scholarly journals Static Analysis of a Tire Sidewall Developed From Tailored Organomodified Kaolin/Natural Rubber Vulcanizates

2017 ◽  
Vol 1 (2) ◽  
pp. 106
Author(s):  
Chinedum Ogonna Mgbemena ◽  
ThankGod Enatimi Boye ◽  
Ikuobase Emovon
Keyword(s):  
Tensile Stress ◽  
Natural Rubber ◽  
Principal Stress ◽  
Compressive Stress ◽  
Filler Loading ◽  
Elastic Behavior ◽  
Shear Stresses ◽  
Fe Model ◽  
Creative Commons ◽  
Automobile Tire

This paper is on the prediction of stress limits and strain distributions of an automobile tire sidewall developed from Natural Rubber (NR)/Tea Seed Oil (TSO) modified kaolin composites. The stress-strain data report of NR/TSO modified kaolin at filler loading of 10phr was used to establish parameters characterizing the elastic behavior of the rubber vulcanizates. The tire model investigated was developed from MATLAB PDE Toolbox. The study was developed on maximum inflation pressure of 0.220632 MPa. The 2D Finite Element (FE) model computations for static loading of the tire sidewall gave a reasonable prediction of the stress limits and strain distributions, as the shear stresses obtained were within the range of −10 MPa to 10 MPa. The strain energy distributions were found to be within the range of −1500 J·m−3 to 1500 J·m−3. The stress limits for the first principal stress with respect to their magnitudes and orientations was obtained as 10 MPa for tensile stress and −20 MPa for compressive stress respectively while the stress limits for the second principal stress was obtained as 20 MPa for tensile stress and −10 MPa for compressive stress. The plane stress analysis with MATLAB PDE Toolbox gave stress limits distribution in terms of von-Mises stresses in the range 5 MPa - 25 MPa. The results indicate that NR/TSO modified kaolin composites can be employed in automobile tire sidewall applications.  This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Shear Stress Measurements at a Dental Porcelain-Gold Bond Interface

1972 ◽  
Vol 51 (2) ◽  
pp. 626-633 ◽  
Author(s):  
Joseph J. Tuccillo ◽  
John P. Nielsen
Keyword(s):  
Shear Stress ◽  
Tensile Stress ◽  
Compressive Stress ◽  
Interfacial Shear ◽  
Shear Stresses ◽  
Interfacial Stresses ◽  
Dental Porcelain ◽  
Stress Measurements ◽  
Dental Restorations ◽  
Bond Interface

In this study a method of measuring interfacial shear stresses from the curvatures of bimaterial dental porcelain-gold strips is described. Stresses were calculated for different porcelain thicknesses and as a function of temperature. The interfacial stresses found ranged from 1,000 psi tensile stress to 3,000 psi compressive stress on the porcelain side of the interface for porcelain thicknesses commonly used in dental restorations.

Residual Stress Mapping in Railway Rails

2005 ◽  
Vol 490-491 ◽  
pp. 165-170 ◽  
Author(s):  
Joe F. Kelleher ◽  
David J. Buttle ◽  
Paul M. Mummery ◽  
Philip J. Withers
Keyword(s):  
Residual Stress ◽  
Tensile Stress ◽  
Compressive Stress ◽  
Magnetic Permeability ◽  
Shear Stresses ◽  
Plane Shear ◽  
X Ray ◽  
Heat Treated ◽  
Stress Mapping ◽  
Surface Compression

Residual stress has been mapped in the heads of three normal grade and one heat treated (350HT) ex-service railway rails. Transverse, vertical and in-plane shear stresses were deduced using energy dispersive synchrotron X-ray, magnetic permeability and laboratory X-ray measurements. Differences were found between samples both in the distribution of compressive stress introduced at the running surface, and in the locations of the balancing tensile stress below this. The heat treated rail was found to have a thinner layer of surface compression than the normal grade rails, with tensile stress being closer to the active gauge corner. The thinner layer of surface compression in the heat treated rail may reduce the protective benefits for rail integrity that surface compression is thought to confer.

Study of Pre-Stress Effect of Ribcage Structure on Chest Response of Crash Dummy Model

2010 ◽  
Author(s):  
Xinghua Lai ◽  
Qing Zhou
Keyword(s):  
Stress State ◽  
Tensile Stress ◽  
Compressive Stress ◽  
Fe Model ◽  
Stress Effect ◽  
Stress Model ◽  
Test Results ◽  
Hybrid Iii ◽  
Structural Responses ◽  
Stress States

Assembling induced pre-stress state commonly exists in the ribcage structure of Hybrid III dummy hardware. In the practice of dummy modeling, however, the pre-stress issue is often neglected. This study is intended to assess the pre-stress effect on chest response of the Hybrid III 50th percentile male dummy model. In this paper, how the pre-stress state is generated in the dummy ribcage assembling process is first elaborated by disassembling and reverse engineering a physical dummy chest structure. A thorax FE model is then built and validated against test results. Using finite element modeling approach, the structural responses with and without the pre-stress state are compared and analyzed at single rib, ribcage and full dummy levels and under a number of loading conditions. The study has found out that, there are two common pre-stress states existing in the rib components of the dummy ribcage, pre-compressive stress and pre-tensile stress. Compared with no pre-stress model, the pre-compressive stress makes a rib stiffer and the pre-tensile stress makes a rib less stiff. It is further concluded that, the pre-stress effect is significant at the single rib level and insignificant at the ribcage level and the full dummy level. This is mainly because the effects of the pre-compressive stress and the pre-tensile stress existing in the six ribs are compensated each other in the assembled ribcage. Therefore, neglecting the pre-stress effect of the ribcage structure in the dummy models is reasonable.

scholarly journals Stress–strain relationship model of glulam bamboo under axial loading

2020 ◽  
Vol 29 ◽  
pp. 2633366X2095872
Author(s):  
Yang Wei ◽  
Mengqian Zhou ◽  
Kunpeng Zhao ◽  
Kang Zhao ◽  
Guofen Li
Keyword(s):  
Tensile Stress ◽  
Compressive Stress ◽  
Failure Modes ◽  
Axial Loading ◽  
Tensile Failure ◽  
Stress Strain ◽  
Laminated Bamboo ◽  
Bamboo Scrimber ◽  
Strain Relationship ◽  
Strain Model

Glulam bamboo has been preliminarily explored for use as a structural building material, and its stress–strain model under axial loading has a fundamental role in the analysis of bamboo components. To study the tension and compression behaviour of glulam bamboo, the bamboo scrimber and laminated bamboo as two kinds of typical glulam bamboo materials were tested under axial loading. Their mechanical behaviour and failure modes were investigated. The results showed that the bamboo scrimber and laminated bamboo have similar failure modes. For tensile failure, bamboo fibres were ruptured with sawtooth failure surfaces shown as brittle failure; for compression failure, the two modes of compression are buckling and compression shear failure. The stress–strain relationship curves of the bamboo scrimber and laminated bamboo are also similar. The tensile stress–strain curves showed a linear relationship, and the compressive stress–strain curves can be divided into three stages: elastic, elastoplastic and post-yield. Based on the test results, the stress–strain model was proposed for glulam bamboo, in which a linear equation was used to describe the tensile stress–strain relationship and the Richard–Abbott model was employed to model the compressive stress–strain relationship. A comparison with the experimental results shows that the predicted results are in good agreement with the experimental curves.

Compressive Deformation and Energy Absorption Characteristics of Conductive Carbon Black Reinforced Microcellular EPDM Vulcanizates

2005 ◽  
Vol 24 (4) ◽  
pp. 209-222 ◽  
Author(s):  
S.P. Mahapatra ◽  
D.K. Tripathy
Keyword(s):  
Carbon Black ◽  
Compressive Stress ◽  
Energy Absorption ◽  
Filler Loading ◽  
Maximum Efficiency ◽  
Stress Strain ◽  
Blowing Agent ◽  
Compression Set ◽  
Rate Dependent ◽  
Conductive Carbon Black

Compressive stress-strain properties of unfilled and conductive carbon black (VulcanXC 72) filled oil extended EPDM (keltan 7341A) microcellular vulcanizates were studied as a function of blowing agent (density) and filler loading. With decrease in density, the compressive stress-strain curves for microcellular vulcanizates behaved differently from those of solid vulcanizates. The compressive stress-strain properties were found to be strain rate dependent. The log-log plots of relative density of the microcellular vulcanizates showed a fairly linear correlation with the relative modulus. The compression set at a constant stress increased with decrease in density. The efficiency of energy absorption E, was also studied as a function of filler and blowing agent loading. From the compressive stress-strain plots the efficiency E and the ideality parameter I, were evaluated. These parameters were plotted against stress to obtain maximum efficiency and the maximum ideality region, which will make these materials suitable for cushioning and packaging applications in electronic devices.

Effect of Segmented Electrodes on Piezo-Elastic and Piezo-Aero-Elastic Responses of Generator Plates

2009 ◽  
Author(s):  
Carlos De Marqui ◽  
Alper Erturk ◽  
Daniel J. Inman
Keyword(s):  
Electrical Power ◽  
Elastic Behavior ◽  
Elastic Model ◽  
Fe Model ◽  
Aeroelastic Response ◽  
Aerodynamic Model ◽  
Frequency Excitation ◽  
Elastic Responses ◽  
Electrical Power Output ◽  
Tip Mass

In this paper, the use of segmented electrodes is investigated to avoid cancellation of the electrical outputs of the torsional modes in energy harvesting from piezo-elastic and piezo-aero-elastic systems. The piezo-elastic behavior of a cantilevered plate with an asymmetric tip mass under base excitation is investigated using an electromechanically coupled finite element (FE) model. Electromechanical frequency response functions (FRFs) are obtained using the coupled FE model both for the continuous and segmented electrodes configurations. When segmented electrodes are considered torsional modes also become significant in the resulting electrical FRFs, improving broadband (or varying-frequency excitation) performance of the generator plate. The FE model is also combined with an unsteady aerodynamic model to obtain the piezo-aero-elastic model. The use of segmented electrodes to improve the electrical power generation from aeroelastic vibrations of plate-like wings is investigated. Although the main goal here is to obtain the maximum electrical power output for each airflow speed (both for the continuous and segmented electrode cases), piezoelectric shunt damping effect on the aeroelastic response of the generator wing is also investigated.

scholarly journals Long-Term Behaviour of Precast Concrete Deck Using Longitudinal Prestressed Tendons in Composite I-Girder Bridges

2018 ◽  
Vol 8 (12) ◽  
pp. 2598 ◽  
Author(s):  
Haiying Ma ◽  
Xuefei Shi ◽  
Yin Zhang
Keyword(s):  
Tensile Stress ◽  
Compressive Stress ◽  
Precast Concrete ◽  
Concrete Strength ◽  
Steel Girders ◽  
Concrete Creep ◽  
Compressive Stresses ◽  
Girder Bridge ◽  
Concrete Deck

Twin-I girder bridge systems composite with precast concrete deck have advantages including construction simplification and improved concrete strength compared with traditional multi-I girder bridge systems with cast-in-place concrete deck. But the cracking is still a big issue at interior support for continuous span bridges using twin-I girders. To reduce cracks occurrence in the hogging regions subject to negative moments and to guarantee the durability of bridges, the most essential way is to reduce the tensile stress of concrete deck within the hogging regions. In this paper, the prestressed tendons are arranged to prestress the precast concrete deck before it is connected with the steel girders. In this way, the initial compressive stress induced by the prestressed tendons in the concrete deck within the hogging region is much higher than that in regular concrete deck without prestressed tendons. A finite element analysis is developed to study the long-term behaviour of prestressed concrete deck for a twin-I girder bridge. The results show that the prestressed tendons induce large compressive stresses in the concrete deck but the compressive stresses are reduced due to concrete creep. The final compressive stresses in the concrete deck are about half of the initial compressive stresses. Additionally, parametric study is conducted to find the effect to the long-term behaviour of concrete deck including girder depth, deck size, prestressing stress and additional imposed load. The results show that the prestressing compressive stress in precast concrete deck is transferred to steel girders due to concrete creep. The prestressed forces transfer between the concrete deck and steel girder cause the loss of compressive stresses in precast concrete deck. The prestressed tendons can introduce some compressive stress in the concrete deck to overcome the tensile stress induced by the live load but the force transfer due to concrete creep needs be considered. The concrete creep makes the compressive stress loss and the force redistribution in the hogging regions, which should be considered in the design the twin-I girder bridge composite with prestressed precast concrete deck.

Stress Analysis and Microstructure Evolution of Titanium Alloy Pipe during Flattening Processing

2019 ◽  
Vol 944 ◽  
pp. 1088-1093
Author(s):  
Jun Chen ◽  
She Wei Xin ◽  
Wei Zhou ◽  
Qian Li ◽  
Si Yuan Zhang ◽  
...  
Keyword(s):  
Titanium Alloy ◽  
Tensile Stress ◽  
Compressive Stress ◽  
Outer Layer ◽  
Contact Stage ◽  
Straight Wall ◽  
Vertical Part ◽  
Left And Right ◽  
Titanium Alloy Tube ◽  
Flattening Process

TA24 titanium alloy pipe with 638mm diameter and 19mm wall thickness is carried out continuous load flatten test, and the stress of internal and external pipe wall during flatten process is studied in this paper. The results show that the TA24 titanium alloy tube has good flattening performance, and the flattening process has experienced original stage, flattened oblate stage, flattened straight wall stage, flattened depressed stage, flattened concave contact stage. During the flattening process, the outer layer of the upper and lower wall of the tube is subjected to compressive stress, and the inner layer material is subjected to tensile stress. The tensile and compressive forces cause the vertical part of the upper and lower walls to be concave. The outer layer of the left and right circular arc parts is subjected to tensile stress and the inner layer is subjected to tensile stress. The compressive stress also causes the radius of the arc to decrease due to the combined force of the tensile and compressive forces, that is, the flattening occurs. With the decrease of and pressing distance under continuous loading condition, the metal on the left and right sides of the pipe gathers toward the middle depression, which aggravates the deformation of the upper and lower walls until the upper and lower walls contact, and the arc radius of the left and right walls decreases until the outer surface cracks. The pipe microstructure changes significantly into elongated deformation structure during the flattening process. The most severe part of the deformation is the left and right end arc of the pipe, followed by the upper and lower end depression.

Effect of Vulcanization Temperature and Different Fillers on the Properties of Efficiently Vulcanized Natural Rubber

1979 ◽  
Vol 52 (2) ◽  
pp. 263-277 ◽  
Author(s):  
R. Mukhopadyay ◽  
S. K. De
Keyword(s):  
Particle Size ◽  
Natural Rubber ◽  
Crosslinking Density ◽  
Filler Loading ◽  
Zinc Stearate ◽  
Curing Temperature ◽  
Abnormal Behavior ◽  
Elongation At Break ◽  
Polymer Filler ◽  
Reinforcing Fillers

Abstract The present work deals with effect of vulcanization temperature on the polymer-filler interaction parameter, vulcanizate structure, and the technical properties of efficiently vulcanized natural rubber stocks in the presence of different fillers. We have used carbon blacks of four different particle sizes (ISAF, HAF, SRF, FT), reinforcing silica, and whiting. In the case of black fillers, as the particle size increases, reversion resistance increases. For all fillers, an increase of curing temperature from 150 to 180°C caused a reduction in strength, modulus, hardness, resilience; and an increase in elongation at break, compression set, and heat build-up. However, the flexing properties and abrasion loss showed improvement at higher curing temperature. Kraus' plots indicate that increase of curing temperature caused reduction in polymer-filler attachment. At both curing temperatures, the activity of fillers follow the order, ISAF > HAF > SRF > FT. Silica showed erratic behavior in that Kraus plots indicate nonreinforcement by the filler. Whiting also behaved abnormally with respect to Kraus plots; at lower filler loading, the system is nonadherent, becoming weakly adherent at higher concentrations. The abnormal behavior of silica-filled compounds has been explained on the basis of a reaction on the silica surface between silanol groups and zinc stearate. Westlinning and Wolff's αF values were found to be independent of curing temperature and characteristic of fillers only (the larger the particle size, the lower is the αF value). The increase in apparent crosslinking density in the case of reinforcing fillers is due to increased υr arising out of increased polymer-filler interaction. Therefore, the sulfur inefficiency parameters (E values) and zinc sulfide efficiency parameters (F values) become less significant in filled vulcanizates.

An approach to reduce stress and defects: a hybrid process of laser cladding deposition and shot peening

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Xiaoyu Zhang ◽  
Dichen Li ◽  
Jiale Geng
Keyword(s):  
Tensile Stress ◽  
Compressive Stress ◽  
Laser Cladding ◽  
Shot Peening ◽  
Hybrid Process ◽  
Layer By Layer ◽  
Residual Tensile Stress ◽  
Forming Process ◽  
Content Type ◽  
Thermal Forming

Purpose Laser cladding deposition is limited in industrial application by the micro-defects and residual tensile stress for the thermal forming process, leading to lower fatigue strength compared with that of the forging. The purpose of this paper is to develop an approach to reduce stress and defects. Design/methodology/approach A hybrid process of laser cladding deposition and shot peening is presented to transform surface strengthening technology to the overall strengthening technology through layer-by-layer forming and achieve enhancement. Findings The results show that the surface stress of the sample formed by the hybrid process changed from tensile stress to compressive stress, and the surface compressive stress introduced could reach more than four times the surface tensile stress of the laser cladding sample. At the same time, internal micro-defects such as pores were reduced. The porosity of the sample formed by the hybrid process was reduced by 90.12% than that of the laser cladding sample, and the surface roughness was reduced by 43.16%. Originality/value The authors believe that the hybrid process proposed in this paper can significantly expand the potential application of laser cladding deposition by solving its limitations, promoting its efficiency and applicability in practical cases.

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