Equivalent Stress Strain Research Articles

Weight Reduction of Air Filter Assembly Using the Composite Material

Air filtering systems are inevitable part of a controlled volume vessel and its vitality increases with increasing on-board time. However, using bulking CF filters adds to add weight of vessel which further decreases the efficiency of the air filter. For the present work, composite material made from E-glass, silenka with honeycomb structure is chosen. The study involves the generation of the 3D model on Solid- works and then performing the analysis on the model using ANSYS 2019R1 software. A new composite material using honeycomb structure of E-glass, Silenka laminate is generated which is effective in cost saving as well as delivers good results against stresses. The composite laminate was successfully implemented on to the 3D model generated with weight reduction approach, the 45.86% of the dead -weight is reduced which would be very effective to raise the efficiency of the submarine and other industrial plant.With comparative strength approach, 55.78% increment in the tensile strength is achieved in computational analysis, impact test shows 2.28%, 25.90% and -82.13% change (for respective maximum values) in Max. deformation (mm), Equivalent Stress and Equivalent Elastic Strain during impact test as compared to Stainless steel using ansys.

Multi-strut and empirical formula-based macro modeling for masonry infilled RC frames

It is widely accepted that infill walls play an important role in the structural response of buildings under seismic excitations. Disregarding their influences on the seismic design and evaluation of structures could be potentially dangerous. Therefore, a reliable numerical model is necessary. Because of its simplicity and efficiency, the equivalent strut model is the most widely used to represent infilled frames. In this study, a novel multi-strut macro model and associated empirical formulas for modeling infilled RC frames are proposed. The model was developed based on previous experimental observations. Fiber-section truss elements are used as the struts. All potential failure modes of the infill wall were considered by means of the equivalent stress–strain parameters of the struts. Empirical formulas for predicting these equivalent stress–strain parameters were developed and calibrated based on a comprehensive experimental database and regression analysis. Finally, blind validation tests of the proposed model and empirical formulas were performed to assess their reliability. Monotonic and cyclic load simulations of the infilled RC frames were carried out and compared with experimental results. The application of the proposed approach for both single-bay and multi-bay infilled frame simulations was examined.

Determining reliable wide-strain-range equivalent stress–strain curves using 3D digital image correlation

We propose a method for obtaining reliable wide strain range equivalent stress–strain curves from tensile testing by applying 3D digital image correlation. Herein, both the front and side surfaces of the specimen were identified by the 45° tilting of the specimens. The deformation of the specimen was the most severe in the neck section, and the equivalent strain representing the entire specimen could be extracted from the neck regions on the side and front surfaces. In addition, the equivalent stress was obtained by calculating the reduction in the varying cross-sectional area from the strain information of the two surfaces. The resulting wide strain range equivalent stress–strain curves can describe nonlinear hardening behaviors up to higher strains than the conventional gauge length method. The proposed method can provide wide strain range equivalent stress–strain curves only through experiments without requiring separate finite element method simulations or correction factors.

PH-responsive hierarchically porous self-assembly bioinspired Al2O3 ceramic membranes

In this work, we present a preparation strategy for pH-responsive hierarchically porous bioinspired Al2O3 ceramic membrane (pH-HPBA-CM). The pore size of the pH-HPBA-CM could be adjusted by altering the pH value. With the increase of the pH value, the porosity gradually decreases and the compressive strength of the pH-HPBA-CM is also affected by the pH value, which presents an increasing trend with the increase of the pH value. The variation of compressive stress versus displacement of the pH-HPBA-CMs (stress-strain relationship) prepared at different pH values was discussed. A mechanical simulation experiment was carried out to better analyze the reason why the honeycomb-like structure of the pH-HPBA-CM has excellent specific strength. In the simulation process, the small pore model (15 μm) can be regarded as part of the large pore model (35 μm). The simulation of the total deformation, equivalent stress, and equivalent elastic strain were obtained by setting the load pressure of 100 MPa. At this load pressure, the maximum deformation of the entire ceramic membrane is far lower than the theoretical limit value of its simulation, and all of them are distributed at the junction (connectional pores). This work provides a new insight into the effective preparation of pH-responsive hierarchically porous bioinspired ceramic membranes with high porosity, excellent mechanical performance, and tunable pore size.

Determination of Assumed Strain Hardening Relationship from Shear–Compression Model and Data Analysis

A new method for obtaining equivalent stress–strain curves of bilinear and Swift law material models from the numerical results of shear–compression test (SCT) is developed. This task is conducted on the basis of the approximate analytical relations for the compression and shear conditions at the gauge section and by the application of correction factors. Logarithmic correction models are developed and used to generalize the geometry of an optimum shear–compression specimen (SCS) that is calibrated by one-factor-at-time method for a reference material. Furthermore, a dataset created from 125 finite element simulations is analyzed by data analysis techniques, and a universal nonlinear strain hardening relationship is determined. This model is used to predict the stress–strain curves directly from the force–displacement curve of the SCS. The input and output stress–strain curves are in good agreement with an average error of approximately 3%. The numerical findings of this study provide a foundation to develop a general quantitative relationship to study the behavior of materials by SCT.

Finite element analysis of the thermo-mechanical fatigue of DD8 single crystal nickel-based superalloy

Abstract A nonlinear finite element method is presented for analysing the thermo-mechanical fatigue behavior of the DD8 single crystal nickel-based superalloy. The specimens had axial orientations along the [001] direction. In-phase and out-of-phase thermo-mechanical fatigue were simulated under mechanical strain control with a temperature variation from 450 to 900 °C. The cyclic mechanical behavior, the equivalent stress and plastic strain were investigated in both γ' phase and γ matrix.

Dynamic constitutive model of U75VG rail flash-butt welded joint and its application in wheel-rail transient rolling contact simulation

Rail welded joint is one of weak links in high-speed railway, and its dynamic performance has important effects on the safety, stability, and comfort of the high-speed train. In this work, the dynamic mechanical responses at different regions of U75VG rail flash-butt welded joint were investigated. The results show that the base metal (BM), welding zone (WZ), and heat-affected zone (HAZ) of U75VG rail flash-butt welded joint has an obvious strain rate effect, i.e., the material strength increases with increasing the loading strain rate. The strength of WZ is similar to that of BM, but its toughness is much lower than that of BM. The toughness of HAZ is the same as that of WZ, but its strength is much lower than that of BM and WZ. Based on the experimental results, an improved dynamic constitutive model was established to reasonably simulate the stress–strain curves of different regions from quasi-static loading to dynamic loading. Finite element (FE) analysis of transient rolling contact between rail welded joint and wheel under different conditions was performed. Compared with the results from quasi-static wheel-rail contact simulation, the equivalent plastic strain at each region of rail welded joint increases significantly and presents non-uniform distribution after considering the dynamic effect. When the wheel contacts the junction between different regions, the impact will cause a significant stress concentration at the rail welded joints. The maximum wheel-rail load by the implicit dynamic analysis is about 4 ∼ 12 times that obtained by the quasi-static analysis. Moreover, the maximum contact pressure, equivalent stress and equivalent plastic strain of each area of rail welded joints gradually increase with the increase in axle load and driving speed.

Numerical analysis of WaveOne Gold and 2Shape endodontic files during root canal treatment.

This study aims to develop and analyse a finite element model of the endodontic nickel-titanium (NiTi) instrument during the root canal treatment (RCT). The 3D model of the tooth and the endodontic instrument has been created using computer-aided design software. The nonlinear explicit dynamic analysis in the CAE package (ANSYS) has been used to analyse the mechanical behaviour of endodontic instruments such as total deformation, equivalent elastic strain, and equivalent stress during canal preparation. The mechanical behaviour of three commercially available endodontic NiTi alloy instruments such as WaveOne Gold (WOG), 2Shape 1 (TS1) and 2Shape 2 (TS2) endodontic files was evaluated using FEA. Consequently, the effect of deformation, equivalent stress and equivalent elastic strain on endodontic files during cleaning and shaping are investigated and compared. The results show that the total deformation and equivalent elastic strain are maximum in the TS1 endodontic file in comparison to TS2 and WOG files.

Numerical and Experimental Studies on Hydro-Forming of a Thin Metallic Disc

This paper deals with the hydro-forming of a flat thin metallic disc to achieve a forward domed disc which will be subsequently adopted to manufacture a rupture disc. The plastic deformation induced by the hydraulic energy is numerically simulated through an isotropic hardening plasticity model using a non-linear explicit finite element analysis (FEA). The variation in disc’s central deformation, thickness, equivalent plastic stress and equivalent plastic strain with respect to the applied hydraulic pressure are determined from FEA simulations. The hydro-forming setup is then designed and manufactured, and the metallic disc is experimented under hydro-forming process. The reduction in thickness due to stretching of the thin disc is evaluated from experiment and simulation and a close agreement is found. This research attempt helped in finalizing the hydro-forming fluid pressure, the feasibility and the accuracy of practically achieving the desired geometry of the metallic disc. The near-fixidity effects on abrupt variation in sheet thickness and plastic strain are well captured through simulations which are very difficult to be studied through hydro-forming experiments.

Design and analysis of piston using aluminum alloy and composites in Solidworks and Ansys

The present paper reports the modelling and analysis of piston fabricated from Steel, Aluminum alloy and Composites for 4-stroke petrol engine of a specific version followed by comparison between the both. Solidworks software is used for 3D modelling of the piston. Ansys software is used for static structural and steady state thermal analysis of the piston. A static-structural analysis is being performed to find out the deformation, stresses, strains, and forces in structures or factors caused by the loads. A static analysis calculates the impact of steady loading conditions on a structure, while ignoring inertia and damping as those carried by time varying loads. Steady state thermal analysis is used for evaluating the thermal equilibrium of a system in which the temperature remains constant over time. Steady-state thermal analysis can be used to determine the temperature distributions in an object with thermal loads that do not vary with time. The heat transfer includes conduction, convection and radiation. Most thermal analyses are steady state thermal analyses. Total Deformation, Factor of Safety (F.O.S.), Equivalent (Von-mises) stress and Equivalent (Von-mises) strain were obtained under static structural analysis for piston using different materials. Total heat flux, Directional heat flux and temperature distribution were obtained using steady state thermal analysis. Performance of standard material used for piston and aluminum alloys was compared and the best material was recommended for manufacturing of piston.

Influence of Crystal Plasticity Parameters on the Strain Hardening Behavior of Polycrystals

The effective mechanical properties of a polycrystal depend directly on the single-crystal properties of each grain and its crystallographic orientation with respect to the load axis. While the micromechanical approach has been used quite extensively to study the influence of grain shape and crystallographic texture on the resulting mechanical behavior of a polycrystal, the influence of the crystal plasticity parameters, which describe the constitutive behavior of the single crystal, requires to be investigated systemically because, typically, these parameters are fitted to describe a given material behavior. In the current research, this gap is filled by systemically studying the effect of changes in crystal plasticity parameters on the effective mechanical properties of polycrystals. The numerical model employed here consists of a representative volume element of 100 grains, and the material properties are described by using a non-local crystal plasticity model. A proper homogenization technique was used to homogenize the micromechanical results to an effective macroscopic material response. The equivalent stress versus equivalent plastic strain curve was obtained numerically by introducing the Voce-type hardening law, mimicking the material behavior in uniaxial tensile tests. The four parameters of the Voce-type hardening law were fitted to the macroscopic stress-strain curves, and the correlation between the crystal plasticity parameters and the Voce parameters has been studied, which is an efficient way to study the influence of microscopic material descriptions on the macroscopic behavior of polycrystals.

Analytical elastoplastic model for stress and strain of the equivalent representative volume element and material testing application

For unidirectional loaded specimens consisting of isotropic-homogeneous ductile materials, an analytical elastoplastic model for the equivalent stress and strain of the representative volume element at the median point were derived based on energy density equivalence and dimensional analysis. Then, a data processing method for various specimen types was proposed to obtain the equivalent stress–strain in real time without presetting the constitutive parameters. Finite element analyses of six specimen types and experiments with four selected specimen types were conducted to verify the method. The results show that the stress–strain curves obtained using this method were consistent with the preset stress–strain curves in the finite element analysis and with the standard tensile results. Using the proposed model and relevant data processing method to obtain the stress–strain curves is effective and, with the theoretical basis, could promote the application of non-tradition and small specimens for obtaining the material mechanical properties.

A two-dimensional ordinary state-based peridynamic model for plastic deformation based on Drucker-Prager criteria with non-associated flow rule

The plastic behaviors of geomaterials often obey non-associated flow rule. In this paper, a two-dimensional (2D) ordinary state-based peridynamic (OSB-PD) increment model with shear deformation based on Drucker-Prager (D-P) criterion with non-associated flow rule is proposed to study the plastic behavior of geomaterials. An incremental form of peridynamic (PD) strain energy density for plane elastic problems is first established. The material parameters are determined when the incremental PD strain energy density is equal to the incremental strain energy density in classical mechanics. The PD force density for the OSB-PD theory with shear deformation in plane elastic cases is derived accordingly. The relationship between the incremental second invariant of the stress tensor dJ2, the first invariant function of stress tensor dI1 in the classical mechanics and PD are established in this paper, and the Drucker-Prager yield surface is expressed in the framework of peridynamics. To avoid the excessive plastic dilation, the non-associated flow rule is proposed, in which isotropic and deviatoric plastic elongation are employed to describe the plastic behaviors of a bond. Also, the equivalent stress and equivalent plastic strain for the proposed PD model are given. An integration algorithm for the proposed increment model is developed. Numerical examples including circular opening in rocks are performed, and the PD results are compared with that obtained by the finite element method or analytical solution. Those numerical simulations have verified the validity of the proposed PD model to predict the elasto-plastic behavior of geomaterials.

Structural Analysis on the Coil Spring of Motorcycle Suspension System

The motorcycle suspension system is one of the crucial components. It helps to support the motorcycle’s weight, isolate the vibration level caused by road imperfection, and keep the wheel in contact with the road surface. Therefore, the performance of suspension system needs to be enhanced to ensure the ride comfort and safety of riders. Coil spring is one of the essential parts of motorcycle suspension system. In this study, two different materials of coil spring are being focused include steel alloy and carbon fiber reinforced plastic (CFRP). The geometry of the coil spring is the existing design in the market. The static structural analyses are carried out to determine the directional deformation of y-axis, equivalent stress and equivalent elastic stress analysis of the corresponding coil spring material. The obtained results are discussed. It is found that the steel coil spring has better performance for the existing coil spring design. The directional deformation, equivalent stress and equivalent elastic strain of steel coil spring are considered at the lower side, which is 0.029357mm, 2003MPa and 0.010051mm/mm respectively. In this study, it is observed that the number of turns of coil spring should be increased to enhance the performance of CFRP coil spring.

Analysis and Evaluation of Optimized Lower Limb Prosthetic Device

Transtibial prosthetic devices or below-knee prosthetic devices are used as assistive devices in replacing the part of the leg below the knee joint in case of amputation. The different builds in amputees require the need for the accessibility to custom-made lucrative prosthetic devices in order to reintegrate the amputees into society. The goal of this study is to design a personalized transtibial prosthetic device that closely mimics the human gait by the use of topology optimization. Additive manufacturing is used to reduce the fabrication time of a traditional transtibial prosthetic device. The creation of the transtibial prosthetic device model is through computer-aided drawing (CAD) and afterwards simulated using ANSYS for the comparison and contrasting of the optimized design. The materials used in the design of the transtibial prosthetic device are polypropylene and titanium alloy. Simulation works reveal that there is a 12.8% reduction in the minimum equivalent (von-Mises) stress and a 51.29% reduction in the minimum equivalent elastic strain of the benchmark socket, and titanium alloy is the superior material in the fabrication of prosthetic foot as it greatly reduced the total deformation, equivalent (von-Mises) stress and equivalent elastic strain of the SACH foot as compared to polypropylene in the initial contact, midstance and the push-off phases of the gait cycle. Topology optimization of both the socket and foot models reduced the stiffness and density of material volume up to 60%. Voronoi pattern developed on the socket and foot models mirrors the reduction done on material volume by topology optimization.

Development of a coupled numerical framework of steel fiber reinforced self-compacting concrete

A coupled numerical framework comprised of a computational fluid dynamics (CFD) based method and a finite element method is presented in this paper to model the steel fiber reinforced self-compacting concrete (SFRSCC). The computational fluid dynamics based method is applied to simulate the casting process of fresh SFRSCC to determine the coordinates of the steel fibers, which are used as input to the finite element model of hardened SFRSCC specimens. In the finite element model, SFRSCC is assumed to be a heterogeneous medium consisting of a homogeneous phase (concrete matrix) and a discrete phase (steel fibers). The nonlinear behavior of the concrete matrix is modelled by the continuum damage plasticity model, while the steel fibers are explicitly modeled as discrete truss elements. In order to take into account the fiber pull-out response, the equivalent stress–strain laws derived from an analytical load-slip curve are assigned to the steel fibers depending on their orientation angles. To verify the numerical framework, the casting process and four-point bending tests of the SFRSCC beam specimens were numerically simulated. The good agreement with the simulated and experimental results proves the feasibility of the proposed numerical framework.

Manufacturing and Characterisation of Polymeric Membranes for Water Treatment and Numerical Investigation of Mechanics of Nanocomposite Membranes.

In this study, polyethersulfone (PES) and polyvinylidene fluoride (PVDF) microfiltration membranes containing polyvinylpyrrolidone (PVP) with and without support layers of 130 and 150 μm thickness are manufactured using the phase inversion method and then experimentally characterised. For the characterisation of membranes, Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and pore size analysis are performed, the contact angle and water content of membranes are measured and the tensile test is applied to membranes without support layers. Using the results obtained from the tensile tests, the mechanical properties of the halloysite nanotube (HNT) and nano-silicon dioxide (nano SiO2) reinforced nanocomposite membranes are approximately determined by the Mori–Tanaka homogenisation method without applying any further mechanical tests. Then, plain polymeric and PES and PVDF based nanocomposite membranes are modelled using the finite element method to determine the effect of the geometry of the membrane on the mechanical behaviour for fifteen different geometries. The modelled membranes compared in terms of three different criteria: equivalent stress (von Mises), displacement, and in-plane principal strain. Based on the data obtained from the characterisation part of the study and the numerical analysis, the membrane with the best performance is determined. The most appropriate shape and material for a membrane for water treatment is specified as a 1% HNT doped PVDF based elliptical membrane.

A new design method of the equivalent stress–strain relationship for hybrid (FRP bar and steel bar) reinforced concrete beams

Hybrid reinforced concrete (hybrid-RC) beams consisting of fiber-reinforced polymer (FRP) bars and steel bars can provide high strength, serviceability, and durability. However, based on a review of the literature, the design methods for hybrid-RC beams fail to effectively predict the flexural failure mode of these structures. Therefore, an equivalent constitutive relationship is proposed, which considers the FRP bar and steel bar as a new material with a bilinear constitutive relationship. Two balanced reinforcement ratios were introduced in the design method, which can accurately predict the failure mode of both the hybrid-RC structure and FRP strengthened RC structure. The feasibility of the proposed method was then confirmed by experimental testing.

Surface roughness analysis of medical grade titanium sheets formed by single point incremental forming

Single point incremental forming (SPIF) process has proven benefits in terms of formability, flexibility, and low cost as compared to conventional sheet forming, although it has some issues such as dimensional accuracy and low quality of surface finish for some materials. The SPIF is considered as a potential method of producing customised medical parts such as craniofacial implants using a titanium sheet. This investigation aims to analyse the overall surface roughness of grade 1 pure titanium along the wall of the hyperbolic truncated cone formed by the SPIF process with different forming parameters (i.e. forming tool diameter, step size, and feed rate). Focus variation microscopy was used to measure the surface roughness experimentally along the wall of the truncated cone. Abaqus/Explicit was used to predict the equivalent stress and equivalent plastic strain along the wall of the truncated cone part from the top to the fractured region to evaluate the relationship between the stress, strain, and roughness distribution. It was found that the surface roughness changes with the deformed part height and rough surface could be produced in the region of high equivalent stress and low equivalent plastic strain. Such a surface roughness and equivalent stress and plastic strain correlation has a clear implication to the design and the surface quality of sheet parts made by SPIF.

Modelling & Static Analysis of Automotive Wheel Rim using different materials

In this paper, we compare equivalent stress, Total deformation and equivalent elastic strain in 19-inch wheel rim of MG Gloster by Finite element method. The need of Wheel Rim is to get the stable base on which the tyre mounted. It should acquire the tyre as per the size, dimension, and shape required for the vehicle. Modelling of the rim was done by using 3-D modelling software SOLIDWORKS 2019, whereas the static structural analysis was done by using ANSYS R2 2020. ANSYS WORKBENCH R2 2020 is the software used for regular testing and simulation of materials used for the wheel rim to get the required calculations and result. ANSYS WORKBENCH R2 2020 performed the structural analysis by the material used are structural steel, carbon fiber (Low Grade), Kevlar 29, E-Glass, S-Glass, basalt, Al 6061 T6 and High Strength Low Alloy steel, their relative performances have observed respectively. The analysis is carried out for tyre inflation pressure, rotational velocity and moment condition. This analysis carried out to find the best material out of the listed materials for the wheel rim that gives optimum results for making an effective rim structure.