Mises Stress Distribution Research Articles

Analysis of expansion performance and parameter sensitivity of solid expandable tubular with thread joint

During the expansion process of the threaded joint of the solid expandable tubular (SET), the thread meshing performance and sealing performance will deteriorate, which seriously hinders the development and application of the SET. In this paper, established the force analysis model of different threads in the bulging process and analysis the finite element model of thread. The meshing performance of φ108 mm × 7 mm SET joints made of 20G steel with three types of thread expansion is analyzed. The most suitable parameter range was obtained by optimizing the five thread parameters such as bearing surface angle, guide surface angle, taper, tooth depth and tooth pitch. The results show that the rectangular and trapezoidal threads are deformed seriously during expansion, and the connection of rectangular and trapezoidal threads is easy to cause the seal failure of the SET system; The effects of various thread parameters on the Mises stress and contact pressure distribution were analyzed. It was found that the Mises stress of the first turn of the special skew trapezoidal thread was the highest, and the Mises stress distribution was high at two ends and low at the middle, with the maximum difference of 160 MPa and the contact pressure distribution was high at two ends and low at the middle, with the maximum difference of 200 MPa. The research results provide technical support for obtaining the SET thread with good meshing performance after expansion.

Numerical study of the effect of geometric parameters on compressive mechanical properties of metallic lattice cylinders

In the current research, the numerical simulations were done on 15 cylindrical lattice specimens under compressive stress at a constant strain rate using Abaqus software. The lattice cylinders have different strut thicknesses of 3, 4, and 5 mm, and with the fillets in the radiuses of 0.3, 0.6, 0.9, and 1.2 mm, respectively. The mechanical properties of the AlSi11Cu2 (Fe) aluminum alloy were used. The Mises stress distribution was evaluated to determine the effect of fillet radius on the lattice structure for the strut thickness of 3 mm. Also, the effective strain distribution of the lattice structure was investigated after different stages of deformation. After comparing the simulation results, it was shown that by applying fillets with a radius of 0.3 mm in lattice cylinders, the maximum energy absorption and maximum force can be achieved at the ultimate tensile strength (UTS) point. Also, the optimal strain can be obtained at the UTS point.

A FEA Method for Deformation Characteristics of Circular Cylindrical Shells Compressed by Two Rigid Plates

Circular cylindrical thin shells as one of the most energy absorbing elements are used in various engineering applications. One of the most important applications is compressing shells laterally between two rigid plates. Many researchers have work on this issue, but it is hard to be analyzed by the theoretical methods. In the present paper, a finite element model was developed to resemble the compressive process of circular cylindrical shell by two rigid plates laterally. Then a dynamic simulation was carried out using ANSYS LS-DYNA program. The cross-sectional profile and Mises stress distributions as well as the load–displacement curve was obtained by the FEA process, which can reveal the main deformation characteristics of circular cylindrical shells compressed between two rigid plates.

A two-parameter model for predicting thermal contact resistance between crystal and aluminum alloy based on turning morphology

Thermal contact resistance (TCR) is a key factor in thermal engineering which affects the thermal-structural design of precision instruments. To reveal the influence of turning morphology on the TCR between potassium dihydrogen phosphate (KDP) crystal and aluminum alloy, a novel simplified model considering two parameters of wavelength and slope is proposed. Meanwhile, the TCR of KDP crystal and aluminum alloy are experimentally investigated to validate this two-parameter model, where the effects of different wavelengths and slopes on Mises stress distribution, temperature distribution, heat flux and TCR can be analyzed. By incorporating the theory of plane turning, the TCR can be reduced by controlling the feed rate and cutting thickness under a certain roughness. This research provides a theoretical basis for the thermal-structural design of crystal modules and the turning of aluminum alloy.

Research on Structure Design of The Dual Steel Disc in Brake Based on Rigid-Flexible Coupling Simulation Analysis

A research method is proposed to improve the structure of the dual steel disc in wet multi-disc brake based on virtual prototype simulation analysis. The finite element flexible body model of the dual steel disc was established by CAE software, and the accuracy of the flexible body model was verified by the method of identifying natural frequency by near-field acoustic radiation. Based on the dependable finite element flexible body model, the rigid-flexible coupling virtual prototype model of the wet multi-disc brake was established, and the dynamic simulation analysis of brake during the braking period was processed. According to the results of brake dynamics simulation, the time-frequency characteristics of friction pair contact force and the change characteristics of piston spring force during the braking process are analysed. Based on credible dynamic simulation analysis, the mises stress distribution and deformation changes of the steel disc at critical moments are acquired. Depending on the virtual prototype analysis results, it is powerful to guide the structural design and improvement of the dual disc, and some phenomena and problems which are difficult to find through actual measurement can be researched effectively.

Effect of void nucleation on microstructure and stress state in aluminum alloy tailor-welded blank

The microscopic damage initiation characteristic in welded joint greatly determines the subsequent damage evolution and fracture behavior of aluminum alloy tailor-welded blank (TWB) during plastic forming. In this study, the interactive dependence of void nucleation on microstructure and stress state in the welded joint of a 2219 aluminum alloy TWB was quantitatively explored by in-situ SEM testing. Moreover, a micromechanical model based on actual microstructure was adopted to reveal the underlying mechanisms from the perspective of microscopic heterogeneous deformation. The results showed that three void nucleation mechanisms, including particle-cracking, interface-debonding and matrix-cracking, coexisted in the deformation at different microstructure regions and stress states. The nucleation strain of each mechanism mainly depended on the particle volume fraction, grain size and stress triaxiality. Besides, the proportions of particle-cracking and interface-debonding greatly varied with the grain size and particle volume fraction, and the variation law changed with the stress state. The proportion of matrix-cracking had a weak dependence on the microstructure, while increased with the stress triaxiality decreasing. It made the damage initiation in aluminum alloy welded joint transit from particle-cracking dominance to matrix-cracking dominance with the stress triaxiality decreasing. The micromechanical modeling results suggested that the changes of evolutions and distributions of Mises stress in particle, hydrostatic stress at interface and plastic strain in matrix with microstructure and stress state were responsible for the above effects.

Dynamic Time Analysis of Glass Fiber Reinforced Polymer – Numerical Simulation and Experiment

Composites are known for their significant damping, however, both reinforcement type or layered arrangement influence the response of material: mechanical, thermal, electrical etc. The paper provides the dynamic time analysis of glass fiber reinforced polymer samples of various layups. The mechanical response to dynamic excitation was tested by numerical simulation and experiment. The excitation function was the unit impulse force generating free damped vibrations. Experimental results were evaluated in time domain to obtain damping parameters. For numerical simulation, the commercial software was used to visualize deformed model in individual damping phases, Mises stress distribution in individual laminate layers, and comparison of that for different layups.

Analysis on the behavior of dispersed plate-type fuel based on fluid-solid coupling method

In this study, a three-dimensional bi-directional fluid-solid coupling method FLUENT-ABAQUS-MpCCI was used to analyze the behavior of the fuel plate. ABAQUS was used to simulate the solid domain, including the heat conduction, mechanical behavior and irradiation effects. Several subroutines were developed and validated, including CREEP, UHARD, USDFLD and UEXPAN. FLUENT was used to simulate the fluid domain, including pressure and temperature. FLUENT and ABAQUS were coupled by MpCCI to consider the interaction between fluid domain and solid domain. Many parameters were obtained, including fluid temperature distribution, Mises stress distribution and strain distribution. The influences of the fluid domain, particle volume fraction, creep behavior and burnup were analyzed. The results showed that the zero-dimensional model or one-dimensional model on fluid could not accurately simulate the mechanical behavior of the fuel plate. The results also showed that the creep behavior could reduce the Mises stress on the cladding.

Finite element analysis of optimization on placement of medial fixed-bearing unicompartmental knee arthroplasty

Objective To investigate the influence of displacement of femoral and tibial components on the biomechanics of femoral or tibial bone in coronal view. Methods A series of CT and MRI of the left knee joint of a Han male volunteer was taken and a three-dimensional finite element model of the healthy knee joint was established. The femoral component and the tibial component were designed with varus 6°, varus 3°, 0°, valgus 3°, and valgus 6°, and were combined into 25 three-dimensional finite element model (FEM) of medial unicompartmental knee arthroplasty. A 1 000 N load was applied along the femoral mechanical axis. The von Mises cloud stress distribution was observed. Moreover, the lateral compartment load ratio, the high contact stress of cancellous bone and medial cortical bone below the tibial component, the upper surface of the polyethylene liner, and the femoral cartilage in the lateral compartment was measured. The statistically significant indicators compared with the neutral position (0° varus or valgus of the tibia and the femoral prosthesis, and 5° posterior slope of tibia prosthesis) were identified by scatter plots to find the dense and sparse areas of point items. The optimal position of the femoral component and the tibial component was determined by the number of items with statistical significance in the sparse area. Results When the femoral component was placed at 0° position, there was no significant difference in the high contact stress of cancellous bone below the tibial component in the five groups. When the femoral component was placed at 0° position, the tibial component was 6° varus or 6° valgus and the stress was increased by 9.21±3.38 MPa and 9.08±4.13 MPa (P<0.05), respectively. With the changes of femoral and tibial components from 6° varus to 6° valgus, the high contact stress of the medial cortical bone below the tibia was gradually decreased (P<0.05). When the femoral component was placed at 0°, the tibial component changes from 6° varus to 6° valgus without significant difference in the high contact stress on the upper surface of each group of polyethylene gasket. Compared with the neutral position group, the high contact stress of the 6° varus or 6° valgus group were increased by 2.88±2.53 MPa and 3.47±2.86 MPa, respective ly (P<0.05). The lateral compartment load ratio and the high contact stress of lateral compartment femoral cartilage was gradually decreased (P<0.05), when the femoral and tibial components changed from 6° varus to 6° valgus. The number (2.8%, 1/36) of indicators in the sparse area (the combination of all combinations of femur or tibia from 3° varus to 3° valgus) was less than that (57.8%, 37/64) in the dense area (set of all combinations except sparse area), and the difference was significant (χ2=29.61, P<0.001). Conclusion It is suggested that the position of the femoral component and the tibial component in fixed medial unicompartmental arthroplasty should not exceed 3° varus or valgus in patients with standard lower limb alignment. Key words: Osteoarthritis, knee; Arthroplasty, replacement, knee; Prosthesis fitting; Finite element analysis

Computer Simulation of Surface Cracks Behavior in Anhydrous Chemical Conversion Coatings on Magnesium Alloy

In the conversion coatings, some uniformly distributed micro surface cracks always occur but the surface cracks behavior is rarely studied due to the frequent initiation in the real test conditions. In this work, computer simulation of micro surface cracks behavior and internal stresses generated in the anhydrous chemical conversion coating was carried out using the finite element method with the help of ABAQUS software. The Mises stress distribution, S 11 stress variation, and the stress-time curves were obtained. The results show that the internal stresses generated in the conversion coating increase obviously with increasing time, and the stresses at the center and boundary of coating pieces are bigger than the ones in other areas while the S 11 stresses around the center are bigger than the ones near the boundary. The cracks at the interface of coating pieces develop gradually and are as V-type cracks finally. The width of crack mouth opened is different since the contraction degree of each coating piece is different.

A Numerical Simulation of a Ni-based Bulk Metallic Glass During Compressive Deformation and Fracture

On the basis of compression tests, uni-axial compression deformation and fracture behaviors of NiTiZrAlCuSi bulk metallic glass samples with different dimensions have been studied by numerical simulation approaches. Finite element models for compression simulation have been developed using ABAQUS software. Shear damage models were employed to reproduce the compression deformation and fracture process of the Ni-based amorphous alloys. Mises stress distribution and equivalent plastic strain obtained numerically during compression were analyzed. The simulation results were consistent with those of the compression experiment tests. The smaller of the samples exhibited larger plasticity and higher fracture strength when compared with the bigger one.

Plastic limit loads for pipe bends with circumferential through-wall crack under torsion moment

In this work, finite element (FE) method is used to determine plastic limit load solutions for pipe bends with circumferential through-wall crack under torsion moment. Both extrados and intrados crack are considered regarding of crack location. Based on FE results estimated solutions are proposed for application, and are also compared with corresponding solutions in previous literatures showing that existing solutions are unfit for prediction of torsion load. The weakening factor W decreases with crack length increasing, and the decreasing rate exhibits three typical stages which performs a similar trend to that with bending moment. Finally a detailed analysis for the mechanical behavior of pipe bends has been conducted which provides some evidence to explain the weaken effect caused by the presence of crack. In torsion mode results show that the non-uniform distributed shear stress is performing symmetric to the profile plane and may have a crucial influence on the weakening factor, while in bending mode the distribution in axial stress and circumferential stress is symmetric to the profile plane and has a decisive influence. Therefore crack is pulled open by in-plane bending load while torn open by torsion load. Some evidence also can be obtained from the Mises stress distribution, where similar variation rule will provide another argument to support such description.

Analysis of Nonlinear Dynamic Response of Wind Turbine Blade Under Fluid–Structure Interaction and Turbulence Effect

In this paper, the entity model of a 1.5 MW offshore wind turbine blade was built by Pro/Engineer software. Fluid flow control equations described by arbitrary Lagrange–Euler (ALE) were established, and the theoretical model of geometrically nonlinear vibration characteristics under fluid–structure interaction (FSI) was given. The simulation of offshore turbulent wind speed was achieved by programming in Matlab. The brandish displacement, the Mises stress distribution and nonlinear dynamic response curves were obtained. Furthermore, the influence of turbulence and FSI on blade dynamic characteristics was studied. The results show that the response curves of maximum brandish displacement and maximum Mises stress present the attenuation trends. The region of the maximum displacement and maximum stress and their variations at different blade positions are revealed. It was shown that the contribution of turbulence effect (TE) on displacement and stress is smaller than that of the FSI effect, and its extent of contribution is related to the relative span length. In addition, it was concluded that the simulation considering bidirectional FSI (BFSI) can reflect the vibration characteristics of wind turbine blades more accurately.

Prediction of Chip Morphology and Cutting Force during Prestressed Cutting of TC4

Chip morphology plays a predominant role in determining machinability and tool wear during the machining of titanium alloys. Chip formation process in prestressed cutting of titanium alloy TC4 was numerically explored via the finite element method. Crack initiation during the chip segmentation was realized by using a ductile fracture criterion which based on the strain energy. Effect of prestress on cutting force and chip formation as well as Mises stress distributions were revealed. The results indicate that chips show the similar characteristic of continuous and regular serrated shape, which is not affected by prestress. Initial stress distribution of workpiece was changed by prestress, which correspondingly leads to the alteration of stress distribution in the subsurface layer. The generated cutting force curves share the same average amplitude and analogous rhythm, which correspond to the chip forming process respectively.

The Influence of Void Orientation on Stress and Strain Fields for Nickel-Based Single Crystal Superalloys under Creep Loading

Fracture surface of crept nickel-based single crystal superalloy specimen shows that voids play significant role in creep rupture. In this study, the unit cell model containing two voids was established to study the influence of void orientation on the stress and strain distribution for nickel-based single crystal superalloy under creep loading with the creep constitutive relationship based on the crystal slip theory. Three cases were considered with different angle between the line connecting the centers of two voids and loading axis. The distributions of equivalent Mises stress, maximal resolved shear stress and equivalent creep strain have been given for different creep stages. The results show that the void orientation has remarkable influence on the void growth and the stress and strain distribution during creep.

Finite Element Analysis of Pharmaceutical Tablet Compaction

A finite element simulation of convex tablet compaction was present in this paper with Drucker–Prager Cap model of lactose material. The effects of different compression speed on tablet property were analysis. The results show that the maximum stress appears the top and bottom near the die and the mises stress distribution become more uniform with the speed decreased. The density distribution change little with the variation of compression speed and the maximum density locate the top and bottom near the die rim. The compression speeds have little affected on the powder displacement. The research can contribute to save cost for tablet production test through the simulation analyze the tablet property of compression process.

Numerical Simulation and Analysis on Bending Forming of Hull Plate

Bending process is one of the important methods to form thick hull plate, whose accuracy is directly related to the quality of hull plate forming.In this paper, bending process of thick hull plate is simulated by using finite element software ANSYS, and some simulation results on bending deformation of thick hull plate such as the deformation of meshes in deformation zone, the distributions of the Von Mises stress and effective strain are obtained.

Proposal of failure criterion applicable to finite element analysis results for wall-thinned pipes under bending load

Abstract In this work, a failure criterion applicable to large strain Finite Element Analysis (FEA) results was proposed in order to predict both the fracture mode (collapse or cracking) and the limit bending load of wall-thinned straight pipes. This work was motivated from the recent experimental results of Tsuji and Meshii (2011) ; that is, fracture mode is not always collapse, and the fracture mode affects the limit bending load. The key finding in comparing their test results and a detailed large strain FEA results was that the Mises stress distribution at the limit bending load of a flawed cylinder was similar to that of a flawless cylinder; specifically, in case of collapse, the Mises stress exceeded the true yield stress of a material for the whole “volume” of a cylinder with a nominal wall thickness. Based on this finding, a failure criterion applicable to large strain FEA results of wall-thinned straight pipes under a bending load that can predict both fracture mode and limit bending load was proposed and was named the Domain Collapse Criterion (DCC). DCC predicts the limit bending load as the lower value of either the McFEA, which is the load at which the Mises stress exceeds the true yield strength of a straight pipe for the whole “volume” with a nominal wall thickness (fracture mode: collapse), or the McFEAb, which is the load at which the Mises stress in a section of the flaw ligament exceeds the true tensile stress (fracture mode: cracking). The results showed that the DCC could predict the fracture mode appropriately and the experimental limit bending load fundamentally on the conservative side within a maximum 20% difference regardless of the fracture mode. Another advantage of the DCC is that it uses the true yield and true tensile strength as the critical strength of the material and not the ambiguous flow strength.

1606 弾性接着突き合わせ継ぎ手の強度基準に関する研究(OS16. 表面・薄膜・接合部の力学と信頼性評価(2),オーガナイズドセッション講演)

In this study, butt joint specimens which have various angles of interface edge (notch type:θ=45.70.80 degrees, cylinder type:θ=90 degrees, protrudent type: θ=100,110.135 degrees) are used for the experiments. Stress and strain distributions at the adhesive interface of these specimens under the critical load are obtained by the elastic finite element analysis with MARC. The apparent adhesive strength increases with increasing interfacial edge angle. This is because that stress concentration at the interfacial edge becomes small for a larger edge angle. On the other hand, the apparent adhesive strength decreases with increasing edge angle for the protrudent type specimen which has no stress concentration. This is because the protrudent area of the specimen takes little load. Adhesive strength increases a little with an increase of loading rate. In the obtained analytical data. Mises stress distribution at interfacial edge is found to be the strength criteria for the adhesive joints strength.

Analysis of micro/mesoscale sheet forming process with uniform size dependent material constitutive model

Based on accurate material models, finite element (FE) method becomes a powerful tool in conventional metal forming process design. However, conventional material models cannot describe the material behaviors in micro/mesoscale due to size/scale effects. As a result, most know-how obtained in traditional macroforming is not suitable for the microforming process.In the present study, a uniform size dependent constitutive model, describing the evaluation of the material behaviors from macroscale to microscale, is established by introducing the scale factor. It contains two different terms: size dependent term and size independent term. Moreover, SUS304 sheet specimens are prepared and uniaxial tension experiments are performed to validate the material model.Based on this uniform size dependent constitutive model, numerical simulation models of micro/mesosheet forming process are established to investigate the influence of the size effects. The results show that there is obvious difference in the punch force and Mises stress distribution between the results with consideration of size effects and that without size effects. Therefore, the size effects should be considered in micro/mesoforming process design.