Von Mises Equivalent Stress Research Articles

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.

Finite element analysis of the CFRP-based 3D printed ankle-foot orthosis

Abstract The application of the 3D printing and additive manufacturing in making medical devices have become widespread in the last decades as the opportunity of the technology is rapidly growing. Notably, the Fused Deposition Modeling (FDM) in 3D printing technique has been applied to develop the ankle-foot orthosis (AFO) with different materials and composites. This paper presents a new design and simulation results of a novel orthosis using Carbon Fiber Reinforced Polymer (CFRP). The orthosis for ankle-foot is designed for rehabilitation of the patient from the foot drop disease. The orthosis’ shape is modelled to support the backside of the calf. It contributes to the maintenance of the gait cycle. In this paper, two different models of the AFO are compared, namely articulated and non-articulated. The finite-element analysis is done using the ANSYS software, and the results for equivalent Von-Mises stress as well as total deformation are observed and analyzed. Various materials are applied during the numerical analysis, as well as their combinations are tested.

Analyzing suspension upright of a Formula Society of Automotive Engineers style vehicle.

This project was aimed at modelling the stress and deformation profile of a 6061-T6 aluminium suspension upright of a formula society of automotive engineers style vehicle with a double wishbone suspension under the loading conditions of a 1.5G corner. With these results, it would need to be determined whether the design is fit for use. Using remote displacement boundary conditions for the upper and lower wishbone connections and the control arm connection with a remote force at the centre of the wheel patch acting on the bearing surfaces the maximum stress, overall stress profile and maximum deformation of the upright was calculated. These results after, undertaking a verification and validation study, were a maximum equivalent von-Mises stress of 87.358MPa and a maximum bearing surface deflection of 0.21 mm. The maximum von-Mises stress calculated was less than the fatigue limit of 90MPa signalling infinite life and also less than the yield stress of 240MPa signalling a safe design. Verification and validation techniques were used to ensure the final result was accurate and reflected the real – life system. Structural error was used to verify the results where it was found that maximum structural error in the upright was 0.052mJ and at the location of maximum stress was between 0.0058-1.0782e-8 mJ. Validation of the model was achieved by comparing the reaction forces calculated in ANSYS to theoretical values and was found that the magnitudes were within 2.5% of the theoretical values, thus the model was considered valid.

Critical role of scan strategies on the development of microstructure, texture, and residual stresses during laser powder bed fusion additive manufacturing

Laser based powder bed fusion additive manufacturing offers the flexibility to incorporate standard and user-defined scan strategies in a layer or in between the layers for the customized fabrication of metallic components. In the present study, four different scan strategies and their impact on the development of microstructure, texture, and residual stresses in laser powder bed fusion additive manufacturing of a nickel-based superalloy Inconel 718 was investigated. Light microscopy, scanning electron microscopy combined with electron backscatter diffraction, and neutron diffraction were used as the characterization tools. Strong textures with epitaxially grown columnar grains were observed along the build direction for the two individual scan strategies. Patterns depicting the respective scan strategies were visible in the build plane, which dictated the microstructure development in the other planes. An alternating strategy combining the individual strategies in the successive layers and a 67° rotational strategy weakened the texture by forming finer microstructural features. Von Mises equivalent stress plots revealed lower stress values and gradients, which translates as lower distortions for the alternating and rotational strategies. Overall results confirmed the scope for manipulating the microstructure, texture, and residual stresses during laser powder bed fusion additive manufacturing by effectively controlling the scan strategies. • Laser powder bed fusion additive manufacturing (L-PBF AM) of a nickel-based superalloy Inconel 718 was performed. • Influence of four scan strategies X-, Y-, alternating (X-/Y-) and rotational (67º) was investigated. • X-/Y- strategies developed textured columnar grains and alternating/rotational strategies reduced the texture. • Fine microstructure with weak texture led to the least residual stress development in alternating/rotational strategies. • Scan strategies can be manipulated to control microstructure, texture and residual stresses during L-PBF AM.

Effect of micro-defects on fatigue lifetime of additive manufactured 316L stainless steel under multiaxial loading

The statistical distribution of the geometric characteristics of microscopic defects, stress concentration factor (SCF) caused by microscopic defects and multiaxial fatigue lifetime of additive manufactured 316L stainless steel were investigated. The samples were machined after manufactured by Selective Laser Melting. Based on the X-ray computer tomography of typical 316L stainless steel specimen, the distribution laws of the geometric characteristics of microscopic defects in the material were studied, and the results indicated that the size and shape characteristics distributions of defects were subjected to lognormal rules well. The 3D volumetric models of typical microscopic defects under uniaxial, pure torsional, proportional and 90° non-proportional loading were imported into a finite element software to calculate SCFs caused by defects. The degree of stress concentration located at the edge of the microscopic defect under uniaxial loading was more serious than that under pure torsional loading with same nominal Von Mises equivalent stress (VMES). Simultaneously, greater SCF was arisen at the edge of microscopic defect under non-proportional loading instead of under proportional loading. The above conclusions were proved to be correct through analyzing the experimental data of additive manufactured 316L stainless steel under multiaxial fatigue loading. It showed that the fatigue lifetime under uniaxial loading was shorter than that under pure torsional loading with same nominal VMES. Meanwhile, the specimens subjected non-proportional loading had shorter fatigue lifetime than that under proportional loading with same nominal VMES.

Assessment of steel wire’s fatigue life using finite elements modelling and experimental testing

Various applications consist of wire rope as one of their most important construction parts. Wire ropes formed of three parts as basis; wires, strands and core. to get a deep understanding of wire ropes and their mechanical properties, it is essential to study their main part; the wire. For this reason, steel wire has been studied in this work to get its fatigue life as the number of cycles to failure using finite element modeling. FEM results have been verified using experiments; Flex tester machine and fatigue apparatus which is created and structured for this study. Outcomes have proved that using of bigger bending diameters resulted in increasing the fatigue life of the steel wire and vice versa. It is noticed that the FEM results have small and reasonable value of deviation comparing to the experimental results. Other mechanical properties of the steel wire have been obtained from FEM such as; equivalent Von-Mises stress, equivalent elastic strain, equivalent plastic strain and equivalent total strain.

The sensitivity of failure analysis of boiler tubes to the shape of elliptical external erosion flaws

Localized erosion is one of the most common failure mechanisms associated with boiler tubes, driven by impaction of the tube surface by fly ash, soot blowing steam, falling slag or other abrasive substances from the boiler’s combustion chamber. The tubes may experience significant localized reduction in their wall thickness, becoming susceptible to plastic collapse and bursting. The replacement of failed tubes is one of the leading causes of unplanned and forced boiler outages in process and power plants. In this study, geometric functions to enable the accurate modelling of boiler tubes with localized erosion flaws were developed from conceptualized models and finite element analyses were conducted on the modelled flawed tubes. The effect of geometry on the stress concentration in the tubes and on the failure pressure associated with the tubes was investigated. Linear elastic stress analysis is sensitive to the flaw geometry – for a representative problem stresses vary 38% as the flaw shape is varied. However, nonlinear elastic-plastic analysis shows significantly reduced sensitivity to flaw shape. The collapse pressure of the same representative problem now varies only 2.45% as the flaw shape is varied. This finding was demonstrated for various failure thresholds sourced from the literature, based either on plastic strain or Von Mises equivalent stress, which demonstrates that the failure of the tubes is insensitive to the specific choice of shape parameterization, as long as the minimum remaining wall thickness is matched. The outcome of these investigations gives further insight into the behaviour of tubes with localized external flaws while in service.

Static analysis of different spoke structure of airless and conventional tyre

An airless tyre is known as non-pneumatic tyres which are not advocated by air pressure. The major issues related to pneumatic tyre are puncture and flatness due to wear and tear, which lead to the development of airless tyres. The aim of this work is to conduct static analysis of airless tyre, considering various 3D printing materials with different spoke structures. The spoke structures like honeycomb, triangular and diamond and the 3D printing materials such as Acrylonitrile Butadiene Styrene + Polycarbonate (ABS+PC), Polyethylene Terephthalate (PET) and High Impact Polystyrene (HIPS) are considered for modelling of airless tyre. For conventional tyre, Neoprene rubber is considered. The static analysis is conducted using ANSYS workbench 19.2, and the total deformation, equivalent elastic strain, equivalent von-mises stress and strain energy are compared and evaluated for conventional and airless tyre.

Nanoindentation study and mechanical property analysis of nickel-based single crystal superalloys

Based on uniaxial tensile and compressive creeps, the mechanical properties of the third generation nickel-based single crystal superalloy were studied via the combination of nanoindentation, crystal plasticity theory, and finite element analysis. The Young’s moduli and hardness of γ, γ′ and the topologically close-packed (TCP) phases are related to chemical composition and applied stress. The maximum values of the Von Mises equivalent stress and damage are at the tip of the TCP phase. These values are inversely proportional to the distance to the TCP phase. Furthermore, the rafting of the γ′ phase can be predicted according to the distribution of the TCP phase and stress.

Compressive behavior of auxetic structural metamaterial for lightweight construction using ANSYS static structural analysis

Metamaterials are the class of man-made cellular structures that are intended to improve the energy absorption ability without an expense on its weight. The current investigation focuses on modeling and compressive simulation of three types of basic metamaterial (i.e Diamond, Auxetic and Hexagon) and its hybrids (i.e Auxetic-diamond, Auxetic-hexagon and Diamond-hexagon) with Ansys 19 simulation software. All the six auxetic metamaterials are simulated by assuming Polylactic Acid (PLA) material. At 0.1 MPa the maximum equivalent von-Mises stress was evident during the compressive analysis of auxetic-diamond hybrid structure. For auxetic-diamond hybrid structure higher energy absorption of 40 mJ was noted. It was observed to decrease by 67, 62, 75, 25 and 40% for auxetic, diamond, hexagon, auxetic-hexagon and diamond-hexagon respectively. The higher value of equivalent von-Mises stress and higher energy absorption is a manifestation of stiffest structure. The deformation results during simulation test confirmed that the basic auxetic structure and its hybrid absorb more energy. The hybrid auxetic metamaterials are the new class structural elements that exhibited extraordinary energy absorption ability.

Numerical Investigation on Human Knee Joint for Verifying Intactness of Anterior Cruciate Ligament

Magnetic resonance image (MRI) of a healthy human knee joint in full extension was considered for this study. A three-Dimensional geometry of the different parts of the healthy human knee joint is generated from the MRI. The geometry is discretized for various element sizes. The load was applied in two cases. In the first case, a 134-N load is applied to the joint in the posterior to the anterior direction for estimating anterior tibial translation (ATT) and the equivalent (Von-Mises) stress distribution in the model. As per the clinical practice, the intactness of ACL is ensured if the ATT is in the range of 3–10 mm. The results obtained from the analysis have ascertained the intactness of ACL in this study. In the second case, a 250 N is applied in the direction of gravity during the standing posture to obtain the equivalent (Von-Mises) stress distribution in the model. This analysis confirmed that the stresses in the joint are in the permissible limit of human endurance.

Assessment of non-uniform residual stress field of the thermal sprayed stainless steel coatings on aluminium substrates by the integral hole drilling method

Thermal spray is one of the most used techniques to produce coatings on structural materials. Such coatings are used as protection against high temperatures, corrosion, erosion and wear. The combined action of high pressures, temperatures and spraying conditions give rise to non-uniform residual stresses. The latter plays an important role in coating design and process parameters optimization. The present work highlights the influence of coatings thickness on the evolution of residual stresses in layered materials. Therefore, thick stainless steel coatings (ASTM 301) of different thicknesses are manufactured by wire arc spraying on aluminium alloy substrates (ASTM 2017A). For a better bond strength, a Ni–Al bond coat is first deposited. Furthermore, a numerically supported hole drilling strain gage method for residual stress field evaluation is proposed. Required calibration coefficients, for the strain–stress transformation formalism based on the integral method, are computed through finite element calculations using Abaqus software. The results indicate that the maximum residual stresses, for all thicknesses, are tensile and range from 140 to 275 MPa. The bond coat does not seem to affect the stress field. Also, it was found that the mean equivalent Von-Mises stress decreases with increasing coating thickness; hence reducing the interfacial adhesion energy of the sprayed materials.

Finite Element Study of Hard and Soft Inclusions in Hard/soft Matrix

Hard inclusions in the soft matrix are common in metal matrix composites. On the other hand, soft inclusions in the hard matrix can be found for instance in plastics like acrylonitrile-butadiene-styrene (ABS). This work focuses on the finite element study of hard inclusions in the soft matrix and soft inclusions in the hard matrix. Equivalent von-Mises Stress and Equivalent plastic strain are evaluated. Hard inclusions in the soft matrix produces higher plastic deformation than soft inclusions in the hard matrix but stresses are higher for soft inclusions in the hard matrix than for soft inclusions in the hard matrix along with plastic deformatio

Influence of Emergency Stop Operation for Strength of Brazed Structure With Rectangular Fins and Plates in Liquefied Natural Gas Heat Exchanger

Abstract In order to ensure the structural safety of a liquefied natural gas (LNG) heat exchanger in emergency stop operation process, the strength of a brazed structure with rectangular fins and plates is investigated by means of the finite element method. The microstructure of brazed joints and brazing filler is tested by metallographic examination with a scanning electron microscope (SEM). The results show that the maximum shear stress is the main reason for the structural failure at the brazing seam while the brazed joint is mainly subjected to the maximum normal stress. The peak value of the Von Mises equivalent stress in brazed structure with rectangular fins and plates linearly increases with the HMR pressure when the temperature difference is less than 10 K between HMR and LMR. At the same time, the peak value of Von Mises equivalent stress also increases with the equilibrium temperature and temperature difference between LMR and HMR. The aggregation of the elemental Si in the brazed joints and brazing seam will exacerbate the structural safety of the brazed structure in the emergency stop operation process. The above results provide some constructive guidance for the emergency stop operational process for an LNG heat exchanger.

Performance Analysis of Gudgeon Pin of Various Cross Sections by FEM

Gudgeon pin are one of most heavily stressed component present in engine Gudgeon pin is used in automobile engines to connect piston and connecting rod. and its failure can cause seizure of the engine. Thus they are carefully designed. This project deals with gudgeon pin of different inner profiles keeping the outer diameter constant which is equal to piston boss to provide a more strengthen gudgeon pin. Profiles investigated are hollow, uniform stepped, tapered, step taper. The models with mentioned inner profiles keeping outer profile straight are made using CATIA and then analyzed for using ANSYS for parameters maximum principal stress, equivalent (von-mises) stress, strain energy and total deflection. Considering all these parameters most suitable design of gudgeon pin is decided. On investigation of the different profile it was found that step taper profile gave the best results .Thus providing a stronger gudgeon pin leading to decrease in chances of failure.

Fluid Structure Interaction Analysis of Horizontal Axis Wind Turbine

Wind power is a clean energy source that we can rely on for long term use. A wind turbine creates reliable, cost effective pollution free energy. A Horizontal axis wind turbine (HAWT) with three blades having aerofoil profile NACA 2421 is modelled in CAD software and the performance of the turbine is investigated numerically using 3D CFD Ansys 18.1 software at rotor speeds varying from 1 to 7.5 Rad/sec at wind speeds ranging from 8 to 24 m/s. In order to ensure the turbine blades do not fail due to pressure loads and rotational forces, Fluid structure interaction is carried out by importing the surface pressure loads from CFD output on to static structural module, the rotational velocities are also imparted on the blades and FE analysis is carried out to estimate the equivalent von-Mises stress for structural steel as well as aluminium alloy. It is found that aluminium alloy blades are preferable than the structural steel blades. At high rotor speeds, stresses in the structural steel exceeding the yield strength limit. For aluminium alloy the stresses are below the yield strength limit.

Numerical analysis for stress fields induced by laser trepanning of square-slotted blind holes with and without ultrasonic assistance

The numerical simulation on laser trepanning of square-slotted hole and hole array in stainless steel sheets with and without ultrasonic assistance was reported for analyzing the stress fields on the workpieces trepanned. Based on reasonable modification and verification for the established models using corresponding experimental results, the transient and/or residual stress distribution characteristics, which were induced by single hole trepanning and hole array trepanning with and without ultrasonic assistance, were analyzed systematically and numerically using finite element method (FEM) coupled with self-developed subprograms after predicting the transient temperature fields. The influence of ultrasonic assistance on stress reduction was also discussed. It was shown that the distribution characteristics of equivalent von-Mises stress fields on the top surface of laser trepanned workpiece were different from those on its corresponding bottom surface. For laser-trepanned workpieces, the residual stress distribution characteristics predicted after sufficient cooling were different from the corresponding transient stress characteristics simulated without sufficient cooling. As a whole, the ultrasonic assistance resulted in a small change for the distribution trend of the transient/residual stress field predicted, while the influence of ultrasonic-induced softening effect on laser trepanned workpiece was primarily demonstrated by the effective reduction of the stress values.

Effects of overdenture attachment systems with different working principles on stress transmission: A three-dimensional finite element study.

PURPOSEThe aim of the present study was to compare the stress distributions on the dental implants, abutments, and bone caused by different overdenture attachment types under functional chewing forces.MATERIALS AND METHODSThe 3D finite element models of the mandible, dental implants, attachment types, and prostheses were prepared. In accordance with a conventional dental implant supported overdenture design, the dental implants were positioned at the bone level in the canine teeth region bilaterally. A total of eight models using eight different attachment systems were used in this study. All the models were loaded to simulate chewing forces generated during the centric relationship (450 N), lateral movement (400 N), protrusive movement (400 N), and also in the presence of a food mass unilaterally (200 N). Stress outputs were obtained as the maximum principal stress and the equivalent von-Mises stress.RESULTSIn all attachment types, higher stress values were observed in the abutments, dental implants, and bone in the magnet attachments in different loading conditions. The highest stress values were observed among the magnet systems in the components of the Titanmagnetics model in all loading conditions (stresses were 15.4, 17.7, and 33.1 MPa on abutment, dental implant, and bone, respectively). The lowest stress value was observed in the models of Zest and O-Ring attachments.CONCLUSIONThe results of the present study implied that attachment types permitting rotation and tolerating various angles created lower stresses on the bone, dental implants, and abutments.

A finite element analysis to study the stress distribution on distal implants in an all-on-four situation in atrophic maxilla as affected by the tilt of the implants and varying cantilever lengths.

Aim:The aim of this work was to evaluate stress distribution on implants in All-on-Four situation with varying distal implant angulations (30°,40°,45°) and varying cantilever lengths (4 mm, 8 mm, 12 mm, 16 mm) in atrophic maxilla using finite element analysis.Setting and Design:A in vitro study, finite element analysis.Materials and Methodology:Three-dimensional finite element model of an edentulous maxilla restored with a prosthesis supported by four implants was reconstructed to carry out the analysis. Three different configurations, corresponding to 3 tilt degrees of the distal implants (30°, 40°, and 45°) were subjected to 4 loading simulations.Statistical Analysis Used:The results of the simulations obtained were evaluated in terms of Von Mises equivalent stress levels at the bone-implant interface.Result:From a stress-level viewpoint, the 45° model was revealed to be the most critical for peri-implant bone. In all the loading simulations, the maximum stress values were always found at the neck of the distal implants. With increasing distal implant tilt, cantilever length reduces depending on the quality of bone. At 30° angulation of distal implant a maximum cantilever length of 16 mm may be given if the quality of bone is D3 but only 8 mm cantilever may be recommended if bone quality is D4. At 40° angulation, 16 mm in D3 bone and 0 mm in D4 bone whereas at 45° angulation, it reduces to 12 mm in D3 bone and no cantilever is recommended with D4 bone.Conclusion:The 45° tilt induced higher stress values at the bone-implant interface, especially in the distal aspect, than the other 2 tilts analyzed. Stress values increased with increased cantilever length which was further influenced by the distal implant tilt and the quality of the bone.

Analysis and Evaluating of Flexible Ankle Foot Orthosis for Drop Foot Deformity

This work involved two major parts: the first Part is the experimental part included manufacturing ankle foot orthotics, measure the (the reaction force of the ground, pressure distribution) for both normal (healthy) and sound side (intake) legs in two case, the first measurement when the patient walking without orthosis while the second test when the patient dressed up the flexible (AFO). The pressure generated between leg and calf part is measured by F-Socket devise. The experimental part also consist test the mechanical properties of a suggestion composite material. The second Part is the (FEM) finite element analysis for numerical simulation part during which the stresses are calculated using ANSYS 14.5 software. Experimental work was done on a case study suffering from low level spinal cord trauma he has good control of the trunk muscles but the muscle weakness and nerve damage for right leg. The patient with age, weight of 30years, 75kg, respectively. The Results show the parameters of test for both legs (left and right) in two cases. The results show that the data of the gait cycle in the case of the patient wearing the brace is more acceptable and we notice improvement in the performance of walking steps and reduce the difference between the infected leg and natural and this indicates the good evaluation of this orthosis. Max pressure obtained is 1.53*10^5MPa from F .Socket at calf region .Max stress Calculated at Posterior ankle joint because it is flexible Position The equivalent Von-Mises stress and the safety factor for fatigue of the composite material gave good results this led to the longer life design.