical flux is calculated with HLLC scheme, a multistage Runge-Kutta algorithm is used to advance the equation in time. The oscillating flow of representative airfoils in transonic and supersonic conditions is simulated. The computational results agree well with the experiment data, which indicates that the method is valid.
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A FCBIS TRIANGULAR ELEMENT FOR INCOMPRESSIBLE FLUID FLOWS
HAN Xiangke SU Bo
Mechanics in Engineering    2010, 32 (3): 22-25.   DOI: 10.6052/1000-0879-2009-308
Abstract997)      PDF(pc) (716KB)(523)       Save
Taking advantages of the best features of flow-condition-based interpolation and split scheme, this paper proposes a flow-condition-based interpolation split scheme (FCBIS). A two dimensional triangle fluid element is built and a corresponding program is developed. The solution procedure is discussed and the numerical example solution is given to illustrate the efficiency and accuracy of the procedure.
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Cited: Baidu(2)
THE NUMERICAL STUDY OF INFLUENCE OF BODY SHAPE ON CARANGIFORM
JING Jun XU Jian LIANG Zhonggang
Mechanics in Engineering    2010, 32 (3): 26-30.   DOI: 10.6052/1000-0879-2009-236
Abstract1060)      PDF(pc) (1736KB)(631)       Save
The carangiform propulsion has been paid much attention in recent years. In nature, the fish may have many kinds of tail shape, but only a few body shapes. This paper studies the influence of the body shape on the carangiform propulsion. Two body models are used in numerical simulation: model A, the fish normal body shape; model B, the submarine shape. The tail takes a crescent shape. The strouhal number ($St$) is chosen as the main parameter, and the combined translational-rotational oscillations are taken as the motion of tail. The hydrodynamical force is calculated by the software FLUENT. The results show that the body shape does affect the carangiform propulsion, the fish body shape is beneficial to cruising as a result of the nature evolutional selection.
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A KIND OF CONSTITUTIVE MODEL OF TiNi IMPORTED TO ABAQUS
DENG Shichun HU Xiuzhang LI Yongchi
Mechanics in Engineering    2010, 32 (3): 31-34.   DOI: 10.6052/1000-0879-2009-279
Abstract1393)      PDF(pc) (640KB)(889)       Save
Tang's model was simplified and extended to three dimensional space based on the assumption in plasticity theory. A user defined material subroutine (UMAT) is developed for ABAQUS application. Simulations for quasi-static tensile experiments with the pseudoelastic TiNi alloy specimen are conducted and the results agree well with the experimental data.
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QUANTITATIVE RESEARCH ON PLASTIC DEFORMATION AND DAMAGE IN STEEL MEMBER BASED ON DIFFUSE-REFLECTANCE METHOD
LIU Yu LI Zhaoxia HUANG Yueping ZHOU Sheng
Mechanics in Engineering    2010, 32 (3): 35-40.   DOI: 10.6052/1000-0879-2009-226
Abstract1180)      PDF(pc) (1218KB)(573)       Save
This paper proposes a method for quantitative testing of plastic deformation and damage in steel members during the process of loading. The Diffuse-Reflectance Method was used to obtain varied images of surface roughness of steel specimen during the process of stretching. With a further treatment of these images, the average gray value variations can be obtained to reflect the steel specimen surface roughness, which will help us to find out the sensitive parameter relevant to plastic deformation and damage status in the steel member under loading. The results show that, based on Diffuse-Reflectance Method and image processing, the average gray value variations of steel specimen's surface roughness during the loading process could be used to detect the start of plastic deformation and to describe the damage degree quantitatively in the late stage of plastic deformation of metal components or structures.
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Cited: Baidu(2)
NUMERICAL CALCULATION OF THE POST-BUCKLING CONFIGURATION OF A COLUMN UNDER DISTRIBUTED LOAD
LI Qing-Lu LI Shirong
Mechanics in Engineering    2010, 32 (3): 41-43.   DOI: 10.6052/1000-0879-2009-384
Abstract1478)      PDF(pc) (412KB)(566)       Save
The buckling and post-buckling behaviors of a column under distributed load are discussed in this paper. Based on the large deformation theory and considering the axial extension of the column, the equilibrium equations with geometric nonlinearity of an elastic column subjected to distributed load are established. By using shooting method and analytical continuation, the nonlinear boundary-value problem is solved numerically. The post-bucking configuration and equilibrium paths of the column are obtained.
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Cited: Baidu(2)
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