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Journal of Iron and Steel Research International 2023年第3期30卷 475-486页

作者： Joong-Ki Hwang School of Mechatronics Engineering Korea University of Technology and EducationCheonan 31253Republic of Korea

The effect of the strain hardening exponent(n)of a material on the changes in shape,strain inhomogeneity,and contact pressure was investigated during wire flat rolling to understand its effect on the deformation behavior of a flat-rolled wire and to determine the optimal working conditions with *** deformation behaviors of wires with various n values were systematically compared using finite element *** shape of the deformed wire was found to depend on the n value of the *** the contact width and lateral spreading of the wire decrease with increasing n,resulting in a large reduction in area with the n *** strain homogeneity of the wire increases with the n value of the *** improvement in the strain homogeneity with the n value is attributable to two factors:a lower strain concentration in the central region and a higher overall elongation as n *** addition,the average effective strain of the wire cross section decreases with the n value of a material during wire flat *** contact pressure distribution on the surface of the wire differs significantly depending on the n *** materials with a low n value,the contact pressure exhibits a higher value at the entry and edge zones of the contact *** contrast,materials with high n values exhibit a higher contact pressure at the exit *** behavior can be explained by the strain hardening behavior of the material during wire flat rolling.

关键词： Strain hardening exponent Wire flat rolling Shape change Strain inhomogeneity contact pressure

contact pressure distribution and support angle optimization of kiln tyre

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Journal of Central South University of Technology 2006年第3期13卷 246-250页

作者：肖友刚潘迪夫雷先明 Key Laboratory of Track Traffic Safety of Ministry of Education Central South UniversityChangsha 410075China School of Traffic and Transportation Engineering Central South University Changsha 410075China Department of Mechanical and Energy Engineering Shaoyang UniversityShaoyang 422004 China

According to the shearing force character and the deformation coordination condition of shell at the station of supports, the mathematical models to calculate contact angle and contact pressure distribution between tyre and shell were set up, the formulae of bending moment and bending stress of tyre were obtained. Taking the maximum of tyre fatigue life as the optimal objective, the optimization model of tyre support angle was built. The computational results show that when tyre support angle is 30°, tyre life is far less than that when tyre support angle is optimal, which is 35.6°, and it is unsuitable to stipulate tyre support angle to be 30° in traditional design. The larger the load, the less the nominal stress amplitude increment of tyre, the more favorable the tyre fatigue life when tyre support angle is optimal.

关键词： tyre contact pressure support angle optimization

Influence of Alignment Errors on contact pressure during Straight Bevel Gear Meshing Process

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Chinese Journal of Mechanical Engineering 2015年第6期28卷 1089-1099页

作者： HAN Xinghui HUA Lin DENG Song LUO Qiuping Hubei Key Laboratory of Advanced Technology for Automotive Components School of Automotive EngineeringWuhan University of Technology

Straight bevel gears are widely applied in automotive, aerospace, chemical and many other fields as one of the most common type of gears. Currently, the researches on straight bevel gears have focused on the fields of fatigue, wear, noise and vibration, while little attention is paid to the effect of multiple alignment errors on the gear tooth wear. To study the influence of alignment errors on the gear tooth wear, a simulated model of a straight bevel gear pair is established. Then, the contact pressure on the tooth surface is analyzed under the various alignment errors according to the Archard wear relationship. The main combinations of alignment errors played vital roles on the tooth wear are investigated. The result shows that under the single alignment error, the contact pressure moves to the tooth heel and increases greatly at here when ？P=0.1 or ？G=0.1; when ？E=–0.03, the contact pressure greatly increases at the tooth heel, but it obviously increases at the tooth toe when ？E=0.03; the alignment error ？γ=1 has little effect on the contact pressure on the tooth surface. Moreover, the combination of ？P, ？G, ？E〈0 and ？γ is the most dangerous type among the multiple alignment errors. This research provides valuable guidelines for predicting the tooth wear under various alignment errors.

关键词： straight bevel gear multiple alignment errors contact pressure wear

Effect of contact pressure during Quenching on Microstructures and Mechanical Properties of Hot-stamping Parts

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Journal of Iron and Steel Research International 2015年第12期22卷 1138-1143页

作者： Zheng-wei GU Meng-meng L Guan-han LU Xin LI Hong XU State Key Laboratory of Automobile Materials Jilin University Department of Materials Science and Engineering Jilin University

An experimental apparatus with cooling system and pressure-adjustment assembly for simulating quench- ing was constructed to investigate the effect of contact pressure on the microstructures and mechanical properties of hot stamping parts. Qualitative and quantitative analyses of the microstructures of the as quenched parts were con- ducted; moreover, hardness and tensile tests were performed to measure their mechanical properties. The results in- dicated that contact pressure during quenching strongly affected the structures and performances of hot-stamping components. An excessive low contact pressure led to insufficient martensitic transformation. The critical contact pressure for complete martensitic transformation for 4.0 mm 22MnB5 steel was 0.4 MPa when the temperature of the coolant was 20 ℃. However, in consideration of the efficiency of practical production, a contact pressure higher than 1.25 MPa is recommended.

关键词： hot stamping quenching contact pressure microstructure mechanical property

Wavelet neural network applied for prognostication of contact pressure between soil and driving wheel

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Information Processing in Agriculture 2014年第1期1卷 51-56页

作者： Hamid Taghavifar Aref Mardani Department of Mechanical Engineering of Agricultural Machinery Faculty of AgricultureUrmia UniversityIran

This paper describes the measurement of contact pressure in the context of wheel–terrain interaction as affected by wheel load and tire inflation pressure when fusion of the wavelet transform with the back-propagation(BP)neural network is applied to construct the wavelet neural network contact pressure prediction *** this aim,a controlled soil bin testing facility equipped with single-wheel tester was utilized while three levels of velocity,three levels of slippage and three levels of wheel load were *** image processing technique,contact area values were determined which were subsequently used for quantification of contact *** of the different predictor models incorporated of various mother wavelets were evaluated using standard statistical evaluation *** mean square error and coefficient of determination values of 0.1382 and 0.9864 achieved by the optimal wavelet neural network are better than that of BP neural *** proposed tool typifies a high learning speed,enhanced predicting accuracy,and strong robustness.

关键词： Artificial neural network contact pressure Mexican hat wavelet Wavelet neural network Soil bin

Evaluation of contact pressure in Bending under Tension Test by a pressure Sensitive Film

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Journal of Surface Engineered Materials and Advanced Technology 2016年第4期6卷 201-214页

作者： Luis Fernando Folle Lirio Schaeffer Centro Universitário Ritter dos Reis Porto Alegre Brazil Universidade Federal do Rio Grande do Sul Porto Alegre Brazil

The contact pressure acting on the sheet/tools interface has been studied because of growing the concern about the wear of tools. Recent studies make use of numerical simulation software to evaluate and correlate this pressure with the friction and wear generated. Since there are many studies that determine the coefficient of friction in sheet metal forming by bending under tension (BUT) test, the contact pressure between the pin and the sheet was measured using a film that has the ability to record the applied pressure. The vertical force applied to pin was also measured. The results indicate that the vertical force is more accurate to set the contact pressure that using equations predetermined. It was also observed that the contact area between the sheet and the pin is always smaller than the area calculated geometrically. The friction coefficient was determined for the BUT test through several equations proposed by various authors in order to check if there is much variation between the results. It was observed that the friction coefficient showed little variation for each equation, and each one can be used. The material used was the commercially pure aluminum, alloy Al1100.

关键词： Coefficient of Friction Sheet Metal Forming Process Bending under Tension Test contact pressure Technology Applied to Design

Investigation of contact behavior on a model of the dual-mobility artificial hip joint for Asians in different inner liner thicknesses

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World Journal of Orthopedics 2024年第4期15卷 321-336页

作者： Taufiq Hidayat Muhammad Imam Ammarullah Rifky Ismail Eko Saputra M Danny Pratama Lamura Chethan K N Athanasius Priharyoto Bayuseno J Jamari Department of Mechanical Engineering Universitas Muria KudusKudus 59352Central JavaIndonesia Department of Mechanical Engineering Universitas DiponegoroSemarang 50275Central JavaIndonesia Undip Biomechanics Engineering&Research Centre Universitas DiponegoroSemarang 50275Central JavaIndonesia Center for Biomechanics Biomaterials Biomechatronics and Biosignal Processing Universitas DiponegoroSemarang 50275Central JavaIndonesia Department of Mechanical Engineering Politeknik Negeri SemarangSemarang 50275Central JavaIndonesia Department of Aeronautical and Automobile Engineering Manipal Institute of TechnologyManipalManipal Academy of Higher EducationManipal 576104KarnatakaIndia

BACKGROUND The four components that make up the current dual-mobility artificial hip joint design are the femoral head,the inner liner,the outer liner as a metal cover to prevent wear,and the acetabular *** acetabular cup and the outer liner were constructed of 316L stainless *** the same time,the inner liner was made of ultra-high-molecular-weight polyethylene(UHMWPE).As this new dual-mobility artificial hip joint has not been researched extensively,more tribological research is needed to predict *** thickness of the inner liner is a significant component to consider when calculating the contact *** To make use of finite element analysis to gain a better understanding of the contact behavior in various inner liner thicknesses on a new model of a dual-mobility artificial hip joint,with the ultimate objective of determining the inner liner thickness that was most suitable for this particular type of dual-mobility artificial hip *** In this study,the size of the femoral head was compared between two diameters(28 mm and 36 mm)and eight inner liner thicknesses ranging from 5 mm to 12 *** the finite element method,the contact parameters,including the maximum contact pressure and contact area,have been evaluated in light of the Hertzian contact *** simulation was performed statically with dissipated energy and asymmetric *** types of interaction were surface-to-surface contact and normal contact *** The maximum contact pressures in the inner liner(UHMWPE)at a head diameter of 28 mm and 36 mm are between 3.7-13.5 MPa and 2.7-10.4 MPa,*** maximum von Mises of the inner liner,outer liner,and acetabular cup are 2.4–11.4 MPa,15.7–44.3 MPa,and 3.7–12.6 MPa,respectively,for 28 mm *** the maximum von Mises stresses of the 36 mm head are 1.9-8.9 MPa for the inner liner,9.9-32.8 MPa for the outer liner,and 2.6-9.9 MPa for the acetabular cup.A head with a diameter of 28 mm should have an inner line

关键词： contact behavior contact pressure Finite element analysis Dual-mobility Artificial hip joint

Finite element analysis of tibio-femoral contact mechanics of a customised knee spacer

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Biosurface and Biotribology 2022年第2期8卷 121-128页

作者： Alex C.T.Choh Andy Yew Seng Jin Yeo Desmond Y.R.Chong Shi-Lu Chia Department of Orthopaedic Surgery Singapore General HospitalSingaporeSingapore Engineering Cluster Singapore Institute of TechnologySingaporeSingapore

With one-third of patients having osteoarthritis predominantly in one compartment of the knee,unicompartmental knee spacers have been introduced as a less invasive alternative to total knee ***,patients with the knee spacer implanted were seen to have persistent pain,resulting in high revision rates.A static finite element model of the knee and its interaction with a knee spacer implant at full extension and 90°flexion was used to investigate the tibio-femoral contact mechanics of the knee joint after a knee spacer *** different knee spacer designs(contoured,flat and C-shaped)were modelled and prescribed with cobalt-chrome,ultra-high molecular polyethylene and polyurethane material *** results suggested that a softer spacer is generally preferred as this helps in the conformity of knee spacer to the condyle,effectively distributing the load subjected to the *** spacers that result in high stresses resulting from lower contact areas should be avoided.

关键词： biomechanics contact pressure finite element analysis knee spacer

Surface contact behavior of functionally graded thermoelectric materials indented by a conducting punch

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Applied Mathematics and Mechanics(English Edition) 2021年第5期42卷 649-664页

作者： Xiaojuan TIAN Yueting ZHOU Lihua WANG Shenghu DING School of Aerospace Engineering and Applied Mechanics Tongji UniversityShanghai 200092China School of Mathematics and Statistics Ningxia UniversityYinchuan 750021China

The contact problem for thermoelectric materials with functionally graded properties is *** material properties,such as the electric conductivity,the thermal conductivity,the shear modulus,and the thermal expansion coefficient,vary in an exponential *** the Fourier transform technique,the electro-thermoelastic problems are transformed into three sets of singular integral equations which are solved numerically in terms of the unknown normal electric current density,the normal energy flux,and the contact ***,the complex homogeneous solutions of the displacement fields caused by the gradient parameters are simplified with the help of Euler’s *** addressing the non-linearity excited by thermoelectric effects,the particular solutions of the displacement fields can be *** effects of various combinations of material gradient parameters and thermoelectric loads on the contact behaviors of thermoelectric materials are *** results give a deep insight into the contact damage mechanism of functionally graded thermoelectric materials(FGTEMs).

关键词： thermoelectric material functionally graded property conducting punch conjugate complex root energy flux contact pressure

An analytical model for predicting sheet springback after V-bending

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2007年第2期8卷 237-244页

作者： ZHANG Dong-juan CUI Zhen-shan CHEN Zhi-ying RUAN Xue-yu National Mold ＆ Die CAD Engineering Research Center Shanghai Jiao Tong University Shanghai 200030 China

Springback is caused by the redistribution of stress in sheet material after the tooling is removed. Precise prediction of sheet springback is very important in die design. Based on Hill’s yielding criterion and plane strain condition, an analytical model is proposed in this paper which takes into account the effects of contact pressure, the length of bending arm between the punch and die, transverse stress, neutral surface shifting and sheet thickness thinning on the sheet springback of V-bending. The predicted results by this analytical model indicated that the contact pressure and transverse stress have much effect on the springback when the bending ratio (the ratio of punch radius to sheet thickness) is less than five. The contact pressure declined when the length of bending arm goes up, which means that shorter length of bending arm will result in larger springback. The effect of neutral surface shifting on the springback is less than that of contact pressure and decreases with the bending ratio. However, this research showed that the influence of thickness thinning on the springback can be ignored. Comparison with finite element method (FEM) simu-lating results shows that the predicted results by the analytical model accord well with simulation results by FEM. In addition to that, the bending ability—the limit bending ratio for a given sheet thickness and material properties was also determined.

关键词： Springback V-bending contact pressure Neutral surface shifting Transverse stress Bending ratio