Journal articles: 'Contact pressure'

1

Biboulet, N., A. A. Lubrecht, and L. Houpert. "Contact pressure in indented elastohydrodynamic lubrication contacts." Proceedings of the Institution of Mechanical Engineers, Part J: Journal of Engineering Tribology 222, no. 3 (March 2008): 415–21. http://dx.doi.org/10.1243/13506501jet324.

Full text

APA, Harvard, Vancouver, ISO, and other styles

2

Biwa, Shiro, Yukiko Inoue, and Nobutada Ohno. "OS02W0060 Influence of contact pressure on guided wave propagation at contact interface." Abstracts of ATEM : International Conference on Advanced Technology in Experimental Mechanics : Asian Conference on Experimental Mechanics 2003.2 (2003): _OS02W0060. http://dx.doi.org/10.1299/jsmeatem.2003.2._os02w0060.

Full text

APA, Harvard, Vancouver, ISO, and other styles

3

Greenwood, J. A. "Contact Pressure Fluctuations." Proceedings of the Institution of Mechanical Engineers, Part J: Journal of Engineering Tribology 210, no. 4 (December 1996): 281–84. http://dx.doi.org/10.1243/pime_proc_1996_210_509_02.

Full text

APA, Harvard, Vancouver, ISO, and other styles

4

Johns-Rahnejat, P. M., and R. Gohar. "Measuring contact pressure distributions under elastohydrodynamic point contacts." Tribotest 1, no. 1 (September 1994): 33–53. http://dx.doi.org/10.1002/tt.3020010103.

Full text

APA, Harvard, Vancouver, ISO, and other styles

5

Gu, Yungao, Junfeng Li, Jing Yang, Haojie Xia, and Xue Chang. "Simulation Study of AC Contactor Dynamic Contacts Contact Pressure Based on ADAMS." MATEC Web of Conferences 22 (2015): 02024. http://dx.doi.org/10.1051/matecconf/20152202024.

Full text

APA, Harvard, Vancouver, ISO, and other styles

6

Yang, Xiao Yan, You Gang Xiao, Xian Ming Lei, and Guo Xin Chen. "Contact Pressure of Loose-Fitted Tyre under Intermittent Contact." Advanced Materials Research 816-817 (September 2013): 1015–18. http://dx.doi.org/10.4028/www.scientific.net/amr.816-817.1015.

Full text

Abstract:

The total loads between kiln support are transmitted to the shell cross-section at tyre as shearing forces. According to the character and the condition of shell deformation and force balance, the mathematical models of contact pressure have been set up between tyre and shell under intermittent contact. The contact zones and contact pressures between tyre and shell are solved when the support reactions and gaps are variable. The results show the contact pressures increase with the increase of support reactions and gaps, the contact zones are proportional to support reactions, and inversely proportional to the gaps, which provide the reason for sound axis alignment and gap design.

APA, Harvard, Vancouver, ISO, and other styles

7

IMADO, Keiji, Masuji NAGATOSHI, Atsuyoshi MIURA, and Hioomi MIYAGAWA. "Calculation of contact pressure in conformal contact." Proceedings of the JSME annual meeting 2003.4 (2003): 149–50. http://dx.doi.org/10.1299/jsmemecjo.2003.4.0_149.

Full text

APA, Harvard, Vancouver, ISO, and other styles

8

Kim, Hyoungkyun, Seungmoon Choi, and Wan Kyun Chung. "Contact Force Decomposition Using Contact Pressure Distribution." IEEE Robotics and Automation Letters 2, no. 1 (January 2017): 290–97. http://dx.doi.org/10.1109/lra.2016.2598554.

Full text

APA, Harvard, Vancouver, ISO, and other styles

9

Smeeth, M., and H. A. Spikes. "Central and Minimum Elastohydrodynamic Film Thickness at High Contact Pressure." Journal of Tribology 119, no. 2 (April 1, 1997): 291–96. http://dx.doi.org/10.1115/1.2833204.

Full text

Abstract:

A new optical technique has been developed which is able to obtain accurate film thickness profiles across elastohydrodynamic (EHD) contacts. This has been used in conjunction with a high pressure EHD test rig to obtain both central and minimum EHD film thicknesses at high contact pressures up to 3.5 GPa. The results have been compared with the classical film thickness equations of Hamrock and Dowson and also with recent high pressure computations due to Venner. It is found that minimum film thickness falls more rapidly with applied load at high than at low contact pressures, with a film thickness/load exponent of −0.3. This confirms the findings of recent high pressure computational EHD modeling.

APA, Harvard, Vancouver, ISO, and other styles

10

Muratov, K. R., T. R. Ablyaz, and E. A. Gashev. "Contact Pressure in Honing." Russian Engineering Research 40, no. 10 (October 2020): 859–61. http://dx.doi.org/10.3103/s1068798x20100160.

Full text

APA, Harvard, Vancouver, ISO, and other styles

11

Bregar, Maksimilijan, Miran Bürmen, Uroš Aljancic, Blaž Cugmas, Franjo Pernuš, and Boštjan Likar. "Contact pressure–aided spectroscopy." Journal of Biomedical Optics 19, no. 2 (February 21, 2014): 020501. http://dx.doi.org/10.1117/1.jbo.19.2.020501.

Full text

APA, Harvard, Vancouver, ISO, and other styles

12

Jayawickrama, Eranga Gayanath, Hayata Tamai, Jun Muto, and Hiroyuki Nagahama. "Pressure dependence of elastic deformation at multiple contacts and estimation of contact state of thin cracks." GEOPHYSICS 84, no. 4 (July 1, 2019): WA153—WA160. http://dx.doi.org/10.1190/geo2018-0501.1.

Full text

Abstract:

The pressure dependence of elastic deformation at multiple contacts in thin cracks has been investigated through the variation of elastic wave velocity. By extending previously introduced single-contact load-displacement relationships to those of multiple contacts and obtaining the first derivative of pressure with respect to the displacement at contacts, relationships for the pressure dependence of elastic deformation are obtained. The obtained relationships indicated that the pressure dependence is given by a pressure exponent [Formula: see text], which is the multiple contact state of thin cracks. This was correlated with a similar pressure exponent in an empirically derived elastic wave velocity relationship, and we found that the contact state can be obtained by the empirical relationship. The estimated multiple contact state has two ideal values of 0.67 and 0.5 for conical and flat contacts, respectively, and [Formula: see text] values between the ideal states give the pressure dependence of elastic deformation of contacts, formed by a mixture of two ideal states and their population. The contact state values smaller than 0.5 and values greater than 0.67 indicate closed and open state of cracks, respectively. From previously published data on elastic wave velocities of various rocks, it is verified that the pressure dependence of elastic deformation of multiple contacts can be quantitatively obtained by the estimated contact states from the pressure dependence of elastic wave velocity.

APA, Harvard, Vancouver, ISO, and other styles

13

Kshirsagar,, Bapurao, Prashant Misra,, Nagaraju Jampana, and, and M. V. Krishna Murthy. "Thermal Contact Conductance Across Gold-Coated OFHC Copper Contacts in Different Media." Journal of Heat Transfer 127, no. 6 (June 1, 2005): 657–59. http://dx.doi.org/10.1115/1.1865215.

Full text

Abstract:

The thermal contact conductance studies across gold-coated oxygen-free high-conductivity copper contacts have been conducted at different contact pressures in vacuum, nitrogen, and helium environments. It is observed that the thermal contact conductance increases not only with the increase in contact pressure but also with the increase in thermal conductivity of interstitial medium. The experimental data are found to be in good agreement with the literature.

APA, Harvard, Vancouver, ISO, and other styles

14

Wang, Qian (Jane), Fanghui Shi, and Si C. Lee. "A Mixed-Lubrication Study of Journal Bearing Conformal Contacts." Journal of Tribology 119, no. 3 (July 1, 1997): 456–61. http://dx.doi.org/10.1115/1.2833519.

Full text

Abstract:

Numerical analyses of finite journal bearings operating with large eccentricity ratios were conducted to better understand the mixed lubrication phenomena in conformal contacts. The average Reynolds equation derived by Patir and Cheng was utilized in the lubrication analysis. The influence function, calculated numerically using the finite element method, was employed to compute the bearing deformation. The effects of bearing surface roughness were incorporated in the present analysis for the calculations of the asperity contact pressure and the asperity contact area. The numerical solutions of the hydrodynamic and asperity contact pressures, lubricant film thickness, and asperity contact area were evaluated based on a simulated bearing-journal geometry. The calculations revealed that the asperity contact pressure may vary significantly along both the width and the circumferential directions. It was also shown that the asperity contacts and the lubricant film thickness were strongly dependent on the bearing width, asperity orientation, and operating conditions.

APA, Harvard, Vancouver, ISO, and other styles

15

Karami, G., H. P. Evans, and R. W. Snidle. "Elastohydrodynamic Lubrication of Circumferentially Finished Rollers having Sinusoidal Roughness." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 201, no. 1 (January 1987): 29–36. http://dx.doi.org/10.1243/pime_proc_1987_201_084_02.

Full text

Abstract:

The paper describes an isothermal elastohydrodynamic lubrication analysis of rollers having circumferential sinusoidal roughness. Theoretical results are shown which demonstrate the influence of roughness amplitude on the distribution of hydrodynamic pressure and film thickness at constant load and constant roughness wavelength. At a large roughness amplitude the hydrodynamic pressure in the valleys between asperity contacts is insignificant and each asperity contact behaves as an ‘isolated’ elastohydrodynamic point contact. As the roughness is reduced, however, the valley pressures build up, the pressure becomes more uniformly distributed in the axial direction and the minimum film thickness increases.

APA, Harvard, Vancouver, ISO, and other styles

16

Özdemir, Ömer, Felix Fischer, Adrian Rienäcker, and Katharina Schmitz. "Thermo-elastohydrodynamic simulation of the piston-cylinder contact in high-pressure pumps at 3000 bar." Industrial Lubrication and Tribology 71, no. 5 (July 8, 2019): 702–5. http://dx.doi.org/10.1108/ilt-05-2018-0169.

Full text

Abstract:

Purpose The purpose of this paper is to show these effects in an abstracted micro gap test bench. Because of stronger emission laws, the ambition to raise the rail pressure in common-rail systems from the current 2500 bar to 3000 bar is a given. The pressure increase will allow fine atomization of fuel and therefore more efficient combustion. But within the technical system of the high-pressure pump, stronger thermal stresses of the piston–cylinder contact are expected. A pressure drop from such a high level causes high temperature gradients due to energy dissipation. Design/methodology/approach For a detailed examination, the critical piston–cylinder contact has been investigated in an abstracted test bench with a flat parallel gap and an equivalent thermo-elastohydrodynamic simulation model. Findings The simulation results show good accordance to the measurements of pressures, temperatures and leakages for pressures up to 3000 bar. Comparison with elastohydrodynamic lubrication results outlines the need to consider temperature and pressure effects viscosity and solid deformation for the simulation and design of tribological contacts at high pressures. Originality/value This paper describes a simulation method with high accuracy to investigate tribological contacts considering temperature effects on solid structures and the fluid film. The thermo-elastohydrodynamic lubrication simulation method is valid not only for piston–cylinder contacts in high-pressure pumps but also for journal bearings in combustion engines.

APA, Harvard, Vancouver, ISO, and other styles

17

Glovnea, Marilena, Sergiu Spinu, and Emanuel Diaconescu. "Improved Pressure Distribution in Elliptic Elastic Contacts between High-Order Surfaces." Advances in Tribology 2012 (2012): 1–11. http://dx.doi.org/10.1155/2012/832859.

Full text

Abstract:

The improvement of mechanical contacts or microcontacts seeks a nearly uniform current density over most of contact area. When microtopography is homogeneous, this aim is achieved if nominal shape of contacting surfaces yields a nearly uniform central pressure which decreases monotonously to zero in contour points. These authors derived recently this shape for circular contacts by employing high-order surfaces. This paper extends this result to elliptical contacts. Some results are used to this end, derived for elliptical elastic contacts between high-order surfaces. As homogeneous high order surfaces lead to a highly nonuniform pressure distribution, central pressure is flattened by making the first derivatives of pressure vanish in contact center. Then, the contacts between fourth, sixth, and eighth, order surfaces are analyzed and recurrence relations for pressure distribution and contact parameters are proposed.

APA, Harvard, Vancouver, ISO, and other styles

18

Tuoheti, Yilihamu, Eiji Itoi, Nobuyuki Yamamoto, Nobutoshi Seki, Hidekazu Abe, Hiroshi Minagawa, Kyoji Okada, and Yoichi Shimada. "Contact Area, Contact Pressure, and Pressure Patterns of the Tendon-Bone Interface after Rotator Cuff Repair." American Journal of Sports Medicine 33, no. 12 (December 2005): 1869–74. http://dx.doi.org/10.1177/0363546505278256.

Full text

Abstract:

Background The contact pressure and contact area at the tendon-bone interface after the most commonly used rotator cuff repair methods have not been investigated. Hypothesis There are no significant differences among the transosseous, the single-row suture anchor, and the double-row suture anchor techniques in terms of contact pressure, contact area, and pressure patterns at the tendon-bone interface. Study Design Controlled laboratory study. Methods After creating a full-thickness supraspinatus tendon tear in 10 cadaveric shoulder specimens, we inserted pressure-sensitive film between the tendon stump and the bone, and we repaired the tear by (1) transosseous, (2) single-row suture anchor, and (3) double-row suture anchor techniques. Results The contact area of the double-row technique was 42% greater than that of the transosseous technique (P <. 0001) and 60% greater than that of the single-row technique. The contact area of the transosseous technique was 31% greater than that of the single-row technique (P =. 0015). The average pressures of the single-row and double-row techniques were 18% (P =. 014) and 16% (P =. 03) greater, respectively, than that of the transosseous technique, but there was no significant difference between the single-row and double-row techniques (P =. 915). Conclusions The double-row technique produced the greatest contact area and the second-highest contact pressure, whereas the single-row technique created the highest contact pressure and the least contact area. The transosseous technique produced the second-greatest contact area and the least contact pressure. Clinical Relevance The double-row suture anchor technique and the transosseous technique may provide a better environment for tendon healing.

APA, Harvard, Vancouver, ISO, and other styles

19

Křupka, I., M. Vrbka, M. Vaverka, R. Poliščuk, and M. Hartl. "Effect of surface dents on contact pressure in elastohydrodynamic contacts." Proceedings of the Institution of Mechanical Engineers, Part J: Journal of Engineering Tribology 223, no. 4 (March 18, 2009): 683–93. http://dx.doi.org/10.1243/13506501jet572.

Full text

APA, Harvard, Vancouver, ISO, and other styles

20

Berglund, Kim, Maria Rodiouchkina, Jens Hardell, Kalle Kalliorinne, and Jens Johansson. "A Novel Reciprocating Tribometer for Friction and Wear Measurements with High Contact Pressure and Large Area Contact Configurations." Lubricants 9, no. 12 (December 17, 2021): 123. http://dx.doi.org/10.3390/lubricants9120123.

Full text

Abstract:

There are many moving machine assemblies with conformal tribological contacts at very high contact pressures, e.g., sliding bearings, propeller shaft bearings and machine guideways. Furthermore, applications such as trunnion and guide vane bearing in Kaplan turbines have very low sliding speeds and oscillatory types of motion. Although there is a vast selection of tribology test rigs available, there is still a lack of test equipment to perform friction and wear tests under high contact pressure, reciprocatory sliding and large area contact. The aim of this work is thus to develop a novel reciprocating tribometer and test method that enables friction and wear tests under low-speed reciprocatory sliding with contact pressures up to 90 MPa in a flat-on-flat contact configuration. First, a thorough description of the test rig design is given. Secondly, the influence of contact pressure and stroke length on the tribological properties of a stainless steel and polymer composite material combination is studied. The significance of considering creep, friction during the stroke and contact temperature is specifically highlighted. The novel tribometer can be used to screen different bearing and shaft material combinations and to evaluate the friction and wear performance of self-lubricating bearings for the specific operating conditions found in Kaplan turbines.

APA, Harvard, Vancouver, ISO, and other styles

21

Sun, Wei Ming, Shui Sheng Chen, and Li Qun Tu. "Effect of Contact Pressure and Cyclic Stress Amplitude on Fretting Fatigue of 45-Carbon Steel." Key Engineering Materials 353-358 (September 2007): 134–37. http://dx.doi.org/10.4028/www.scientific.net/kem.353-358.134.

Full text

Abstract:

The effect of contact pressure on fretting fatigue in quenched and tempered 45-carbon steel is studied. With an increase in contact pressure, fretting fatigue life is decreased quickly at low contact pressures; however it almost unchanged at high contact pressures. With an increase in cyclic stress amplitude, fretting fatigue life decreased. In the test, concavity is formed at the fretted area accompanying wear. The main crack is initiated at the outer edge corner of the concavity at high contact pressures, and initiated at the middle portion of the fretted area at low contact pressures.

APA, Harvard, Vancouver, ISO, and other styles

22

Herold, Bernd, Martin Geyer, and Clifford J. Studman. "Fruit contact pressure distributions — equipment." Computers and Electronics in Agriculture 32, no. 3 (October 2001): 167–79. http://dx.doi.org/10.1016/s0168-1699(01)00160-0.

Full text

APA, Harvard, Vancouver, ISO, and other styles

23

Goonetilleke, Ravindra S., and Timothy J. Eng. "Contact Area Effects on Discomfort." Proceedings of the Human Factors and Ergonomics Society Annual Meeting 38, no. 10 (October 1994): 688–90. http://dx.doi.org/10.1177/154193129403801032.

Full text

Abstract:

Most “ergonomic” products attempt to adopt a uniform force distribution strategy to improve comfort. The rationale being that force distribution over a large area reduces pressure and thereby enhances user comfort. However, sensory literature alludes to the concept of spatial summation, i.e. greater sensation by stimulating a larger surface area. Hence spatial summation would tend to suggest a greater discomfort when forces are applied over large surface areas. This study reports the effect of surface area on maximum discomfort causing pressure or maximum pressure tolerance (MPT). Two circular probes of different cross sectional area were used to stimulate the skin surface. The mean MPT with a probe of 5mm diameter was 3.3 times higher than the MPT with a probe of 13mm diameter. These findings suggest the following: • Perceived discomfort and contact area seem to have a “U-relationship” above a critical force value. Traditional thinking of distributing forces is successful only in the first half of the U-curve or with forces below the critical value. The section with the monotonically increasing relationship between discomfort and contact area (i.e., second half of U) may not be seen at very low forces or forces below the critical value. • “High” pressures in concentrated areas may cause less discomfort than “moderate” pressures over a larger area. • The critical or threshold pressure to induce discomfort is force and contact area dependent.

APA, Harvard, Vancouver, ISO, and other styles

24

Feng, Chaoqun, Pei Zhang, Chengshun Xu, and Xiuli Du. "Influence of the initial hydrostatic pressure on contact area coefficient under drainage condition." E3S Web of Conferences 276 (2021): 01023. http://dx.doi.org/10.1051/e3sconf/202127601023.

Full text

Abstract:

The expression of effective stress proposed by Terzaghi has always been questioned. Many correction formulas are modification of pore pressure term. The pore pressure factor is related to porosity, contact area and other factors. When the particles are in point contact, the expression of the effective stress is that proposed by Terzaghi, while for the surface contact particles, the actual effective stress increases the stress produced by pore pressure passing through the contact surface based on the Terzaghi effective stress. There are many factors that affect the development of contact area and pore pressure, therefore, a series of the drained triaxial tests were carried out on four groups of sand samples with different initial hydrostatic pressures to study the influence of different initial hydrostatic pressures on the effective stress due to the term of contact area (σα). The test results show that the shear strength is increases with the initial hydrostatic pressure under the same effective confining pressure, which indirectly indicates that the initial hydrostatic pressure increases the contact area stress.

APA, Harvard, Vancouver, ISO, and other styles

25

Pau, Massimiliano, Francesco Aymerich, and Francesco Ginesu. "Distribution of contact pressure in wheel–rail contact area." Wear 253, no. 1-2 (July 2002): 265–74. http://dx.doi.org/10.1016/s0043-1648(02)00112-6.

Full text

APA, Harvard, Vancouver, ISO, and other styles

26

Fang, N., L. Chang, and G. J. Johnston. "Some Insights Into Micro-EHL Pressures." Journal of Tribology 121, no. 3 (July 1, 1999): 473–80. http://dx.doi.org/10.1115/1.2834092.

Full text

Abstract:

An analytical model is developed in this paper which relates the major component of micro-EHL pressure responses to lubricant properties, roughness geometry, contact load, velocity, and slide-to-roll ratio. Analyses are then conducted showing the effects of system parameters on this micro-EHL pressure. For a Newtonian lubricant with an exponential pressure-viscosity law, this pressure would be large unless the contact practically operates right at pure rolling. The magnitude of the pressure rippling is largely independent of the slide-to-roll ratio, and smaller wavelength components of the surface roughness generate larger micro-EHL pressures. With less dramatic pressure-viscosity enhancement such as the two-slope model, the micro-EHL pressure is generally smaller and sensitive to the slide-to-roll ratio, larger with higher sliding in the contact. Furthermore, this pressure-viscosity model yields a micro-EHL pressure that becomes vanishingly small corresponding to sufficiently small wavelength components of the roughness. For a shear-thinning non-Newtonian lubricant, such as the Eyring model, with an exponential pressure-viscosity law, substantially less micro-EHL pressure rippling is generally developed than its Newtonian counterpart. While the pressure rippling is insensitive of the slide-to-roll ratio like its Newtonian counterpart, it vanishes corresponding to sufficiently small wavelength components of the roughness. The analyses revealed that a key factor resulting in a smaller micro-EHL pressure with the two-slope model or the Eyring model is the lower viscosity or shear-thinned effective viscosity in the loaded region of the contact. Since EHL traction is proportional to this viscosity, contacts lubricated with oils exhibiting higher traction behavior would develop larger micro-EHL pressures and thus would be more vulnerable to fatigue failure.

APA, Harvard, Vancouver, ISO, and other styles

27

Pereira, Michael P., Wen Yi Yan, and Bernard F. Rolfe. "Modeling of Contact Pressure in Sheet Metal Forming." Materials Science Forum 561-565 (October 2007): 1975–78. http://dx.doi.org/10.4028/www.scientific.net/msf.561-565.1975.

Full text

Abstract:

For a given sheet metal forming process, an accurate determination of the contact pressure distribution experienced is an essential step towards the estimation of tool life. This investigation utilizes finite element (FE) analysis to determine the evolution and distribution of contact pressure over the die radius, throughout the duration of a channel forming process. It was found that a typical two-peak steady-state contact pressure response exists for the majority of the process. However, this was preceded by a transient response, which produced extremely large and localized contact pressures. Notably, it was found that the peak transient contact pressure was more than double the steady-state peak. These contact pressure results may have a significant influence on the tool wear response and therefore impact current wear testing and prediction techniques. Hence, an investigation into the validity of the predicted contact pressure was conducted.

APA, Harvard, Vancouver, ISO, and other styles

28

Ju, Y., and T. N. Farris. "Spectral Analysis of Two-Dimensional Contact Problems." Journal of Tribology 118, no. 2 (April 1, 1996): 320–28. http://dx.doi.org/10.1115/1.2831303.

Full text

Abstract:

Contact problems can be converted into the spatial frequency domain using Fast Fourier Transform (FFT) techniques. Spectral analysis is used to develop an algebraic relationship between the surface displacement and the contact pressure. This relationship can be used to find the contact pressure or displacement for the contact of smooth surfaces or the complete contact of rough surfaces. In addition to providing rapid, robust solutions to contact problems, the algebraic relationship contains details of the relationship between surface displacement and contact pressure on different length scales. In particular, it is shown that the frequency composition of pressure is similar to that for slope of the surface displacement. Thus, the high frequency content of the surface profile gives rise to high localized contact pressure, in some cases singular pressure for complete contact. However, measurement limitations always lead to the omission of certain high frequency components of the surface profile. Assuming that the high frequency content of the surface profile obeys a power law, spectral analysis is also used to estimate partial contact parameters. This result relates the exponent of the power law to the contact pressure and implied surface integrity. It is concluded that spectral analysis can be combined with the FFT to provide a useful technique for classifying rough surface contacts.

APA, Harvard, Vancouver, ISO, and other styles

29

Glovnea, Marilena, and Emanuel Diaconescu. "Improvement of Punch Profiles for Elastic Circular Contacts." Journal of Tribology 128, no. 3 (March 21, 2006): 486–92. http://dx.doi.org/10.1115/1.2197522.

Full text

Abstract:

Machine design and electrical contacts involve frequently elastic circular contacts subjected to normal loads. Depending on geometry, these may be Hertzian or surface contacts. Both possess highly nonuniform pressure distributions which diminish contact load carrying capacity. The achievement of a uniform pressure distribution would be ideal to improve the situation, but this violates stress continuity. Instead, the generation of a uniform pressure over most of contact area can be sought. Generally, equivalent punch profile which generates this pressure is found by numerical evaluation of double integrals. This paper simplifies the derivation of punch profile by using an existing correspondence between a polynomial punch surface and elastically generated pressure. First, an improved pressure profile is proposed seeking to avoid high Huber-Mises-Hencky stresses near contact surface. Then, this is approximated by the product between typical Hertz square root and an even polynomial, which yields directly the punch profile. Formulas for normal approach and central pressure are derived.

APA, Harvard, Vancouver, ISO, and other styles

30

Xu, Zhi Qian, Xiang Zhen Yan, and Xiu Juan Yang. "Contact Mechanics Analysis of Two Rough Surfaces in Contact." Advanced Materials Research 154-155 (October 2010): 531–34. http://dx.doi.org/10.4028/www.scientific.net/amr.154-155.531.

Full text

Abstract:

In this paper, the calculation formulas of the asperity’s deformation related with the surface contact pressure are deduced by using the simplified contact model. Firstly, we assume that the rough surface is composed of a set of cones as asperities, and the cones are arranged in different ways along two directions. Secondly, according to the mechanical analysis of a rigid conical punch on a half-space, the theoretical relationship between the average pressure of the micro contact area and the property parameters of a conical punch is obtained. Meanwhile, the calculation formula of the average pressure is given under the reasonable assumptions, which is related with the asperity’s deformation and the contact pressure. Finally, combining two theoretical relationships above, the quantitative analysis method for micro asperity’s deformation of two rough surfaces in contact is provided by using the average pressure as a connection bridge.

APA, Harvard, Vancouver, ISO, and other styles

31

LaPlant, F., E. J. Hutchinson, and D. Ben-Amotz. "Raman Measurements of Localized Pressure Variations in Lubricants Above the Glass Transition Pressure." Journal of Tribology 119, no. 4 (October 1, 1997): 817–22. http://dx.doi.org/10.1115/1.2833891.

Full text

Abstract:

Spatial pressure variations in synthetic lubricants contained in a static high-pressure diamond anvil cell (DAC), as well as in a loaded model bearing contact device, have been measured using the frequency shift of the lubricant’s Raman vibrational modes. Long-lived pressure fluctuations of ±0.5 GPa, with a relaxation time of several days, are observed m the static high pressure systems at an average pressure of 2.5 GPa. Evidence for rapidly varying pressure fluctuations in a concentrated contact is inferred from the increase in lubricant Raman linewidths. These results raise questions about key assumptions made in modeling EHD contacts. It is suggested that the present results are closely linked to recent observations of shear localization made by Winer and Bair.

APA, Harvard, Vancouver, ISO, and other styles

32

Simonian, Peter T., Patrick S. Sussmann, Thomas L. Wickiewicz, George A. Paletta, and Russell F. Warren. "Contact Pressures at Osteochondral Donor Sites in the Knee." American Journal of Sports Medicine 26, no. 4 (July 1998): 491–94. http://dx.doi.org/10.1177/03635465980260040201.

Full text

Abstract:

The purposes of this study were to determine whether any of the commonly recommended osteochondral donor sites are nonarticulating throughout a functional range of knee motion, and to determine the differential contact pressures for these sites. Ten commonly recommended sites for osteochondral harvest were evaluated with pressure-sensitive film through a functional range of motion with a model that simulated nonweightbearing resistive extension of the knee. All 10 donor sites demonstrated a significant contact pressure through 0° to 110° of knee motion. The different color density measurements between donor sites were also significant. Although donor sites 1, 2, 9, and 10 demonstrated significantly less contact pressure than the sites with the greatest contact pressure, the difference in mean pressures was small. No osteochondral donor site tested was free from contact pressure. It is currently unknown whether articular contact at these osteochondral donor sites will lead to degenerative changes or any other problems.

APA, Harvard, Vancouver, ISO, and other styles

33

Marshall, M. B., R. Lewis, R. S. Dwyer-Joyce, U. Olofsson, and S. Björklund. "Experimental Characterization of Wheel-Rail Contact Patch Evolution." Journal of Tribology 128, no. 3 (March 21, 2006): 493–504. http://dx.doi.org/10.1115/1.2197523.

Full text

Abstract:

The contact area and pressure distribution in a wheel/rail contact is essential information required in any fatigue or wear calculations to determine design life, re-grinding, and maintenance schedules. As wheel or rail wear or surface damage takes place the contact patch size and shape will change. This leads to a redistribution of the contact stresses. The aim of this work was to use ultrasound to nondestructively quantify the stress distribution in new, worn, and damaged wheel-rail contacts. The response of a wheel/rail interface to an ultrasonic wave can be modeled as a spring. If the contact pressure is high the interface is very stiff, with few air gaps, and allows the transmission of an ultrasonic sound wave. If the pressure is low, interfacial stiffness is lower and almost all the ultrasound is reflected. A quasistatic spring model was used to determine maps of contact stiffness from wheel/rail ultrasonic reflection data. Pressure was then determined using a parallel calibration experiment. Three different contacts were investigated; those resulting from unused, worn, and sand damaged wheel and rail specimens. Measured contact pressure distributions are compared to those determined using elastic analytical and numerical elastic-plastic solutions. Unused as-machined contact surfaces had similar contact areas to predicted elastic Hertzian solutions. However, within the contact patch, the numerical models better reproduced the stress distribution, as they incorporated real surface roughness effects. The worn surfaces were smoother and more conformal, resulting in a larger contact patch and lower contact stress. Sand damaged surfaces were extremely rough and resulted in highly fragmented contact regions and high local contact stress.

APA, Harvard, Vancouver, ISO, and other styles

34

Müser, Martin, and Anle Wang. "Contact-Patch-Size Distribution and Limits of Self-Affinity in Contacts between Randomly Rough Surfaces." Lubricants 6, no. 4 (September 20, 2018): 85. http://dx.doi.org/10.3390/lubricants6040085.

Full text

Abstract:

True contact between solids with randomly rough surfaces tends to occur at a large number of microscopic contact patches. Thus far, two scaling regimes have been identified for the number density n ( A ) of contact-patch sizes A in elastic, non-adhesive, self-affine contacts. At small A, n ( A ) is approximately constant, while n ( A ) decreases as a power law at large A. Using Green’s function molecular dynamics, we identify a characteristic (maximum) contact area A c above which a superexponential decay of n ( A ) becomes apparent if the contact pressure is below the pressure p cp at which contact percolates. We also find that A c increases with load relatively slowly far away from contact percolation. Results for A c can be estimated from the stress autocorrelation function G σ σ ( r ) with the following argument: the radius of characteristic contact patches, r c , cannot be so large that G σ σ ( r c ) is much less than p cp 2 . Our findings provide a possible mechanism for the breakdown of the proportionality between friction and wear with load at large contact pressures and/or for surfaces with a large roll-off wavelength.

APA, Harvard, Vancouver, ISO, and other styles

35

Motie-Shirazi, Mohsen, Matías Zañartu, Sean D. Peterson, Daryush D. Mehta, James B. Kobler, Robert E. Hillman, and Byron D. Erath. "Toward Development of a Vocal Fold Contact Pressure Probe: Sensor Characterization and Validation Using Synthetic Vocal Fold Models." Applied Sciences 9, no. 15 (July 26, 2019): 3002. http://dx.doi.org/10.3390/app9153002.

Full text

Abstract:

Excessive vocal fold collision pressures during phonation are considered to play a primary role in the formation of benign vocal fold lesions, such as nodules. The ability to accurately and reliably acquire intraglottal pressure has the potential to provide unique insights into the pathophysiology of phonotrauma. Difficulties arise, however, in directly measuring vocal fold contact pressures due to physical intrusion from the sensor that may disrupt the contact mechanics, as well as difficulty in determining probe/sensor position relative to the contact location. These issues are quantified and addressed through the implementation of a novel approach for identifying the timing and location of vocal fold contact, and measuring intraglottal and vocal fold contact pressures via a pressure probe embedded in the wall of a hemi-laryngeal flow facility. The accuracy and sensitivity of the pressure measurements are validated against ground truth values. Application to in vivo approaches are assessed by acquiring intraglottal and VF contact pressures using a synthetic, self-oscillating vocal fold model in a hemi-laryngeal configuration, where the sensitivity of the measured intraglottal and vocal fold contact pressure relative to the sensor position is explored.

APA, Harvard, Vancouver, ISO, and other styles

36

Anaya-Dufresne, M., and G. B. Sinclair. "Towards a Reynolds Equation for Gas Lubricated Bearings When Contact Occurs." Journal of Tribology 124, no. 2 (March 7, 2001): 266–73. http://dx.doi.org/10.1115/1.1398548.

Full text

Abstract:

The various existing forms of Reynolds equation are known to yield pressure fields which are unbounded and nonphysical when contact occurs. With a view to developing a Reynolds equation that is suitable for contact, here we revisit Taylor’s plate scraping problem for incompressible flow. This problem has an infinite pressure where the scraper contacts the plate. By suitably modifying Maxwell’s slip condition, the scraping problem can be reformulated so as to lead to finite pressures. This is shown locally via asymptotics, and globally via convergence checks. The approach looks sufficiently promising to consider the further development needed for the compressible flow present in gas lubricated bearings.

APA, Harvard, Vancouver, ISO, and other styles

37

MOLLAMAHMUTOGLU, C., S. GANAPATHI, and J. K. GOOD. "Pressures on webs in wound rolls due to winding and contact." February 2014 13, no. 2 (March 1, 2014): 41–50. http://dx.doi.org/10.32964/10.32964/tj13.2.41.

Full text

Abstract:

Paper, film, and metallic webs have designed surfaces. Process engineers design these surfaces to ensure they will coat or print correctly. In some cases, such as tissue, the manufactured surface is designed to provide softness. After the web is formed, care must be taken to maintain the web surface for the intended use or for subsequent processing. Web surfaces can be damaged by contact pressure, which is due to multiple sources. Tissues can suffer decreased loft and softness as a result of excessive pressure. Winding webs into rolls creates pressure on each web layer that varies with radial location. Almost all high speed winders must employ a nip roller in contact with the outer surface of the winding roll to prevent air entrainment. The nip roller, which may or may not be covered with an elastomer, induces local dynamic pressures where it contacts the winding roll that travel at the surface velocity of the winding roll. After rolls are wound, they can witness additional surface contact pressure. Often rolls are stored on flat surfaces and the dead weight of the roll induces contact pressure. In other cases, the roll may be moved by a clamp truck that employs hydraulic pressure to clamp and lift the wound roll. The objective of this paper is to demonstrate a method by which the total pressure in a web due to winding and to contact can be determined. Wound rolls of newsprint and polyester will be subjected to compression tests to verify the method.

APA, Harvard, Vancouver, ISO, and other styles

38

Bhaumik, Shankar, S. R. Kumar, and Adepu Kumaraswamy. "Experimental Investigation and FE Modelling of Contact Mechanics Phenomenon in Reciprocating Hydraulic U-Seals for Defence Applications." Applied Mechanics and Materials 592-594 (July 2014): 1950–54. http://dx.doi.org/10.4028/www.scientific.net/amm.592-594.1950.

Full text

Abstract:

In this article, an attempt was made to investigate the contact mechanics phenomenon of the reciprocating hydraulic U-seal by measuring friction forces at various pressures and velocities. The inlet fluctuating pressure and the rod speed was simultaneously performed at the peak pressures of 10, 20 and 30MPa and the rod speeds of, 0.12, 0.3 and 0.5 m/s. The distribution of the contact pressure at the seal/rod interface was calculated along the contact surface at pressures of 10, 20 and 30MPa using FE model. Friction measurement of reciprocating seals by experimental results demonstrated that the velocity of the rod and seal pressure influences the seal performance considerably. Furthermore, the numerical analysis undertaken to determine the contact pressure to compute friction force was in good agreement with the experimental results.

APA, Harvard, Vancouver, ISO, and other styles

39

Tsukamoto, Takashiro, Masayoshi Esashi, and Shuji Tanaka. "Carbon-Nanotube-Enhanced Thermal Contactor in Low Contact Pressure Region." Japanese Journal of Applied Physics 49, no. 7 (July 5, 2010): 070210. http://dx.doi.org/10.1143/jjap.49.070210.

Full text

APA, Harvard, Vancouver, ISO, and other styles

40

Agzamov, M., I. Radjabov, and D. Yuldashev. "Research of the reasons of increased drop in cotton seeds after generation with reduced density of raw roller." IOP Conference Series: Earth and Environmental Science 939, no. 1 (December 1, 2021): 012072. http://dx.doi.org/10.1088/1755-1315/939/1/012072.

Full text

Abstract:

Abstract Results of researches on definition of influence of density of the raw roller on pubescence of cotton seeds are given in article. The received mathematical model for calculation of contact pressure and movement of the raw roller in the form of a system from six equations with six unknown. The numerical results calculated on the computer. Sizes of shift and contact pressure for the set physic-mechanical and geometrical parameters of a system are determined. It is established that contact pressure significantly depends on elasticity (density) and angular speed of the raw roller. On the basis of the graphic data of contact pressure and contact movement of the raw roller received results of calculations the conclusion that with reduction of density of the raw roller conditions of capture of a short cotton slice worsen. The fact that the contact pressure and movement fluctuate during time is the reason of it, i.e. in the beginning the short cotton slice contacts to a saw, but during fractions of a second this contact is lost, also contact pressure similarly changes. Results of theoretical researches proved increase in a full pubescence of seeds after gin with reduction of density of the raw roller, i.e. one of the reasons of it is deterioration in conditions of capture of short cotton slices a saw - fluctuations of contact pressure and contact movement of the raw roller.

APA, Harvard, Vancouver, ISO, and other styles

41

Chang, L., and Yongwu Zhao. "On the Sensitivity of the Asperity Pressures and Temperatures to the Fluid Pressure Distribution in Mixed-Film Lubrication." Journal of Tribology 122, no. 1 (June 10, 1999): 77–85. http://dx.doi.org/10.1115/1.555331.

Full text

Abstract:

This paper studies the sensitivities of the asperity pressures and temperatures to the fluid pressure distribution in concentrated contacts operating in the regime of mixed-film lubrication. Two fluid pressure distributions are used in the study. One is a Hertz-like distribution that neglects micro-EHL responses of the lubricant, and the other models the micro-EHL effects with significant pressure rippling. The asperity pressures and temperatures are deterministically calculated in time by numerically solving the asperity-contact and the transient energy equations as the two surfaces move relative to each other. The contact is simulated for sufficient time duration until the samples of the calculated asperity variables reach a statistical equilibrium that reflects the random-process nature of the problem. Parametric analyses are carried out that cover a wide range of operating conditions of practical interest. The results obtained consistently suggest that the asperity pressures and temperatures are not sensitively related to the fluid pressure. This insensitivity supports the use of any fluid pressure distribution consistent with the underlying mixed-film problem, rather than determining it by numerically solving the Reynolds equation at every time step of the simulation process. The study lays a foundation on which to advance modeling of the mixed-film contacts with a proper balance among model robustness, computational efficiency and solution accuracy. [S0742-4787(00)01101-2]

APA, Harvard, Vancouver, ISO, and other styles

42

Jeremic, B., D. Vukelic, P. M. Todorovic, I. Macuzic, M. Pantic, D. Dzunic, and B. Tadic. "Static friction at high contact temperatures and low contact pressure." Journal of Friction and Wear 34, no. 2 (March 2013): 114–19. http://dx.doi.org/10.3103/s1068366613020037.

Full text

APA, Harvard, Vancouver, ISO, and other styles

43

Hsieh, K. T., S. Satapathy, and M. T. Hsieh. "Effects of Pressure-Dependent Contact Resistivity on Contact Interfacial Conditions." IEEE Transactions on Magnetics 45, no. 1 (January 2009): 313–18. http://dx.doi.org/10.1109/tmag.2008.2008876.

Full text

APA, Harvard, Vancouver, ISO, and other styles

44

NAGATANI, Haruo, and Akitoshi IMOU. "Contact Pressure and Shear Stress Analysis on Conforming Contact Problem." Journal of Advanced Mechanical Design, Systems, and Manufacturing 2, no. 6 (2008): 1055–66. http://dx.doi.org/10.1299/jamdsm.2.1055.

Full text

APA, Harvard, Vancouver, ISO, and other styles

45

Sharifi Miavaghi, Amir, Haleh Kangarlou, and Mehdi Eskandarzade. "Comparison between frictional behavior of the soft and brittle materials at different contact pressures." Lebanese Science Journal 18, no. 1 (June 21, 2017): 98–105. http://dx.doi.org/10.22453/lsj-018.1.098105.

Full text

Abstract:

Coefficient of friction changed significantly by the change in contact pressure. Experimental measurement of the coefficient of friction in different contact pressures can be useful in numerical and analytical analysis of many engineering problems, such as metal forming process. This study dedicated to investigate the sensitivity of the friction coefficient to changes in contact pressures. To aim this goal the special tribometer device has been fabricated and the coefficient of friction of the soft and brittle metals when sliding with a low speed on a rigid body are measured for different contact pressures. The friction sensitivity of the soft (copper and aluminum) and brittle (steel) samples to changes in contact pressure are compared and discussed. The results showed that both brittle and soft metals are highly sensitive for change in contact pressure but their behaviour is slightly different. While the coefficient of friction of the steel sample when sliding on a steel substrate is reduced sharply by a little increase in contact pressure; the coefficient of friction of the soft material when sliding on a steel substrate is reduced slowly depending on the magnetude of the applied normal load.

APA, Harvard, Vancouver, ISO, and other styles

46

Zhang, Fu Xiang, Bing Yin Ji, Xiang Tong Yang, Yong Han, and Ze Liang Chang. "Finite Element Numerical Simulation of Tubing Premium Connection." Applied Mechanics and Materials 217-219 (November 2012): 1622–27. http://dx.doi.org/10.4028/www.scientific.net/amm.217-219.1622.

Full text

Abstract:

The environment and load condition of tubing is severe in high pressure wells. The sealability and joint strength of tubing string plays an important role in production operation. In this study, the makeup, sealability and joint strength was analyzed from conditions of make-up loading, tension loading, compression loading and internal pressure loading by finite element method. The makeup torque, the contact pressure distributions of metal seal along the axis and the stress distributions of threaded connection are given. The results show that under tension loading, compression loading and internal pressure, the overall stress level of threaded connection is lower than of pipe. The anti-compression performance and joint strength of threaded connection is greater than of pipe. The contact pressures of metal seal maintain relatively high level of contact pressures under tension loading, compression loading and internal pressure. Tension loading and compression loading reduces the sealing performance and the internal pressure increases the sealing performance from the integral of the contact pressure.

APA, Harvard, Vancouver, ISO, and other styles

47

Borgarelli, Nicola, and Roberto Marsili. "OS03W0382 Measurement of contact pressure distributions between mechanical components by thermoelasticity." Abstracts of ATEM : International Conference on Advanced Technology in Experimental Mechanics : Asian Conference on Experimental Mechanics 2003.2 (2003): _OS03W0382. http://dx.doi.org/10.1299/jsmeatem.2003.2._os03w0382.

Full text

APA, Harvard, Vancouver, ISO, and other styles

48

Voloshin, S. M. "Terms of repair works and forecasting of terms of service of contacts of disassembly type in conditions of incomplete of output information." Naukovij žurnal «Tehnìka ta energetika» 11, no. 3 (November 18, 2020): 17–22. http://dx.doi.org/10.31548/machenergy2020.03.017.

Full text

Abstract:

Collapsible contact joints are the most numerous elements of electrical installations. The efficiency of the contacts, their reliability to a large extent depends on the modes of electric current and temperature, contact pressure, etc. Modification of modes and operation time lead to an increase in the resistance of the contacts, the temperature of their heating and possible thermal destruction. Traditional means for controlling the pressure in the contacts when changing the temperature regime are steel plate springs. Previous investigations have established that these means only partially solve the problem of regulation of contact pressure. An alternative to traditional means is the innovative development of dynamic pressure control tools based on the use of functional alloys with the shape memory effect. The mathematical analysis of terms of carrying out repair works and service life of collision type contacts with the use of probability theory in the conditions of incompleteness of the initial information is carried out. The research substantiates that the use of dynamic method of control of the thermomechanical regime of collapsible contacts allows to stabilize pressure and extend the life of collapsible contacts by 3-4 times.

APA, Harvard, Vancouver, ISO, and other styles

49

Johansson, L. "Numerical Simulation of Contact Pressure Evolution in Fretting." Journal of Tribology 116, no. 2 (April 1, 1994): 247–54. http://dx.doi.org/10.1115/1.2927205.

Full text

Abstract:

In the present paper an algorithm for frictional contact between two elastic bodies is presented. The algorithm is applied to the calculation of the evolution of contact pressure between two elastic bodies when material is being removed by fretting. To this end Archard’s law of wear is implemented into the algorithm. It is noticed that the calculated pressures after a period of fretting differ considerably from the initial Hertz type pressures. Further, it is noted that numerical instabilities can occur in explicit type wear calculations, and a stability criterion is suggested.

APA, Harvard, Vancouver, ISO, and other styles

50

Shen, Fei, and Liao-Liang Ke. "Numerical Study of Coupled Electrical-Thermal-Mechanical-Wear Behavior in Electrical Contacts." Metals 11, no. 6 (June 12, 2021): 955. http://dx.doi.org/10.3390/met11060955.

Full text

Abstract:

Electrical contacts involve complicated electrical, thermal, and mechanical phenomena. Fretting wear as a surface damage mechanism significantly weakens the performance of electrical contact components. In this study, a numerical approach is developed to investigate the electrical-thermal-mechanical-wear coupling behavior of electrical contacts. An electrical contact conductance law is used with the current conservation model to evaluate the electrical behavior. A transient heat transfer model, including the Joule heating behavior and a thermal contact conductance law, is employed to calculate the temperature field. Both contact conductance laws are related to the contact pressure distribution obtained by the contact stress analysis. Based on the predicted contact stress and relative slip on contact surfaces, the energy wear model is used to study the evolution of fretting wear depth and contact surface geometry. The material properties in these models are temperature-dependent. The proposed numerical approach is implemented in a finite element modeling of electrical contacts, which is validated by comparing the predicted and experimental results of the wear scar profile. The effects of the fretting wear on the electric potential, current density, contact resistance, temperature, and contact pressure are numerically studied.

APA, Harvard, Vancouver, ISO, and other styles

Journal articles on the topic 'Contact pressure'

Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles