Maximum Equivalent Stress Value Research Articles

Finite element optimization analysis of minimally invasive screw treatment for Sanders typeⅡcalcaneal fracture

To explore biomechanical characteristics of minimally invasive different screw fixations in treating Sanders typeⅡcalcaneal fractures. Dicom data of calcaneus by CT scan were input into Mimics 21.0 software and Ansys15.0 software to construct three-dimensional finite element digital model of calcaneus;this model was input into UG NX 10.0 software, and calcaneus was cut according to Sanders classification to establish Sanders typeⅡ calcaneus model with posterior articular surface collapse;then simulated minimally invasive screw internal fixation after calcaneal fracture:a screw from posterior articular surface was used to outside-in fix sustentaculum tali, other 4 screws were used to fix calcaneus by different methods through calcaneal tuberosity, and 4 different calcaneal models were obtained. Under the same conditions, 4 types of internal fixation models were loaded respectively, and nonlinear finite element analysis was performed to calculate the stress distribution of different internal fixation models. Under the same condition of loading, the model 3 had smaller displacement value, maximum calcaneus displacement value and maximum equivalent stress value of the screw than other three internal fixation models, and the stress was more dispersed. In minimally invasive screw internal fixation of calcaneus fracture, after 1 sustentaculum tali screw fixation, 2 screws crossed fix posterior articular surface from calcaneal tuberosity, 2 screws fix parallelly calcaneocuboid joint from calcaneal tuberosity are more suitable for biomechanical requirements, and could provide basic theory for clinical treatment.

Designing, modeling, and structural analysis of a newly designed double lobe camshaft for a two-stroke compressed air engine

With the rapid increase of urbanization and industrialization, the energy demand has expeditiously risen. The natural resources are limited and will be extinct in the next few years. If the depletion of fossil fuels continues at the same rate as it is, the world will suffer from severe energy scarcity in the nearer future. Therefore, to reduce the dependency on liquid-based petroleum fuels, there is an urgent need for alternative fuels that could compensate for diesel demand and reduce harmful emissions from the atmosphere. The paper presents the designing, modeling, and analyzing a newly designed double lobe camshaft for a compressed air engine. In this study, a 100-cc Four-Stroke SI engine manufactured by Bajaj Auto, an Indian motorcycle manufacturer, was used and tested on compressed air. The engine was modified from a conventional four-stroke to a two-stroke engine by designing a new camshaft for opening the valves at different timings. The newly designed camshaft contains axisymmetric double lobes on both the inlet and outlet cams. Thus, in one complete revolution of the crankshaft, both the valves open once, resulting in one power stroke and one exhaust stroke, eliminating the compression and intake stroke. Any modifications in the camshaft cause various changes in the stress distribution and deformation along the shaft, which should be studied to provide us vital information about the life and effectiveness of the new modified camshaft. The objective is to determine the new valve lift profile, deformation, and equivalent (Von-Mises) stress under loading conditions on the double lobe camshaft. The designing and modeling of the camshaft are done in SOLIDWORKS 2020, and structural analysis is carried out in ANSYS 2020. The maximum total deformation resulted from the analysis comes out to be 5.72 × 10-4 mm, and the maximum value of equivalent stress evaluated is 31.17 MPa.

Computation of Stress Distribution in Hydraulic Horizontal Propeller Turbine Runner Based on Fluid–Structure Interaction Analysis

In the hydro-turbine operation, the kinetic energy of flowing fluid is converted into mechanical energy. In the turbine operation, fluid induces hydraulic load that not only provides a useful mechanical driving torque on the turbine shaft but also causes deformation in turbine components and stress distribution that might induce a structure failure. Structural failure in turbine component decreases performance as well as increases the maintenance cost of hydro-turbines. In this paper, fluid–structure interaction model is used to investigate the stress distribution and total deformation of hydraulic horizontal propeller turbine runner (HHPTR) with different flow velocities, blade widths and blade wrap angles. The results showed that the effects of blade wrap angles and blade width significantly influence the performance and structural strength of the HHPTR. Maximum turbine performance was observed at blade wrap angle of 100° and blade width of 2 mm. It was also found that the maximum value of equivalent stress near the runner hub is 59.54 MPa at blade wrap angle 100°. Similarly, the maximum value of total deformation in HHPTR is 0.7689 mm near the runner blade edges at blade wrap angle 60°.

Biomechanical Analysis of Orthopedic Screw Under Bone Remodeling

In order to evaluate the biomechanical stability of titanium alloy screw with different structural parameters under bone remodeling, some three-dimensional finite element models were established and the bone remodeling process after implanting the screw was simulated. Three-dimensional finite element models consist of bone and screw with different lengths and diameters. Bone remodeling process was simulated by user-defined subroutine. It is found that the stress on the bone is concentrated on the groove and root of the internal thread. The screw stress is mainly on the beginning of the thread, and the whole stress decreases along the long axis of the screw. The stress distribution trend of bone and screw did not change significantly during the bone remodeling. The maximum equivalent stress value was different, the maximum equivalent stress on the screw and cancellous bone increased while the maximum equivalent stress value on the cortical bone decreased.

Simulation and Optimization Design of CRH380A EMU Bogie Frame

Taking SKMB-200 power bogie frame applied to CRH380A EMU as the research object, based on UIC615-4 standard, four kinds of simulated operating conditions load and one kind of supernormal load are calculated, and then constraints and loads required for ABAQUS simulation analysis are determined. The results of static strength simulation show that the maximum stress of the frame under simulated operation conditions, and under abnormal load conditions are lower than the allowable stress of the main material SMA490BW weathering steel. The static strength of the frame meets the standard. Then, through setting design variables, selecting constraints and determining the objective function, the structural optimization analysis of the selected abnormal load cases is carried out. The optimization results show that the total mass is reduced by 109 kg, which is 6.8% lower than that before optimization, and the maximum equivalent stress value of the frame is 329.98 MPa, which still meets the strength requirements. By optimizing the structural parameters of the frame, the under-spring mass of SKMB-200 bogie can be effectively reduced, and its dynamic performance can be improved, which can provide reference for the optimum design of the bogie structure of EMU.

Optimized Design for a Combined Die with Two Stress Rings in Cold Forging Considering Thermal-Mechanical Effects

Stress analysis and optimization of combined die structure with two stress rings were performed. Using thermoelastic deformation, the contact pressure at the interfaces between layers was calculated. Then, theoretical expressions of stress distribution for the combined die were derived. The thermal-mechanical effect under working conditions was considered. To verify the theoretical expressions, simulation work was performed. Optimization of die design was carried out by defining radius ratio and shrink fit coefficient as optimization variables. The objective was to minimize the effective circumferential stress at the inner surface of the die insert, under the constraint that the maximum equivalent stress values of die insert and stress rings did not exceed their respective yield stresses. The Kriging model was used to describe the influence of shrink fit and die dimensions on the objective function and the maximum equivalent stress. Using a genetic algorithm, optimum parameters were found with a minimum circumferential stress of 442.9MPa under a working stress of 1 800MPa. Further analysis of five selected optimal results was carried out, and the specific design parameters of these combined dies are different under the same level of circumferential stress, and the combined die is overdesigned if the thermal effect is ignored.

Conceptual design and finite element analysis of a high inclusion dough shaping machine using 3D‐computer aided design (CAD) (SolidWorks)

AbstractDue to unavailability of omit suitable machine to shape oat base cookies dough with large inclusion, inconsistency in size is a critical issue. Thus, a dough shaping machine is needed to improve the quality of the final product. The objectives of this research are to develop conceptual designs of a high inclusion dough shaping machine and to perform finite element analysis on the important part of the machine. The methodology including extraction of the design layout of the machine, development of the schematic drawing and wireframe model, the performance of stress and total deformation, and production of a complete drawing for fabrication purpose. Under finite element analysis, result of the maximum allowable stress was compared with the calculated static component strength against crack. Based on the analysis using SolidWorks, the maximum equivalent stress of the roller is 0.3469 MPa with maximum total deformation is 2.617 ⋅ 10−4 mm. The value of maximum equivalent stress is way too small as compared to that of the calculated static component strength against crack which is 15.31 MPa. Hence, the material used for the roller was found to be able to support the weight of dough without crack and avoid critical deformation during the production process.

Analysis of Pressure Fluctuation and Stress Deformation in Reverse Generation of Large Vertical Axial Flow Pump

In order to study the stability of the reverse generation of a pumping station in the eastern route of the South to North Water Transfer Project, a full numerical simulation of the flow passage was carried out to study the pressure fluctuation and the stress distribution law in the reverse generating condition. At the inlet of the guide blade, the monitoring points are set up in three sections of the inlet and outlet of the runner. The calculation results show that the pressure pulsation at the outlet of the wheel is the largest, the pressure pulsation between the guide vane and the wheel is the second, and the pressure pulsation at the inlet of the guide blade is the smallest. At the inlet and outlet of the impeller, the blade is dominated by the frequency. The flow state is uneven, and the pressure fluctuating from the hub to the rim gradually increases. The results of fluid solid coupling show that the stress mainly concentrates on the blade pressure surface and the root of the suction surface, and the maximum equivalent stress appears at the impeller root of the suction surface of the blade. The maximum equivalent stress value is in the safety range of the blade material, and does not affect the life and failure of the turbine running unit.

Dynamic Analysis of Shaft Structure Based on ANSYS/LS-DYNA

In this study, a part of the shafting structure of the accessory transmission system consisting of shaft-gear-bearing is studied. ANSYS/LS-DYNA explicit dynamics simulation software is used to simulate the dynamics of the shaft structure. It compares and analyzes the overall shaft structure, gears and bearings. The simulation results show that: The place where the equivalent stress of the shaft structure is relatively large is mainly concentrated at the tooth root and the tooth surface, where the stress is mainly in the vicinity of two or three teeth. With the change of time, the maximum equivalent stress value and position of the rolling elements are also correspondingly changed, it provides a reference for the design and optimization of gear and bearing in the actual assembly process for transmission system.

Explicit dynamics simulation of Pecan fruit deformation under compressive loading-Part-2: Explicit dynamics simulation procedure

This study, which is divided into two parts, introduces an explicit dynamics simulation procedure for Pecan fruit (Carya illinoinensis) deformation under compressive loading. This second part of the study covers a microstructure investigation for the inner structure of the Pecan fruit components, discussions on the material models used in FEM-based simulation, and the explicit dynamics simulation procedures. An application algorithm based on experimental and theoretical methods is described in the study. Visual understanding and/or presenting a detailed description of the deformation behavior/characteristics for agricultural products through analytical calculations or/and physical experiments is a complicated phenomenon. Most especially, this phenomenon becomes more complicated for shelled edible agricultural products under varying loading cases. Numerical method based advanced engineering simulation techniques may be useful for a deeper visual understanding of agricultural product deformation behavior/characteristics. A major focus of the second part of the study detailed in this paper is finite element method (FEM) based explicit dynamics simulation procedures and the realistic representation of time dependant nonlinear deformation of Pecan fruit (kernel-in-shell) under a two plate compression loading case. Simulation results pointed out that the maximum equivalent stress values were 18.10, 11.50, and 1.14 MPa for whole Pecan fruit (kernel-in-shell), the shell and the kernel respectively. The stress values on the kernel were beyond the defined damage point of the kernel material (0.380 MPa). This indicated a permanent deformation/damage on the kernel at the end of the defined compression case. This study contributes to further research into the utilization of nonlinear explicit dynamics based deformation simulation studies for shelled edible agricultural products. Practical applications The simulation approach and application algorithm introduced in this two-part study is a scientific novelty because the explicit dynamics simulation approach for Pecan fruit deformation has not been previously reported in the literature. This second part introduces deeper investigations on material model description, microstructure investigation and FEM-based explicit dynamics simulation procedures. This simulation aims to represent a realistic nonlinear deformation case of the fruit which is very difficult to obtain through experimental and/or mathematical expressions. As a further step from other researchers, this study has introduced a novel realistic time-dependant nonlinear deformation simulation study based on experimental data. The findings have been presented in a form which may be used as input parameters in design studies for shelled agricultural product processing machinery systems used in related industries.

Nonlinear FEM based high-speed shell shattering simulation for shelled edible agricultural products: Pecan fruit shattering

This paper introduces an advanced engineering simulation procedure for the nonlinear finite element method (FEM) based high-speed shattering case of shelled edible agricultural products. A high-speed impactor which is targeted at the Pecan fruit (kernel-in-shell) was considered in this case study. Physical compression tests were conducted on Pecan fruit specimens and experimental deformation characteristics were utilized to describe realistic material models in the FEM based engineering simulation. Subsequently, a reverse engineering approach was employed in the solid modeling stage and the Pecan shell shattering case under high-speed loading was simulated, considering the explicit dynamics approach. The effect of the high loading rate on the deformation characteristics of the Pecan fruit components was observed. Visual outputs from the simulation revealed the shattering behavior of the Pecan fruit components under defined boundary conditions. In addition to useful visual simulation outputs, time-dependant stress distributions on the Pecan fruit under high-speed loading rates were represented using graphs. Simulation results have revealed that maximum equivalent stress values were 7.1 (MPa), 5.1 (MPa), and 0.336 (MPa) for shell, packing material, and kernel, respectively. Maximum reaction force at impact was calculated as 996,000 (N). This work contributes to further research into the use of nonlinear numerical method based high-speed deformation simulation studies for shelled edible agricultural products.

Numerical shape optimization of cold forging tools by means of FEM/BEM simulation

The procedure of a numerical shape optimization of the cold forging tool geometry allows for a reduction and a homogenization of tool load stresses. This procedure considers the workpiece-tool-machine interaction by means of the FEM/BEM coupling. The coupling requires modifications to insure accurate integration in TOSCA software for further shape optimization. The resulting distribution of the nodal displacements and changes of tool geometry are discussed and analyzed. Additionally, the numerical validation of the results by means of mechanical simulation of the optimized geometry with the extended FEM/BEM model is given. The equivalent stresses distribution at the end of lateral extrusion in the tool and in workpiece is presented. The numerical shape optimization leads to the maximum equivalent stress value reduction on the press shoulder on 856 MPa, corresponding to a percentage decrease of 24.3 % in comparison with the initial geometry. The approach for the compensation of load induced workpiece deviations, involving the described optimization procedure, is presented as well.

Vibration characteristics of the impeller at multi-conditions in mixed-flow pump under the action of fluid-structure interaction

In this study, the flow field and impeller structure response in the mixed-flow pump are cooperative solved based on the bidirectional synchronization solving method, to study the vibration characteristics of the mixed-flow pump impeller rotor under the fluid-structure interaction. The pressure distributions of blade surface in the mixed-flow pump under different flow rate conditions were compared, and the deformation, equivalent stress distribution and natural vibration frequency of impeller blade under static force load were studied. Meanwhile, the deformation of impeller blade and coupling stress distribution was analyzed based on bidirectional fluid-structure interaction. The results show that the deformation of impeller blade increases from hub to rim, and the maximum deformation occurs at the rim of the blade. The stress distribution of impeller blade in the circumferential direction is symmetrical, and the maximum equivalent stress occurs at the blade outlet edge near the hub. The maximum deformation position and the stress concentration location are basically consistent before and after coupling calculation, but the maximum deformation value increases and the maximum equivalent stress value decreases under the fluid-structure interaction. The influence of water pressure on the strength and frequency of vibration is very limited. With the increase of flow rate, the maximum equivalent stress of impeller decreases and the total deformation increases gradually. The results of this research provide reference basis for the structure design and reliability analysis of the mixed-flow pump.

Study on plastic deformation behavior of hot splitting spinning of TA15 titanium alloy

The plastic deformation behavior of hot splitting spinning of TA15 titanium alloy is a complex metal forming problem with multi-factor coupling interactive effects. In this paper, on condition of considering various thermal effects, a three-dimensional (3D) elastic–plastic coupled thermo-mechanical finite element (FE) model of hot splitting spinning of TA15 titanium alloy is established using the dynamic, temp-disp, explicit module of FE software ABAQUS. Based on the analysis of flow behaviors of TA15 titanium alloy, the mechanism and influence of materials plastic deformation behavior during the forming process are studied. The results show that, the flow stress of TA15 titanium alloy generally decreases with the increase of deformation temperature; at the same strain rate, the higher temperature is, the lower flow stress is. The temperature distributions along the circumferential direction of disk blank are even and the temperature of plastic deformation area is about 984°C. The heat from plastic deformation and friction at local plastic deformation area is less than the dissipated heat, so the temperature just falls into approximately 945°C. Radial spinning force as the driving force of plastic deformation increases gradually and reaches about 35kN at the end. The maximum value of equivalent stress is presented in fillet part between disk blank and two mandrels. The distributions of equivalent plastic strain appear the large strain gradients and the obvious characteristics of inhomogeneous deformation. When friction factor on interfaces between disk blank and dies ranges from 0.4 to 0.6, the forming quality and precision are highest.

The Optimal Design of Cold Extrusion Die and its Realization

According to the structure optimization of combined extrusion die, using finite element method to establish parametric model and optimize the combination die, compare the results with the result of Lame formula to prove the correctnesss of finite element method; and adjust the structure of concave of die basing the optimal result, so as to reduce the stress concentration and the maximum equivalent stress value on the concave mould, and thus the life-span of the die is prolonged.

Finite Element Analysis of Stamped Tees Stress in Directly Buried Heating Pipeline

In order to provide evidence for optimization design of directly buried heating pipeline tees, finite element models of tees with different ratios of branch-main pipe diameters had been established and simulated by structure analysis soft ANSYS. The change law of maximum equivalent stress values in pipe-nozzle intersection area had been obtained at same temperature, pressure loads and displacement constraints. The results show that maximum equivalent stress values of stamped tees are less than welded tees with same specifications. And stamped tees with lager fillet radius and local wall thickness can effectively decrease maximum equivalent stress values of pipe-nozzle intersection area.

Stress Analysis of Perforated Plate Based on ANSYS

Based on nonlinear FEA software ANSYS, 3D simulation models of eighteen-type perforated plate that have different open-pore number was established. Analysis results indicate: Maximum equivalent stress of perforated plate mainly takes place on symmetry center of outer open-pore for open-pore area. With increasing open-pore number, maximum equivalent stress and each-direction maximum stress of perforated plate presents to enlarge trend. When open-pore number less than or equal to twelve, value of maximum equivalent stress mainly is decided by Z-direction maximum stress. When open-pore number greater than twelve, value of maximum equivalent stress mainly is decided by Y-direction maximum stress. When ratio m less than 2, with increasing ratio m, maximum equivalent stress and each-direction maximum stress of perforated plate presents to reduce trend. When X-direction and Y-direction open-pore numbe of perforated plate is basically equilibrium distribution, X -direction maximum stress is about equle to half of maximum equivalent stress.

Failure Analysis and Structure Improvement of Beam of Liner Vibrating Screen

Aiming at the frequently fracture happening in the large-scale liner vibrating screen beams, the software of finite-element analysis, ANSYS is used to analyze the modal and harmonic response of the beam structure. The analysis result suggests the danger area where beam is prone to fracture because of fatigue. The improvement scheme of the beam structure is proposed and a theoretical basis is provided for the same type of product design in the future. The failure form of the beam is fatigue failure. The maximum equivalent stress value of the improved beam structure comparing to the original design is decreased obviously, improving the stress state and the fatigue life and reliability of the liner vibrating screen.

A Three-Dimensional Atomic-Scale Finite Element Model for a Copper Nano Thin Film Subject to a Uniaxial Tension

A three-dimensional atomic-scale finite element model was developed in this paper for simulation of a nano-scale uniaxial tension. First, the Morse’s potential function was used to simulate the forces acting among particles. Furthermore, a non-linear spring and dashpot element with a lumped mass was used to establish an atomic model. The elongation of the spring at fracture was used to simulate the radius of fracture of the atomic link. This method was applied to investigate the proportional tension test of an idealized FCC single crystal copper film along the x direction. The study includes the stress-strain curve, the effect of five categories of atomic distances on the stress-strain curve; and the effect of strain-rate on the stress-strain curve. The results showed that (1)the simulated maximum stress for copper is very close to 30.0GPa, which is also the value of maximum equivalent stress obtained by Lin and Hwang [6], verifying the validity of the calculation of this paper. In the tension test of copper, necking develops gradually and eventually leads to fracture. The simulated deformed material element during each stage of deformation was similar to that simulated by Komanduri et al.[2](2)the influence of =6.2608 on the five categories of atomic distance considered was limited and it may be neglected to save computation time,(3)when the strain-rate was large, the resistance to deformation was also large, leading to an increase in the yield stress and fracture stress.

Stress Analysis of Tubular Turbine Based on Fluid-Structure Coupling

A brief introduction of fluid-structure coupling and its classification were given, then according to the solving characteristics and application conditions of different coupling methods; sequential coupling method is chosen to calculate the stress distribution of a tide power plant tubular turbine. Stress calculations of the tubular turbine were conducted under the maximum water head, the designed water head, the average water head and the minimum water head working conditions in ANSYS Workbench. The research shows that in all of the four calculated working conditions, the maximum equivalent stress of the runner is located at the connection between the blades and the hub where stress concentration is obvious; the maximum deformation of the runner lies in the outer edge of the blades and the deformation increases from the root to the outer edge; the maximum equivalent stress of the guide vane is located at the root and the maximum deformation lies in the outer edge. The maximum value of maximum equivalent stress of the runner and the guide vane occurs on the maximum water head working condition, whereas it is far less than the material yield limit, which means that static stress will not lead to the cracks of the blade or the guide vane. But it is still necessary to avoid stress concentration appearing periodically in case it causes fatigue failure.