International Journal of Mechanical and Materials Engineering最新文献

{"title":"Cross bore geometry configuration effects on stress concentration in high-pressure vessels: a review","authors":"P. K. Nziu,&nbsp;L. M. Masu","doi":"10.1186/s40712-019-0101-x","DOIUrl":"https://doi.org/10.1186/s40712-019-0101-x","url":null,"abstract":"<p>The aim of this study was to establish the effect of cross bore configuration geometry on stress concentration in cross-bored high-pressure vessels. The cross bore geometry parameters with adverse effects on stress concentration include cross bore size, shape, location, obliquity, and thickness ratio. However, there were no conducted studies on the optimal combination on these geometric configuration parameters that give minimum stress concentration, although the cited phenomena are common in pressure vessel design. Therefore, there is need for further research on the optimal geometric configuration in a high-pressure vessel under elastic, elastoplastic, and plastic operating conditions with regards to the selected cross bore configuration parameters. Optimization of the stress concentration factor will greatly improve the design of high-pressure vessels.</p>","PeriodicalId":592,"journal":{"name":"International Journal of Mechanical and Materials Engineering","volume":"14 1","pages":""},"PeriodicalIF":3.1,"publicationDate":"2019-05-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1186/s40712-019-0101-x","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"5093642","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Preparation of a high surface area zirconium oxide for fuel cell application","authors":"Rudzani Sigwadi,&nbsp;Mokhotjwa Dhlamini,&nbsp;Touhami Mokrani,&nbsp;Fulufhelo Nemavhola","doi":"10.1186/s40712-019-0102-9","DOIUrl":"https://doi.org/10.1186/s40712-019-0102-9","url":null,"abstract":"<p>Stable and high surface area zirconium oxide nanoparticles have been synthesised by means of the hydrothermal method. The Brunauer–Emmett–Teller results show that a high surface area of 543?m²/g was obtained in the hydrothermal process, having a high porosity in nanometre range. The hydrothermal method was applied at 120?°C by using an autoclave with a Teflon liner at an ambient pressure for 48?h. High-resolution scanning electron microscopy shows the different morphologies of zirconia nanoparticles, which could be categorised as one-dimensional and zero-dimensional, as they had a high crystallite orientation, which was also confirmed by the X-ray diffraction (XRD). The mixture of two types of cubic phases in one sample was obtained from XRD and confirmed by the zirconia nanostructure, showing the stable phase of fluorite, which has full cubic symmetry (<i>Im-</i>3<i>m</i>), and also an Arkelite zirconia nanostructure, showing the stable phase of fluorite, which has full cubic symmetry (<i>Fm-</i>3<i>m</i>). The XRD results also show the different structure orientations of face-centred cubic and body-centred cubic in one sample.</p>","PeriodicalId":592,"journal":{"name":"International Journal of Mechanical and Materials Engineering","volume":"14 1","pages":""},"PeriodicalIF":3.1,"publicationDate":"2019-05-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1186/s40712-019-0102-9","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4874742","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Cross bore size and wall thickness effects on elastic pressurised thick cylinders","authors":"P. K. Nziu,&nbsp;L. M. Masu","doi":"10.1186/s40712-019-0100-y","DOIUrl":"https://doi.org/10.1186/s40712-019-0100-y","url":null,"abstract":"<p>Three-dimensional finite element analyses were performed on closed-ended thick-walled cylinders with a radial cross bore under internal pressure. The aim of this study was to determine the behaviour of the hoop stress as well as to establish the optimal Stress Concentration Factors (SCF). Cylinders of thickness ratios of 3.0 down to 1.4 with cross bore size ratios (cross bore to main bore ratio) ranging from 0.1 to 1.0 were studied. The maximum hoop stress was found to increase with the increase in the cross bore size. Amongst the five different circular radial cross bore size ratios studied, the smallest cross bore size ratio of 0.1, gave the lowest hoop stress while the highest stress occurred with a cross bore size of 1.0. Moreover, the lowest SCF occurred in the smallest cross bore size ratio of 0.1 at a thickness ratio of 2.25 with a SCF magnitude of 2.836. This SCF magnitude indicated a reduction of pressure-carrying capacity of 64.7% in comparison to a similar plain cylinder without a cross bore.</p>","PeriodicalId":592,"journal":{"name":"International Journal of Mechanical and Materials Engineering","volume":"14 1","pages":""},"PeriodicalIF":3.1,"publicationDate":"2019-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1186/s40712-019-0100-y","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4960738","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Application of response surface methodology for prediction and modeling of surface roughness in ball end milling of OFHC copper","authors":"Asiful H. Seikh,&nbsp;Biplab Baran Mandal,&nbsp;Amit Sarkar,&nbsp;Muneer Baig,&nbsp;Nabeel Alharthi,&nbsp;Bandar Alzahrani","doi":"10.1186/s40712-019-0099-0","DOIUrl":"https://doi.org/10.1186/s40712-019-0099-0","url":null,"abstract":"<p>This study was conducted to investigate the synergistic effects of cutting parameters on surface roughness in ball end milling of oxygen-free high conductivity (OFHC) copper and to determine a statistical model that can suitably correlate the experimental results. Firstly, an experimental plan based on a full factorial rotatable central composite design with variable parameters, the cutting feed rate or feed per tooth, axial depth of cut, radial depth of cut, and the cutting speed, was developed. The range for each variable was varied through five different levels. Secondly, a mathematical model was formulated based on the response surface methodology (RSM) for roughness components (<i>R</i>_<i>a</i> and <i>R</i>_<i>z</i> micron). The predicted values from the model were found to be close to the actual experimental values. Finally, for checking the adequacy of the models, analysis of variance (ANOVA) was used to examine the dependence of the process parameters and their interactions. The developed model would assist in selecting the cutting variables for optimization of ball end milling process for a particular material. Based on the results from this study, it is concluded that the step over or radial depth of cut have a higher contribution (45.81%) and thus has a significant influence on the surface roughness of the milled OFHC copper.</p>","PeriodicalId":592,"journal":{"name":"International Journal of Mechanical and Materials Engineering","volume":"14 1","pages":""},"PeriodicalIF":3.1,"publicationDate":"2019-04-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1186/s40712-019-0099-0","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4444293","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Structural morphology and electronic conductivity of blended Nafion®-polyacrylonitrile/zirconium phosphate nanofibres","authors":"R. Sigwadi,&nbsp;M. S. Dhlamini,&nbsp;T. Mokrani,&nbsp;F. Nemavhola","doi":"10.1186/s40712-019-0098-1","DOIUrl":"https://doi.org/10.1186/s40712-019-0098-1","url":null,"abstract":"<p>This paper aimed to study the influence of zirconium phosphate (ZrP) nanoparticles on reducing the diameter of nanofibres during electrospinning. Addition of metal oxide such as zirconium phosphate decreases the diameter and smooths on the polyacrylonitrile (PAN) nanofibres as observed by the SEM techniques. Furthermore, this work investigated the effect of zirconium phosphate on the morphology and conductivity of modified PAN nanofibres under SEM, XRD and electrochemical cells. The PAN/zirconium phosphate nanofibres were obtained with the diameter ranges between 100 and 200?nm, which mean that the nanofibres morphology significantly changed with the addition of the zirconium phosphate nanoparticles. The conductivity of PAN and PAN-Nafion zirconium phosphate nanofibres was more improved when compared to that of the plain PAN nanofibres as observed under electrochemical measurements. The plain PAN nanofibres show the total degradation on thermal gravimetric analysis results when compared to the modified PAN with zirconium phosphate nanoparticles. The thermal properties and proton conductivity make the PAN/ZrP nanofibres as promising nanofillers for fuel cell electrolytes.</p>","PeriodicalId":592,"journal":{"name":"International Journal of Mechanical and Materials Engineering","volume":"14 1","pages":""},"PeriodicalIF":3.1,"publicationDate":"2019-01-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1186/s40712-019-0098-1","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4892768","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effect of cutting parameters on the dimensional accuracy and surface finish in the hard turning of MDN250 steel with cubic boron nitride tool, for developing a knowledged base expert system","authors":"Sasan Yousefi,&nbsp;Mehdi Zohoor","doi":"10.1186/s40712-018-0097-7","DOIUrl":"https://doi.org/10.1186/s40712-018-0097-7","url":null,"abstract":"<p>In the machining operations, final surface finish and dimensional accuracy are the most specified customer requirements. Hard turning machining operation using cubic boron nitride tool as an alternative of grinding process is a type of turning operation in which hardened steel are machined with the hardness greater than 45 HRc. During the hard turning operation because of the hard condition, the variations of surface finish and dimensional accuracy are completely different from that of the traditional turning operation. Thus, the variation of surface finish and dimensional accuracy under various cutting parameters has been investigated in the hard turning with cubic boron nitride tools.?The extracted knolwdge can be used for developing a knowledged base expert system. In order to have a comprehensive study, the variation of vibration, cutting forces, and tool wear has also been considered. The obtained results showed that depth of cut and spindle speed have the greatest effect on the dimensional accuracy, while feed rate is the most important factor affecting the surface roughness. The analysis of the vibration and tool wear proved that the flank wear has insignificant influence on the dimensional accuracy, whereas the vibration effect is considerable. The experimental results showed that when the feed rate is gradually increased from 0.08 to 0.32, the dimensional deviation first decreases unexpectedly until the lowest value is achieved at 0.16?mm/rev, then by further increasing the feed from 0.16 to 0.32?mm/rev, the dimensional deviation increases significantly. It was also seen that the best dimensional accuracy is achieved at the lowest level of the cutting depth, the medium level of the feed rate, and the spindle speed lower than its moderate level. The best surface roughness of 0.312?μm was obtained at 0.08?mm/rev feed rate, 0.5?mm depth of cut, 2000-rpm speed, and 1.2?mm insert nose radius, which is comparable with the surface finish obtained by the grinding operation.</p>","PeriodicalId":592,"journal":{"name":"International Journal of Mechanical and Materials Engineering","volume":"14 1","pages":""},"PeriodicalIF":3.1,"publicationDate":"2019-01-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1186/s40712-018-0097-7","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4299594","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"GA-based multi-objective optimization of active nonlinear quarter car suspension system—PID and fuzzy logic control","authors":"Mahesh P. Nagarkar,&nbsp;Yogesh J. Bhalerao,&nbsp;Gahininath J. Vikhe Patil,&nbsp;Rahul N. Zaware Patil","doi":"10.1186/s40712-018-0096-8","DOIUrl":"https://doi.org/10.1186/s40712-018-0096-8","url":null,"abstract":"<p>The primary function of a suspension system is to isolate the vehicle body from road irregularities thus providing the ride comfort and to support the vehicle and provide stability. The suspension system has to perform conflicting requirements; hence, a passive suspension system is replaced by the active suspension system which can supply force to the system. Active suspension supplies energy to respond dynamically and achieve relative motion between body and wheel and thus improves the performance of suspension system.</p><p>This study presents modelling and control optimization of a nonlinear quarter car suspension system. A mathematical model of nonlinear quarter car is developed and simulated for control and optimization in Matlab/Simulink? environment. Class C road is selected as input road condition with the vehicle traveling at 80?kmph. Active control of the suspension system is achieved using FLC and PID control actions. Instead of guessing and or trial and error method, genetic algorithm (GA)-based optimization algorithm is implemented to tune PID parameters and FLC membership functions’ range and scaling factors. The optimization function is modeled as a multi-objective problem comprising of frequency weighted RMS seat acceleration, Vibration dose value (VDV), RMS suspension space, and RMS tyre deflection. ISO 2631-1 standard is adopted to assess the ride and health criterion.</p><p>The nonlinear quarter model along with the controller is modeled and simulated and optimized in a Matlab/Simulink environment. It is observed that GA-optimized FLC gives better control as compared to PID and passive suspension system. Further simulations are validated on suspension system with seat and human model. Parameters under observation are frequency-weighted RMS head acceleration, VDV at the head, crest factor, and amplitude ratios at the head and upper torso?(AR_h and AR_ut). Simulation results are presented in time and frequency domain.</p><p>Simulation results show that GA-based FLC and PID controller gives better ride comfort and health criterion by reducing RMS head acceleration, VDV at the head, CF, and AR_h and AR_ut over passive suspension system.</p>","PeriodicalId":592,"journal":{"name":"International Journal of Mechanical and Materials Engineering","volume":"13 1","pages":""},"PeriodicalIF":3.1,"publicationDate":"2018-11-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1186/s40712-018-0096-8","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4873664","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Sintering driving force of Al2O3 powders at the initial stage of pulse electric current sintering under thermoelastic diffusion","authors":"Zhang Long,&nbsp;Zheng Heng-wei","doi":"10.1186/s40712-018-0095-9","DOIUrl":"https://doi.org/10.1186/s40712-018-0095-9","url":null,"abstract":"<p>The theoretical investigation of the rapid sintering mechanism under pulse electric current sintering has no unified understanding. Especially for non-conductive powder, since there is no current flowing directly through the powder materials, the driving force in the neck growth mechanism becomes a key problem and needs to make progress.</p><p>The sintering driving force of nonconductive Al₂O₃ powders at the initial stage of pulse electric current sintering is investigated under the thermoelastic diffusion coupling transmission with the consideration of non-Fourier and non-Fick effect.</p><p>The concentration diffusion flux, which is caused by the local concentration gradient, and the thermal diffusion flux act as additional driving forces for the surface curvature driving.</p><p>Equal-sized particles model reveals that these fluxes exert the dominant influence on sintering driving force for volume and simultaneous surface and volume diffusion mechanisms. In particular, the sintering driving force is remarkably increased at the postperiod of the initial stage of sintering.</p>","PeriodicalId":592,"journal":{"name":"International Journal of Mechanical and Materials Engineering","volume":"13 1","pages":""},"PeriodicalIF":3.1,"publicationDate":"2018-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1186/s40712-018-0095-9","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"5111140","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Stress-strain state of an elastic half-space with a cavity of arbitrary shape","authors":"E. A. Kalentev","doi":"10.1186/s40712-018-0094-x","DOIUrl":"https://doi.org/10.1186/s40712-018-0094-x","url":null,"abstract":"<p>Analytical method for studying stress concentration around arbitrary shape cavity is proposed.</p><p>The method is based on the assumption that it is possible to simulate the influence of cavity on the redistribution of internal forces by including fictitious forces in the solution. To determine the stress-strain state, additional forces acting on cavity surface are used. The magnitude of these forces is chosen on the basis of the value of stress tensor flow through the examined surfaces limiting cavity volume.</p><p>Research of stress-strain state for the most general three-dimensional case is done: an elastic half-space with a cubic shape cavity under action of a concentrated force applied to a free surface. The obtained results are comprehensively compared with the solution of a similar problem by the finite element method. Distributions of the stress tensor components in the vicinity of these cavities are constructed. The estimation of accuracy and efficiency of the proposed calculation model is made; the boundary of applicability of the proposed solution is determined.</p><p>It seems promising to use the resource of structural materials advantageously, namely, creating in the bodies of the cavity system the required shape and size, to obtain stress reduction at critical points, thereby increasing the strength of the product.</p>","PeriodicalId":592,"journal":{"name":"International Journal of Mechanical and Materials Engineering","volume":"13 1","pages":""},"PeriodicalIF":3.1,"publicationDate":"2018-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1186/s40712-018-0094-x","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4969807","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A new method to study free transverse vibration of the human lumbar spine as segmental multi-layer Timoshenko and Euler–Bernoulli beams","authors":"H. Asgharzadeh Shirazi,&nbsp;M. Fakher,&nbsp;A. Asnafi,&nbsp;S. Hosseini Hashemi","doi":"10.1186/s40712-018-0093-y","DOIUrl":"https://doi.org/10.1186/s40712-018-0093-y","url":null,"abstract":"<p>The aim of this study is to propose a method for studying the free transverse vibration of the human lumbar spine using Timoshenko and Euler–Bernoulli beam theories.</p><p>The cross section of the lumber spine is assumed to be uniform, and the material properties are different for the vertebral bodies, endplates, and intervertebral discs. To derive equations with biomedical approach, they were developed with <i>n</i> segments of the lumbar spine including vertebrae, intervertebral discs, and endplates.</p><p>Three first natural frequencies and mode shapes of system were computed and then validated with a finite element analyzer.</p><p>Due to good agreements between the results, it was concluded that the proposed method offered acceptable results; therefore, it can be applied to the entire spine from the neck region to the tailbone and pelvis ones.</p>","PeriodicalId":592,"journal":{"name":"International Journal of Mechanical and Materials Engineering","volume":"13 1","pages":""},"PeriodicalIF":3.1,"publicationDate":"2018-07-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1186/s40712-018-0093-y","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4542105","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}