Stress-strain Analysis Research Articles

Analysis of stress-strain state of bogie frame of PE2U and PE2M industrial traction unit

This article presents the results of the theoretical analysis of the stress-strain state of the industrial traction unit PE2U and PE2M frame. The stress-strain analysis was performed using the finite element method in SolidWorks Simulation software. The analysis results are necessary to estimate the residual resource of the traction units at the end of their service life and extend their service life. According to the requirements of the state standards, to extend the service life of the rolling stock load-bearing constructions, the stress-strain state of these constructions should be studied. A 3D model of the bogie frame was built using SolidWorks software to evaluate the strain-deformation state. Using the SolidWorks Simulation program, the stress-strain state of the bogie frame was evaluated using the finite element method based on the Palmgren–Miner–Mises theory. All static and dynamic loads in use affecting the bogie frame are taken into account.

Stress–strain analysis of vertical shaft lining and adjacent rock mass under conditions of irregular contour

Stress–strain analysis of vertical shaft lining and adjacent rock mass under conditions of irregular contour

Predictive stress–strain analysis of tailings dams from 3D FEM-based model

Predictive stress–strain analysis of tailings dams from 3D FEM-based model

Study on stress-strain effect on gas production from shale formation

The extent of gas production from shale reservoirs depends heavily on the stress-strain impact on the reservoir. The reservoir's developed stress allows the rocks to fracture naturally. The developed fractures across the reservoir blocks enhance the gas flow from the reservoir towards the wellbore. This review paper provides a comprehensive overview of the technologies and engineering of shale formation permeability behavior and the impact of induced stress and strain. The impacts of stress and strain on the permeability of shale are also studied. This paper presents the effect of stress-strain analysis on gas recovery due to various gas injections, the dependence of gas shale fracture permeability on effective stress and reservoir pressure, analyzing the consequences of various gas injection rates on stress and strain, and the result of stress-strain elongation or variation on hydrocarbon recovery.

Research on a tubeless tire for a mobile robot

Airless tires are used not only in cars, but also in vehicles used in the construction, road, forestry, and robotics industries. In order to develop the construction of an airless tire, its optimization at the stage of their design, a comprehensive method of researching the operational properties of an airless tire is proposed. The methodology includes stress-strain analysis, modal and thermal analysis of an airless tire using three-dimensional modeling using the finite element method. The airless tire was studied in the following modes of uniform movement of the wheel on a solid base: driven wheel; driving wheel; free wheel; neutral wheel; brake wheel. An example of the study of an airless tire of a mobile robot is given.

Fabrication of sustainable green bricks by the effective utilization of tannery sludge as main additive

The existing practice of manufacturing construction bricks consumes the maximum amount of natural resources leading to their depletion and severe environmental degradation. The utilization of industrial waste materials is a plausible alternative and is the vision of the Indian government under the waste-to-wealth concept. In the present work, industrial byproducts such as tannery sludge, fly ash, Ground Granulated Blast Furnace Slag (GGBS), and lime were used to develop sustainable green bricks (SGBs) without the need for burning. In the fabrication of SGBs, a combination of lime, fly ash and GGBS was used as binder material. Tannery sludge was replaced up to 30 % in the binder mix, and the optimized mix was used to prepare mortar, followed by solidification and stabilization. Finally, SGBs were water cured with and without prior carbonation. The characteristics of bricks such as microstructure, dry weight, compressive strength, and durability properties like sorptivity, leachability, water absorption and efflorescence were studied. They were comparable to conventional first-class bricks as per the Indian Standards. The compressive strength of the SGBs containing 20 % tannery sludge and 80 % of binder mix (containing 20 % GGBS, 30 % lime and 50 % fly ash) cured with and without carbonation was found to be 8.81 N/mm2 and 7.62 N/mm2; which is 2.5 and 2.17 times respectively, more than conventional first-class bricks (3.50 N/mm2). The elastic modulus of the carbonated specimen was 3.3 times higher than the non-carbonated mortar specimen, as determined by stress–strain analysis. The increase in the compressive strength was evidenced by the results of various techniques such as Scanning Electron Microscopy (SEM), X-ray Diffraction (XRD), Mercury Intrusion Porosimetry (MIP), Energy Dispersive Spectroscopy (EDS), and Thermogravimetric Analysis (TGA). Our results demonstrate that sustainable green bricks could serve as a better replacement for clay bricks and emerge as a carbon-negative material.

Preventing extrinsic mechanisms of bioprosthetic degeneration using polyphenols.

The purpose of this study was to evaluate the impact of a polyphenols-based treatment on the extrinsic mechanisms responsible for early bioprosthetic heart valve (BHV) degeneration. Structural degeneration can be driven by both extrinsic and intrinsic mechanisms. While intrinsic mechanisms have been associated with inherent biocompatibility characteristics of the BHV, the extrinsic ones have been reported to involve external causes, such as chemical, mechanical and hydrodynamic, responsible to facilitate graft damage. The chemical interaction and the stability degree between polyphenols and pericardial tissue were carefully evaluated. The detoxification of glutaraldehyde in commercial BHVs models and the protective effect from in vivo calcification were taken into relevant consideration. Finally, the hydrodynamic and biomechanical features of the polyphenols-treated pericardial tissue were deeply investigated by pulse duplicator and stress-strain analysis. The study demonstrated the durability of the polyphenols-based treatment on pericardial tissue and the stability of the bound polyphenols. The treatment improves glutaraldehyde stabilization's current degree, demonstrating a surprising in vivo anti-calcific effect. It is able to make the pericardial tissue more pliable while maintaining the correct hydrodynamic characteristics. The polyphenols treatment has proved to be a promising approach capable of acting simultaneously on several factors related to the premature degeneration of cardiac valve substitutes by extrinsic mechanisms.

Implementation of Mechanistic-Empirical Pavement Design Guide against Indonesian Conditions using Arizona Calibration

Background: As a transportation infrastructure that connects one area to another, roads have an essential role in economic and social growth, together with establishing a location that may improve the quality of life in the surrounding community. For this reason, it is necessary to perform road maintenance when the structural or functional capacity of the road is inadequate, one of which is by overlaying the road. Objective: The main objective of this research is to determine the thickness of the flexible pavement overlay and subsequently examine the damage model produced by the 2015 MEPDG method with Arizona calibration. This study also proposes recommendations for implementing the 2015 MEPDG procedures in Indonesian settings. Methods: The thickness of the road overlay can be designed through a mechanistic-empirical approach, which is commonly referred to as the Mechanistic-Empirical Pavement Design Guide (MEPDG). The back calculation on the BAKFAA program was utilized to examine the existing situation. At the same time, a stress-strain analysis was performed using the KENPAVE software to calculate the response of the pavement structure. Results: The 2015 MEPDG with Arizona calibration by controlling fatigue cracking has resulted in an overlay thickness of 180 mm. In addition, the damage model was obtained for each type of road failure and can be beneficial in estimating the future IRI value. Conclusion: The damage model generated from the 2015 MEPDG procedure is specific to the types of road damage, which can eventually be utilized to predict the future IRI value. It also encompasses local and global calibration variables, such as adjustment factors for its implementation in road pavement conditions in Indonesia. The MEPDG application can be simplified by shortening the mechanistic analysis process, along with reducing traffic variations and the level of detail in the daily climate analysis.

Network formation of low molecular weight ‘liquid’ polymers studied by gel permeation chromatography and stress-strain analysis according to Mooney-Rivlin

The rheological and mechanical properties of elastomers are defined by their different networks: The crosslink network and the filler network. The crosslink network is influenced by the polymer structure. The filler network – particularly in case of silica as filler – depends on the interaction between the filler particles and the polymer. Liquid polymers can affect these networks by their lower molecular weight and with certain types by their functional groups. The goal of the present work is to gain a better understanding of the network formation: 1. During the sulfur curing of pure liquid polybutadienes with different concentrations of sulfur and curatives, and 2. Through differently added liquid polymer-silica-masterbatches in sulfur cured silica/SSBR mixtures. For the first point, the pre-cured liquid polymer samples were analyzed by gel permeation chromatography. The results indicate an association between weight concentration and the polymer chain length. For the second point, stress-strain analysis according to Mooney-Rivlin provides information about the interaction of liquid polymers with silica and the main polymer when it is added differently throughout the masterbatch approach.

The stress-strain state assessment of the heat exchange unit damper of the air handling aircraft primary system

The work solves the problem of the stress-strain state estimation of the heat exchange unit damper of the primary air handling system in modern transport aircraft, which is located in the air preparation system. It’s designed for air sampling from the engine's cruise unit or auxiliary power unit, its further processing and transportation to the life support system. When analyzing the stress-strain state of real aircraft structures, taking into account boundary conditions and load modes, analytical calculation methods are not always effective , therefore, numerical research methods were used in this work.Based on the finite element method, the stress-strain state analysis of the heat exchange unit damper was carried out, taking into account all the design features. Three-dimensional finite elements were used, which most accurately correspond to the calculation scheme. Numerical analysis of the stress-strain state made it possible to determine dangerous areas of stress where fatigue cracks may appear and destruction may be occur.

Stress–Strain Investigation of the Rock Mass Based on Overcoring with CSIRO HI Cell Test and Numerical Modeling: A Case Study from an Italian Underground Marble Quarry

The present research illustrates the application of a methodological approach to studying the stress–strain distribution in a marble quarry of the Apuan Alps mining area (Italy). This study has been carried out in the framework of a project involving the University of Siena and the UOC Ingegneria Mineraria—USL Toscana Nord-Ovest, Tuscany Region. This stress–strain analysis aims foremost to monitor the slope stability conditions to guarantee a safe workplace for the personnel involved in mining activities, and to enable more sustainable long-term planning for excavation and production. The involved survey activities are as follows: (i) terrestrial laser scanning; (ii) engineering–geological data mapping; and (iii) in situ marble stress measuring through four CSIRO-type cell tests executed in different locations and at various depths within the underground excavation walls. The gathered data converged into numerical models of the quarry, both in 2D (DEM) and 3D (FEM), calibrated by in situ stress results through a rigorous back analysis assessment using least squares procedures. The created models represent a valuable tool for the identification and securing of risk areas and for future excavation planning in respect of the site efficiency and safety.

Evaluation of stress and strain on mandible caused using “All-on-Four” system from PEEK in hybrid prosthesis: finite-element analysis

Hybrid prostheses have recently been used as suitable treatment alternatives for edentulous individuals to restore the mastication mechanism. These prostheses utilize “All on four” concept, in which four implants are inserted into the jaw bone, and supported by a bar. Titanium is usually used in the fabrication of “All on four” parts due to its good mechanical properties. However, it has many drawbacks including esthetic impairment, casting issues, hypersensitivity reactions, stress shielding, and incompatibility with imaging techniques. These drawbacks have prompted researchers to find alternative materials (e.g., polymers). Recently, the new polymeric material PEEK has a major role in dentistry, due to its biocompatibility, shock-absorbing ability, and good mechanical properties. This work used the finite-element method to conduct stress–strain analysis on mandible rehabilitated with a hybrid prosthesis, using PEEK in the fabrication of “All on four” parts instead of titanium, using different densities of spongy bone. As the density of spongy bone is expected to influence the choice of “All on four” fabrication material. A 300 N vertical force was applied unilaterally, bilaterally, and anteriorly to stimulate the different mastication mechanisms. The results illustrated that PEEK material reduced the stresses and strains on bone tissues and increased the mucosal stress, compared to titanium. Consequently, this material was recommended to be used in the fabrication of “All on four” parts, especially in the low-density model. However, further research on PEEK implants and abutments is required in near future.

Temporary sound barrier system from natural fiber polymeric composite

Sound barriers, rather than shutting off the source of noise, are the most effective method for reducing noise pollution and reducing the intensity from diverse sources. In the present study, a natural fiber was employed alongside a polymer material to produce a sound barrier system. The natural fiber composite used was Rice Husk-PU reinforced composite. The harmonic analysis was performed through ANSYS to evaluate the sound absorbing coefficient and transmission loss. More so, the stress–strain analysis with the total deformation of the panel has been analyzed. In order to have better understanding of the sound absorption coefficient and transmission loss, the frequency range on the simulation was set between 0 and 4000 Hz. The result showed better sound absorption coefficient on the lower frequency region when compared with standard and measured results from published paper. It also simulated higher transmission loss at a high frequency region since high frequency means high sound intensity level. For the validation of the simulated results, the data were compared with the tested experimental results for the same material and a very small difference was observed.

Constitutive behaviour of masonry prisms using a full-field measurement technique

To obtain analytical models for the compressive behaviour of masonry structures, it is crucial to accurately measure the compressive strengths of its constituents, i.e., brick and mortar. The mechanical properties and the stress-strain relationship under uniaxial compression are essential for thoroughly investigating and evaluating masonry structures. The present work aims to validate a non-contact measuring technique for obtaining full-scale strain and failure patterns and investigate joint mortar composition's effect on masonry behaviour. Forty masonry prisms were manufactured in this study using two distinct types of brick and five different types of mortar varying according to cement and lime contents. The results showed that 2D Digital Image Correlation (DIC) could generate full-strain assessments of masonry prisms, resulting in a full-scale stress-strain analysis. It was also found that, in the post-peak region, prisms with lower cement content exhibit a more ductile behaviour with strain localisation at the joint mortar level. Based on current experimental results and data from the literature, new analytical relationships were presented to predict masonry mechanical properties and masonry complete stress-strain compressive behaviour.

A Numerical Study on an Oscillating Water Column Wave Energy Converter with Hyper-Elastic Material

A model different from the traditional WEC, known as the flexible wave energy converter (fWEC), is numerically modeled in this paper. The fWEC is believed to be more efficient and has a greater range of operation when compared with the conventionally rigid WEC. A fully coupled fluid–structure interaction (FSI) tool is developed for the research performed in this paper. This tool is able to accommodate the dynamic interaction between the flexible membrane structure of the fWEC and the surrounding fluid. In this research, both linear-elastic and hyper-elastic materials are examined for their use in the fWEC. The fluid flow surrounding the fWEC is solved by a computational fluid dynamics (CFD) method. The deformation of the hyper-elastic structure within the fWEC is modeled using a finite element analysis method (FEA). Both the hyper-elastic material of the fWEC and the free surface wave contribute to the overall nonlinearity of the numerical simulation. To tackle this problem, a robust coupling scheme is implemented by an advanced coupling library. With this tool, the flexible deformations within the fWEC structure can be accurately captured. The degree of these deformations can then further be examined, allowing the overall effects on the fWEC energy output to be determined. The simulation results show that the peak deformation of the hyper-elastic material is four times that of the linear-elastic material. This suggests that the fWEC would perform better and generate greater power using the hyper-elastic material compared with the linear-elastic material. Additionally, because a wide range of wave conditions are studied, it can be concluded that unlike conventional WECs, the efficiency of energy harvesting of such an fWEC is not sensitive to certain wave periods. Such findings are supported by both the detailed flow fields captured and the structural stress–strain analysis results from this simulation.

Stress-strain analysis and safety evaluation of concrete-faced rockfill dams

For concrete-faced rockfill dams with a medium dam height of a pumped storage power station, the gravel overburden of the dam site will be deep and the bedrock of the riverbed will be inclined downstream. Under complex topographic and geological conditions, the deformation control of the dam and the stability of the dam slope will be very important to the safe operation of the dam. Therefore, based on the Tsinghua nonlinear decoupled K-G model of rockfill materials, in this work, we adopted the finite element method for simulating and calculating the stress and deformation characteristics of typical dam sections in the construction and storage periods, and we carried out parameter sensitivity and comparative analyses with the Shen Zhujiang double yield surface and Duncan Chang E-B models. According to the findings, the distribution of stress and deformation of the dam were reasonable and conformed to the distribution law of a rockfill dam built on a slope. The maximum horizontal displacement occurred in the middle of the compressible layer near the downstream, the maximum settlement occurred in the middle of the compressible layer, and the maximum value of the panel deflection occurred at about 1/2 of the dam height. In addition, the dam material modulus exerted little impact on the dam stress but had an obvious effect on the deformation of the dam body and face plate. The stress values of the dam body calculated by the different constitutive models showed little difference. Although the distribution law of displacement was almost the same, the magnitude difference was large. Our research results may serve to be a reference for the stress and deformation analysis and engineering design of concrete-faced rockfill dams.

Stress-strain behavior of ECC-GFRP spiral confined concrete cylinders

This paper introduces a new confinement system that combines engineered cementitious composites (ECC) with glass fiber-reinforced polymer (GFRP) spiral as a protective cover to confine the concrete core. Meanwhile, the precast ECC-GFRP spiral cover also can serve as permanent formwork to improve construction efficiency and save construction costs. This study analyzed the confinement mechanism from the combination of ECC and GFRP spiral, and the effects of concrete strength and confinement stiffness on the stress-strain behavior of the confined concrete were investigated. The stress-strain behavior analyses confirm that the residual confining stress from ECC could enhance the ductility of the composite cylinder after GFRP rupture. Test results also indicate that an ECC-GFRP spiral layer has excellent crack control capability before peak loads, guaranteeing concrete cylinder durability. In addition, the model evaluation indicates that ultimate condition models for FRP-confined concrete are also applicable to ECC-GFRP spiral-confined concrete as long as the confining pressure from both ECC and GFRP spiral can be accurately predicted. A modified stress-strain model is proposed for this confinement form and performs well against test stress-strain curves.

Examining solid-state sintering of AlCoCrFeNi multi-principal element alloy by molecular simulations

With the emergence of solid-state sintering techniques for metal additive manufacturing of multicomponent alloys, understanding the fundamental sintering mechanisms is vital for effective process control. Here, we employ molecular dynamics simulations to investigate the mechanisms involved during solid-state sintering of AlCoCrFeNi multi-principal element alloy. Our results reveal that the cross migration of atoms between the surface of powder particles promotes neck growth while minimizing the surface free energy. This phenomenon is mediated by a transition from BCC to amorphous phase resembling a pre-melt and assisting in the densification as a function of temperature. Stress–strain analysis on the alloy single crystal at room temperature suggests that permanent plastic deformation occurs with a gradual phase change to FCC predicting a tensile strength of ∼ 1547 MPa at the onset of yield and a peak stress of 2267 MPa.

Вязко-пластическое растяжение отверстия при отбортовке нагретого листа

Correlations for stress-strain analysis for the cases of the hole extension in flanging when heated are recommended. The state of visco-plasticity of an anisotropic material, is approved in principle. Trim equations and yield conditions are used in the plane stress state sketch. Correlations for the work material continuity are obtained. The results of calculations are given.

Fatigue Reliability Analysis System for Key Components of Aero-Engine

Aero-engine is known as the heart of an aircraft. Fatigue is one of the main causes of aero-engine failure, therefore, it is essential to predict the fatigue life in the aero-engine design process. Due to the uncertainty of influencing factors, it is necessary to further analyze the fatigue reliability. First, the fatigue life should be predicted on the basic of finite element analysis. The steps include parametric modeling, stress-strain analysis, load spectrum acquisition, and selection of fatigue life prediction model. Then, the reliability estimation of fatigue life should be employed, including the statistical analysis of influencing factors, reliability analysis method, and reliability estimation of fatigue life. Taking turbine blade and test probe of aero-engine as the research objects, the fatigue reliability analysis system is developed based on the ABAQUS-MATLAB platform. Statistical analysis shows that fatigue life approximately obeys lognormal distribution, and the distribution parameters estimated by MCS and Kriging are coincide, while Kriging only needs dozens of training samples. Under different reliability indexes, the design fatigue life error between Kriging and MCS is less than 1%, which meets the accuracy requirements and can effectively guide the fault detection and maintenance of aero-engine.