Modal and Thermal Analysis of a Modified Connecting Rod of an Internal Combustion Engine Using Finite Element Method

The connecting rod is one of the most important moving components in an internal combustion engine. The present work determined the possibility of using aluminium alloy 7075 material to design and manufacture a connecting rod for weight optimisation without losing the strength of the connecting rod. It considered modal and thermal analyses to investigate the suitability of the material for connecting rod design. The parameters that were considered under the modal analysis were: total deformation, and natural frequency, while the thermal analysis looked at the temperature distribution, total heat flux and directional heat flux of the four connecting rods made with titanium alloy, grey cast iron, structural steel and aluminium 7075 alloy respectively. The connecting rod was modelled using Autodesk inventor2017 software using the calculated parameters. The steady-state thermal analysis was used to determine the induced heat flux and directional heat flux. The study found that Aluminium 7075 alloy deformed more than the remaining three other materials but has superior qualities in terms of vibrational natural frequency, total heat flux and lightweight compared to structural steel, grey cast iron and titanium alloy.

A New Isogeometric Finite Element Method for Analyzing Structures

High-performance finite element research has always been a major focus of finite element method studies.This article introduces isogeometric analysis into the finite element method and proposes a new isogeometric finite element method.Firstly,the physical field is approximated by uniform B-spline interpolation,while geometry is represented by non-uniform rational B-spline interpolation.By introducing a transformation matrix,elements of types C^(0)and C^(1)are constructed in the isogeometric finite element method.Subsequently,the corresponding calculation formats for one-dimensional bars,beams,and two-dimensional linear elasticity in the isogeometric finite element method are derived through variational principles and parameter mapping.The proposed method combines element construction techniques of the finite element method with geometric construction techniques of isogeometric analysis,eliminating the need for mesh generation and maintaining flexibility in element construction.Two elements with interpolation characteristics are constructed in the method so that boundary conditions and connections between elements can be processed like the finite element method.Finally,the test results of several examples show that:(1)Under the same degree and element node numbers,the constructed elements are almost consistent with the results obtained by traditional finite element method;(2)For bar problems with large local field variations and beam problems with variable cross-sections,high-degree and multi-nodes elements constructed can achieve high computational accuracy with fewer degrees of freedom than finite element method;(3)The computational efficiency of isogeometric finite element method is higher than finite element method under similar degrees of freedom,while as degrees of freedom increase,the computational efficiency between the two is similar.

Cracking analysis of fracture mechanics by the finite element method of lines(FEMOL)

The Finite Element Method of Lines （FEMOL） is a semi-analytic approach and takes a position between FEM and analytic methods. First, FEMOL in Fracture Mechanics is presented in detail. Then, the method is applied to a set of examples such as edge-crack plate, the central-crack plate, the plate with cracks emanating from a hole under tensile or under combination loads of tensile and bending. Their dimensionless stress distribution, the stress intensify factor （SIF） and crack opening displacement （COD） are obtained, and comparison with known solutions by other methods are reported. It is found that a good accuracy is achieved by FEMOL. The method is successfully modified to remarkably increase the accuracy and reduce convergence difficulties. So it is a very useful and new tool in studying fracture mechanics problems.

Mixed finite element and differential quadrature method for free and forced vibration and buckling analysis of rectangular plates

This paper presents a combined application of the finite element method （FEM） and the differential quadrature method （DQM） to vibration and buckling problems of rectangular plates. The proposed scheme combines the geometry flexibility of the FEM and the high accuracy and efficiency of the DQM. The accuracy of the present method is demonstrated by comparing the obtained results with those available in the literature. It is shown that highly accurate results can be obtained by using a small number of finite elements and DQM sample points. The proposed method is suitable for the problems considered due to its simplicity and potential for further development.

STRESS FIELD ANALYSIS OF EXTRA-HEIGHT FORGING DIE USING FINITE ELEMENT METHOD

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Transient analysis of 1D inhomogeneous media by dynamic inhomogeneous finite element method

The dynamic inhomogeneous finite element method is studied for use in the transient analysis of one dimensional inhomogeneous media. The general formula of the inhomogeneous consistent mass matrix is established based on the shape function. In order to research the advantages of this method, it is compared with the general finite element method. A linear bar element is chosen for the discretization tests of material parameters with two fictitious distributions. And, a numerical example is solved to observe the differences in the results between these two methods. Some characteristics of the dynamic inhomogeneous finite element method that demonstrate its advantages are obtained through comparison with the general finite element method. It is found that the method can be used to solve elastic wave motion problems with a large element scale and a large number of iteration steps.

DEFORMATION ANALYSIS OF SHEET METAL SINGLE-POINT INCREMENTAL FORMING BY FINITE ELEMENT METHOD SIMULATION

Single-point incremental forming （SPIF） is an innovational sheet metal forming method without dedicated dies, which belongs to rapid prototyping technology. In generalizing the SPIF of sheet metal, the deformation analysis on forming process becomes an important and useful method for the planning of shell products, the choice of material, the design of the forming process and the planning of the forming tool. Using solid brick elements, the finite element method（FEM） model of truncated pyramid was established. Based on the theory of anisotropy and assumed strain formulation, the SPIF processes with different parameters were simulated. The resulted comparison between the simulations and the experiments shows that the FEM model is feasible and effective. Then, according to the simulated forming process, the deformation pattern of SPIF can be summarized as the combination of plane-stretching deformation and bending deformation. And the study about the process parameters＇ impact on deformation shows that the process parameter of interlayer spacing is a dominant factor on the deformation. Decreasing interlayer spacing, the strain of one step decreases and the formability of blank will be improved. With bigger interlayer spacing, the plastic deformation zone increases and the forming force will be bigger.

B-Spline Wavelet on Interval Finite Element Method for Static and Vibration Analysis of Stiffened Flexible Thin Plate

A new wavelet finite element method(WFEM)is constructed in this paper and two elements for bending and free vibration problems of a stiffened plate are analyzed.By means of generalized potential energy function and virtual work principle,the formulations of the bending and free vibration problems of the stiffened plate are derived separately.Then,the scaling functions of the B-spline wavelet on the interval(BSWI)are introduced to discrete the solving field variables instead of conventional polynomial interpolation.Finally,the corresponding two problems can be resolved following the traditional finite element frame.There are some advantages of the constructed elements in structural analysis.Due to the excellent features of the wavelet,such as multi-scale and localization characteristics,and the excellent numerical approximation property of the BSWI,the precise and efficient analysis can be achieved.Besides,transformation matrix is used to translate the meaningless wavelet coefficients into physical space,thus the resolving process is simplified.In order to verify the superiority of the constructed method in stiffened plate analysis,several numerical examples are given in the end.

Radial Force Analysis of Polydioxanone Coronary Stent by Finite Element Method

Coronary stent is used to treat stenosis artery by recovering the luminal diameter of artery and maintaining the normal blood flow. The geometry of coronary stent is an important factor for the radial force. In this study,the relation between the radial force of stent and crown angle was discussed. The result showed that there was no particular rule between the radial force of stent and the crown angle. The maximum radial force of stent was obtained when the crown angle was 50. 04° and the minimum radial force was got when the crown angle was 75°.

Development of Finite Element Limiting Analysis Method and Its Applications in Geotechnical Engineering

The Finite Element Limiting Analysis Method(LELAM) has the advantage of combining a numerical analysis method with traditional limiting equilibrium methods.It is particularly applicable to the analysis and design of geotechnical engineering.In the early 20th century,FELAM has been developed vigorously in domestic geotechnical engineering over international common finite element procedures.It has made great achievements in basic theory research and computational precision,thus broadening the application fields in practical projects.In order to gradually make innovations in geotechnical design methods,some of our research results are presented,mainly including geotechnical safety factor definitions,the principles for use of the method concerned,the overall failure criterion,the deduction and selection of the yield criterion,and the measurement to improve the computational precision,etc..The application field has been broadened from two-dimensional to three-dimensional,from soil slope to jointed rock slope and foundation,from stable seepage to non-stable seepage,from slope and foundation to tunnel.This method has also been used in search of many hidden sliding surfaces of complex landslides,conducting the structural support design considering the interaction between the soil and the structure,and computing simulation foundation bearing plates load tests,etc..

Full－range nonlinear analysis of fatigue behaviors of reinforced concrete structures by finite element method

The offshore reinforced concrete structures are always subject to cyclic load, such as wave load.In this paper a new finite element analysis model is developed to analyze the stress and strain state of reinforced concrete structures including offshore concrete structures, subject to any number of the cyclic load. On the basis of the anal ysis of the experimental data,this model simplifies the number of cycles-total cyclic strain curve of concrete as three straight line segments,and it is assumed that the stress-strain curves of different cycles in each segment are the same, thus the elastoplastic analysis is only needed for the first cycle of each segment, and the stress or strain corresponding to any number of cycles can be obtained by superposition of stress or strain obtained by the above e lastoplastic analysis based on the cyclic numbers in each segment.This model spends less computer time,and can obtain the stress and strain states of the structures after any number of cycles.The endochronic-damage and ideal offshore concrete platform subject to cyclic loading are experimented and analyzed by the finite element method based on the model proposed in this paper. The results between the experiment and the finite element analysis are in good agreement,which demonstrates the validity and accuracy of the proposed model.

Modeling Technology in Finite Element Analysis of Electrostatic Proximity Fuze Problem

In order to analyze the electrostatic field concerned with electrostatic proximity fuze problem using the available finite analysis software package, the technology to model the problem with a scale reduction object and boundary was presented. The boundary is determined by the maximum distance the sensor can detect. The object model is obtained by multiplying the terms in Poisson's equation with a scale reduction factor and the real value can be reconstructed with the same reverse process after software calculation. Using the finite element analysis program, the simulation value is close to the theoretical value with a little error. The boundary determination and scale reduction method is suitable to modeling the irregular electrostatic field around air targets, such as airplane, missile and so on, which is based on commonly used personal computer (PC). The technology reduces the calculation and storage cost greatly.

NONLINEAR ANALYSIS OF REINFORCED CONCRETE RECTANGULAR SLABS USING FINITE ELEMENT METHOD

The nonlinear analysis of reinforced concrete rectangular slabs undermonotonic transverse loads is performed by finite element method.The layered rectangu-lar element with 4 nodes and 20 degrees of freedom is developed,in whichbending-stretching coupling effect is taken into account.An orthotropic equivalentuniaxial stress-strain constitutive model of concrete is used.A program is worked out andused to calculate two reinforced concrete slabs.The results of calculation are in goodconformity with the corresponding test results.In addition,the influence of tension stif-fening effect of cracked concrete on the results of calculation is discussed.

ALE FINITE ELEMENT ANALYSIS OF NONLINEAR SLOSHING PROBLEMS BASED ON F LUID VELOCITY POTENTIAL

Base d on fluid velocity potential, an ALE finite element formulation for the analysi s of nonlinear sloshing problems has been developed. The ALE kinemat ical description is introduced to move the computational mesh independently of f luid motion, and the container fixed noninertial coordinate system is employed to establish the governing equations so that the mesh is needed to be updated in this coordinate system only. This leads to a very simple mesh moving algorithm which makes it easy to trace the motion of the moving boundaries and the free su rface without producing undesirable distortion of the computational mesh. The fi nite element method and finite difference method are used spacewise and timewise , respectively. A numerical example involving either forced horizontal oscillati on or forced pitching oscillation of the fluid filled container is presented to illustrate the effectiveness and the robustness of the method. In additi on, this work can be extended for the fluid structure interaction problems.

Parametric Analysis of Tensile Properties of Bimodal Al Alloys by Finite Element Method

An axisymmetrical unit cell model was used to represent a bimodal Al alloy that was composed of both nano-grained （NG） and coarse-grained （CG） aluminum. Effects of microstructural and materials parameters on tensile properties of bimodal AI alloy were investigated by finite element method （FEM）. The parameters analyzed included aspect ratios of CG Al and the unit cell, volume fraction of CG Al （VFCG）, and yield strength and strain hardening exponent of CG Al. Aspect ratios of CG Al and the unit cell have no significant influence on tensile stress-strain response of the bimodal Al alloy. This phenomenon derives from the similarity in elastic modulus and coefficient of thermal expansion between CG AI and NG Al. Conversely, tensile properties of bimodal Al alloy are extremely sensitive to VFCG, yield strength and strain hardening exponent of CG Al. Specifically, as VFCG increases, both yield strength and ultimate tensile strength （UTS） of the bimodal Al alloy decreases, while uniform strain of bimodal AI alloy increases. In addition, an increase in yield strength of CG Al results in an increase in both yield stress and UTS of bimodal AI alloy and a decrease in uniform strain of bimodal Al alloy. The lower capability in lowering the increase of stress concentration in NG Al due to a higher yield strength of CG Al causes the lower uniform strain of the bimodal AI alloy. When strain hardening exponent of CG Al increases, 0.2% yield stress, UTS, and uniform strain of the bimodal Al alloy increases. This can be attributed to the increased work-hardening ability of CG Al with a higher strain hardening exponent.

Goal-oriented error estimation applied to direct solution of steady-state analysis with frequency-domain finite element method

Based on the concept of the constitutive relation error along with the residuals of both the origin and the dual problems, a goal-oriented error estimation method with extended degrees of freedom is developed. It leads to the high quality locM error bounds in the problem of the direct-solution steady-state dynamic analysis with a frequency-domain finite element, which involves the enrichments with plural variable basis functions. The solution of the steady-state dynamic procedure calculates the harmonic response directly in terms of the physical degrees of freedom in the model, which uses the mass, damping, and stiffness matrices of the system. A three-dimensional finite element example is carried out to illustrate the computational procedures.

Dynamic Analysis of a Centrifugal Compressor by Finite Element Method

This paper mainly deals with dynamic analysis of rotor-bearing system in a centrifugal compressor. A finite element model of the rotor-bearing system has been developed. The considered factors of the model include the rotary inertia of solid elements, stiffness and damping of hydrodynamic bearing. In the calculating, ANSYS software was used. Both calculated and measured results are in good agreement.

Static Analysis of Eolic Blade through Finite Element Method and OOP C＋＋

This work deals with a description of an elastic analysis of eolic blade （preprocessing, processing and post-processing stages）. The eolic blade geometry is approximated by flat finite elements in which the membrane effects are evaluated using the FF （free formulation） finite element and the flexure effects are calculated using DKT （discrete shear triangle） finite element. The pre-processing stage is implemented using OpenGL library, to provide the graphical construction for geometry, mesh orientation, and other requirements of the finite element model. For the processing stage is built a specific dll （dynamic link library） library implemented in C＋＋ language for the FF and DKT elements analysis. The post-processing stage has been built using specific dialogs to present all results in the graphic interface, where the static displacements of the eolic blade model are shown.

Elasto-Plastic Analysis of Tubular Joints of Offshore Platforms by Finite Element Method

The plastic node method is reformulated by the variational principle and is applied to elasto-plastic finite element analysis of tubular joints, eventually including the effect of internal and external gussets, stiffener rings, etc., if necessary. Four different joints are studied here in detail for the elasto-plastic behavior, the strain at the hot spot, the strain concentration factor around the intersection line, and the propagation of the plastic region with loading up to collapse in order to determine the ultimate strength, safety factor, and development of the plastic field. The present results are in good agreement with the experimental results.

VARIATIONAL PRINCIPLES OF PERFORATED THIN PLATES AND FINITE ELEMENT METHOD FOR BUCKLING AND POST-BUCKLING ANALYSIS

On the basis of the general theory of perforated thin plates under large deflections, variational principles with deflection w and stress function F as variables are stated in detail.Based on these princi- ples,finite element method is established for analysing the buckling and post-buckling of perforated thin plates. It is found that the property of element is very complicated,owing to the multiple connexity of the region.