共查询到20条相似文献，搜索用时 31 毫秒
1.
Based on the fluid saturated biphasic porous media model deduced from mixture theory,a finite element formulation with u S u F p variables for dynamic response analysis is given out.This method overcomes the difficulty of choosing suitable penalty parameter in penalty finite element method,and the accuracy of pressure distribution obtained with the mixed finite element method is higher than the penalty finile element method.An iterative solution method is suggested to solve the system of equations whose coefficient matrices are non positive definite.It is concluded from patch test that the order of interpolation function for pressure variables must be higher than that of displacement variables of solid phase. 相似文献
2.
In this article, modal analysis technology about dynamic analysis was studied. Free interface model comprehensive method was used to dynamic analysis and design of automobile structure based on theory background of model analysis, test technology conditions, data reliability and precision. In order to test the efficient and possibility of the method, main vibration features about space double layer has been calculated based on this method, comparing this with the precise solution of finite element method, the result shows that this method is suitable not only for simple interfaces between components but also for high reductive interfaces. In addition, the method also has high comprehensive precision. Furthermore it creates conditions to dynamic analysis in automobile structures. 相似文献
3.
Considering the relationships of coupling movement and compatible displacement among bonding layer, piezoelectric layer, damping layer, and base structure, a finite element dynamic model of coupled systems for vibration reduction plates is established. The model combined with piezoelectric theory, finite element theory and ADF model of viscoelastic damping material can be suitable for vibration model of complex SCLD structure. The dynamics parameters for clamped-clamped steel plate with partially treated smart constrained layer damping are obtained by theoretical calculation, ANSYS modal analysis and modal experiment. The results show that theoretical values are closer to the test results and ANSYS analysis, and the methods proposed is more accurate and effective. 相似文献
4.
Research for applying the technique of dynamic condensation on the mechanical structure dynamic analysis.The tolerance of the mechanical structure dynamic characteristics has been investigated when it is solved with the useful method of mode condensation.The practice shows that computational result of the dynamic characteristics relating to reserved number of mode and the magnitude of the damping,when the freedom of the complicated mechanical structure finite element model be reduced in big amplitude with the mode condensation technique. 相似文献
5.
QIU Li qiong 《保鲜与加工》2002,(5):148-151
In the process of oil drilling, drilling string and rock bit are main drilling tools. The fact of their failure would cause serious accidents. To solve this problem, the vibration law of string should be found. The longitudinal vibration model, torsional model and lateral vibration model are founded simultaneity. Many methods are used to build up this model, including finite element technique, numerical technique and computer simulation. The dynamic model reveals the dynamic action of string, it is instructive to design new rock bit and study drilling mechanics. 相似文献
6.
分析内嵌管式辐射地板的频域热特性,便于进一步了解内嵌管式辐射地板的动态热特征,为辐射地板的系统和控制设计提供重要的参考依据。建立了内嵌管式辐射地板的频域有限元模型,同时采用ANSYS软件建立了内嵌管式辐射地板的时域传热模型,通过2个模型的对比说明了频域有限元模型的准确性。采用频域有限元模型计算并分析了内嵌管式辐射地板的频域热特性。结果表明,在低频区域,地板的频域热响应基本不随频率变化,其传热过程接近于稳态,而在高频区域,地板的频域热响应随频率的变化十分剧烈,地板传热呈现明显的动态特征。当房间内存在较多成分的高频热扰时,关于辐射地板的传热计算应采用动态计算方法。 相似文献
7.
The behavior of soft tissues of human musculoskeletal system can be describedwith the biphasic model based on a continuum theory of mktures. This paper. using Galerkin weight-ed residual method.obtains a mixed finite element formulation for the linear biphasic model of smalldeformation. and. in turn. gives out the iterative scheme solving the system equations. The results ofnumerical analysis for the constrained compression problem are consistent with those obtained bytheory. which illustrates the correctnas and feasibility of the derived mixed finite element formula-tion. concludingly. this formulation provides an effective means of numerical analysis for the motfonmechanism of human articulating joints. 相似文献
8.
In order to improve the node localization precision of Range Free based DV Hop localization algorithm in wireless sensor networks (WSNs) with randomly distributed nodes and dynamic topology, the improved algorithm is proposed. After analyzing the DV Hop algorithm, considering the obvious errors of the estimated node coordinates calculated by Polygon based method in traditional DV Hop algorithm, the numerical iterative algorithm is constructed by employing Taylor series expansion, and simulation studies for the improved DV Hop algorithm are conducted. The selection criteria for the convergent threshold of iterative step is determined, the localization performance of the improved localization algorithm is analyzed by comparing with the traditional DV Hop algorithm under the same condition of selected convergent threshold and simulation parameters, while the calculation amount and convergence rate of the improved algorithm are also measured by the statistic iterations. The simulation results show that by selecting reasonable iterative threshold values and appropriately increasing calculation amount for node localization, the improved DV Hop localization algorithm greatly improves the localization precision and the error stability, which is feasible for node localization in WSNs with both randomly distributed nodes and dynamic topology. 相似文献
9.
Karst region is a kind of complicated groundsill.To design tall-buildings built on karst subgrade,precise analyse result is needed.The method based on superstruct-foundation-soil interaction theory can precisely calculate the(internal) force of structural,foundation and groundsill.The method of finite element is an effective way to solve the problem.Finite element analys is software ANSYS is used to analyze superstruct-foundation-soil interaction on Karst Subgrade.Through comparing methods based on superstruct-foundation-soil interaction with traditional analysis method(in this condition,superstruct-foundation-soil interaction is not taken into account),the interactional effect to structure,foundation and rock are discussed.Through the analysis,several conclusion can be drawn as follows: The side stress of column is small for buildings on Karst region,but the side stress of corner columns is much larger than the others.The side stress of shear wall is great and the location of shear wall is significant for the interaction.Slab foundation is effective for Karst region,it plays a great role on interaction. 相似文献
10.
The sky luminance distribution model is developed by information analysis methods with ant colony system. A new arithmetic is given to solve complex optimization heuristic algorithm. The coefficient values of sky luminance distribution function are obtained by optimization analysis with ant colony system and on which a set of practical software is developed. It can provide an intuitive and easy calculation. The model has higher precision, which can provide valuable results on high precision and standard daylighting design. 相似文献
11.
The finite element or finite difference method and the limit equilibrium method, with their respective merits, were used to analyze soil slope stability in detail. On the basis of the slice and gravity increase methods, a fundamental principle of couple analysis, and a procedure for calculating the slope safety factor were put forward. ANSYS finite element software and finite difference software FLAC were used to determine the most dangerous sliding face and the stress-stain in slopes. The slope safety factor was determined using the slices limit equilibrium method. The calculation shows that the result obtained using couple analysis is close to the results produced using other methods in the example, and the analysis of the effects of the intensity indices is more precise. The results can provide a basis for consolidating design of the sliding slope. 相似文献
12.
Sensitivity analysis of motorcycle frames is useful for improving the design success rate. Based on sensitivity analysis theory and using the Monte Carlo and numerical simulation methods, a new 250 type integral motorcycle model was built and dynamic sensitivity analysis conducted. Sensitive design parameters that have great influence on frame vibration were discovered. By modifying the values of sensitive design parameters, the vibration of some measuring points was reduced. This reduction shows that the sensitivity analysis method is reliable and practical, and it can be used in sensitivity analyses of other complicated structures. 相似文献
13.
There are obvious geometric nonlinear mechanical characteristics in new type arch bridge with diagonal web cables. Meanwhile, the convergence of the existing arch axis iterative optimization method is not good. In order to solve new type arch bridge axis iteration convergence problem considering geometric nonlinear mechanical analysis, an arch axis iteration optimization method was proposed based on the iteration basis finite element model with two hinge arch model in main arch ring. A 600m span arch bridge with diagonal web cables was selected as an example to test the convergence performance and applicability of proposed method. The results showed that the bending moment of proposed method had better distribution along arch span, and it is about 35% smaller in maximum bending moment, 17% smaller in minimum bending moment and 23% smaller in bending strain energy compared to the results of linear iteration optimization method. Convergence analysis results demonstrated that proposed method had better iteration performance than the existing method. Meanwhile, different initial arch axis can converge to stable results. 相似文献
14.
In this paper according to different cooling feafures in the secondary coolingzone,a two-dimensional mathematic model of heat transfer is developed,which is suitable for the op-eration of the casfer in Chongqin g Special Steel Plant,In the model, a finite difference method isadopted and different boundary conditions a different time-step is firstly used.Thus the model isof high precision with a shorter calculation time.The optimum secondary cooling system of the con-tinuous billet can be gained by aimulating and optimizing calculations using the model. 相似文献
15.
Using regression analysis method,the methods for solving the weights of combination forecasting model(CFM) are proposed. At first, the linear regress CFM are presented based on the least absolute criteria and least square criteria. Then the weights can be evaluated using the least square princinple. Because the objective function of CFM based on least absolute criteria is non differential, the traditional programming methods can not solve it. So the least square method with the modified weights is proposed to solve this problem. At the same time, methods for solving CFM is given with the aim of minimizing sum of percentage error absolutes. From many cases, the results show that the forecasting precision of CFM is very high and the effect of regression is remarkable. 相似文献
16.
To accurately analyze the loss and heat of large hydro generator,the finite element models of 2D steady state electromagnetic field,moving electromagnetic field and field circuit coupling are established respectively.As an example,the losses of the rotor iron and damper winding of a 36 MW tubular hydro generator are calculated.Furthermore,the influences of 3 different electromagnetic field models on the thermal sources and temperatures are analyzed by 3D finite element calculation of the temperature field.The results are compared with the test data and indicate that the precision of the field circuit coupling model is better.The losses of each damp bar are different and the heat of the damp bar at the lee side is larger than that at the windward with the full load.The maximal temperature of the rotor is located at the damper winding,instead of the field winding.The research is valuable for improving the calculation precision of the rotor losses and temperature field and enhancing the reliability of the hydro generator design and operation. 相似文献
17.
Deformation measurement and analysis play an important role in geotechnical model tests. Using the concept of quadrilateral isoperimetric element, the strain filed was achieved from the calculation method based on displacement modes, and the verification results show that this measurement technique has a reliable precision. The soil deformation in model test of square shallow foundation was measured by using this technique, and the results show that the measurement system based on digital image correlation method can realize the whole process quantitative measurement of soil displacement field and shear strain filed. This deformation measurement technique provides a tool for the qualitative and quantitative analysis of soil micromechanics characteristics. 相似文献
18.
Wind turbines operate in harsh environment with transient and variable working conditions. As a result, wind turbines are complicated, nonlinear, uncertain systems. Modeling and analysis of these systems are crucial to their design. Based on MATLAB, a new dynamic simulation model of a stalled wind turbine was presented. The blade element momentum theory and the state space method were programmed into MATLAB/SIMULINK to calculate wind turbine aerodynamic performance. The generator was also modeled in MATLAB/SIMULINK, taking the coupling between the generator and the rotor speed into consideration. Based on the proposed MATLAB model, an analysis of a 600 kW wind turbine was carried out. The calculation values were compared with the measured data. The results indicate the correctness of the proposed MATLAB model. The simulation model can be applied to optimize design and control of stalled wind turbines. 相似文献
19.
The Non-Linear Finite Element Analysis of Cable Structures Based on Four-Node Isoparametric Curved Element 总被引：1，自引：0，他引：1
In this paper,based on the geometric nonlinear behavior of cable structures,a finite element method with four-node isoparametric element was presented,the third order polynomial was used as displacement functions and initial curve of the element.By means of the principle of virtual work and the updated Lagrangian method,the authors derived the finite element equations,and solved them by Newton-Raphson method.The proposed model leads to high precision and can meet the engineering requirements.The model presented in this paper can be applied in the analysis of long-span tension structures,such as cable structures,cable domes and so forth. 相似文献
20.
Because the factors that affect the behavior of the beam-column joints are complicated,an experimental study alone is not sufficient.Therefore,a nonlinear finite element analysis was conducted to provide better understanding of the performance of the beam-column joints.The authors intend to do the parameter study with nonlinear finite element method after a lot of high-strength concrete beam-column joints have been experimented.In this paper,the analytical model firstly was applied to simulate the experimental joint behavior and the comparison results were very well.Based on this,the parametric analysis of concrete strength on seismic performance of beam-column joints has been conducted. 相似文献