On the Validation of a Multiphysics Theory for a Static Contact With Rough Surfaces

2014 ◽  
Author(s):  
John G. Michopoulos ◽  
Marcus Young ◽  
Athanasios Iliopoulos ◽  
Harry N. Jones
Keyword(s):  
Contact Resistance ◽  
Contact Surface ◽  
Mechanical Load ◽  
Acquired Resistance ◽  
Contact Theory ◽  
Electric Current Pulse ◽  
Mechanical Pressure ◽  
Annular Disk ◽  
Static Contact ◽  
Hollow Cylinders

In an effort to address the validation of a recently developed multifield and multiscale rough contact theory we are applying it for a particular experiment. The experiment involves the contact between two hollow cylinders with an annular disk in between them. The contact surface is rough and the entire stack is exposed to compressive mechanical load and a high electric current pulse. Solving the necessary multi-physics partial differential equations leads to establishing the spatiotemporal distribution of relevant fields and the identification of the contact resistance as a function of mechanical pressure and current. In addition to providing typical results for all selected fields present during the experiment and the simulation, we also provide a comparison between the experimentally acquired resistance histories with the numerically derived ones to address validation aspects of the general multiphysics contact theory.

Towards Static Contact Multiphysics of Rough Surfaces

2012 ◽  
Author(s):  
John G. Michopoulos ◽  
Athanasios Iliopoulos ◽  
Marcus Young
Keyword(s):  
Electric Current ◽  
Mechanical Load ◽  
Bulk Material ◽  
Rough Surfaces ◽  
Thermal Response ◽  
Surface Characteristics ◽  
Current Status ◽  
Plastic Behavior ◽  
Mechanical Pressure ◽  
Static Contact

This paper is describing the current status of ongoing work on developing a comprehensive modeling and simulation infrastructure capable of addressing the multiphysics behavior aspects of rough surfaces in contact. The electrical and thermal response of bodies in contact under the influence of mechanical load electric currents and thermal fluxes, is a topic of interest for many application areas. We are presenting a multiscale theory leading to derivations of expressions of electric and thermal conductivities for the case of static contact. The associated model contains both an asperity based comprehensive model as well as its continuum level coupling. The mechanical pressure and the repulsion effect from electric current through the micro-contacts as well as temperature and strain rate dependence of the plastic behavior of the asperity are accounted for as well. This formalism enables the derivation of physical properties from surface topography and bulk material properties for the interface between two rough surfaces in contact. Numerical analysis results present the dependence of the derived properties from the surface characteristics applied external load and the electric current.

Multiscale and Multifield Multiphysics of High Current Pulse Static Contact With Rough Surfaces

2013 ◽  
Author(s):  
John G. Michopoulos ◽  
Marcus Young ◽  
Athanasios Iliopoulos
Keyword(s):  
Electric Current ◽  
Current Pulse ◽  
Mechanical Load ◽  
Bulk Material ◽  
Rough Surfaces ◽  
High Current ◽  
Mechanical Pressure ◽  
Static Contact ◽  
Macro Scale ◽  
Scale Properties

We are presenting a multi-field and multiscale theory leading to derivations of physical properties from surface topography and bulk material properties for the interface between two rough surfaces in contact activated by mechanical load and high current pulses. At the macro-scale our proposed model involves multi-field coupling of conduction and induction currents with heat conduction induced by Joule heating. The structural mechanics of the conducting materials are also considered. At the meso-scale and micro-scale the associated model contains an asperity based comprehensive model that leads to homogenized macro scale properties for the interface boundary. The mechanical pressure and the repulsion effect from electric current through the micro-contacts are accounted for as well. Numerical analysis results illustrate the dependence of the derived properties on the surface characteristics, external load and the electric current. Finally, the entire framework is applied to an actual conductor configuration of hollow cylinders under compression and a high current pulse to demonstrate the feasibility of the entire approach.

Growth Law of the Oxide Film Formed on the Tin Plated Contact Surface and Its Contact Resistance Characteristic

2009 ◽  
Author(s):  
Yuuya Nabeta ◽  
Yasushi Saitoh ◽  
Shigeru Sawada ◽  
Yasuhiro Hattori ◽  
Terutaka Tamai
Keyword(s):  
Oxide Film ◽  
Contact Resistance ◽  
Contact Surface ◽  
Resistance Characteristic

Object Reconfiguration with Multiple Robotic Arms Using An Additional Static Contact Surface

2000 ◽  
Vol 33 (27) ◽  
pp. 267-272
Author(s):  
Gábor Vass ◽  
Shahram Payandeh ◽  
Béla Lantos
Keyword(s):  
Contact Surface ◽  
Robotic Arms ◽  
Static Contact

Precision Analytic Algorithms on Contact Stiffness of Parts

2012 ◽  
Vol 271-272 ◽  
pp. 1067-1072
Author(s):  
Fei Wan ◽  
Guo Xi Li ◽  
Zhi Hua Rao
Keyword(s):  
Dynamic Characteristics ◽  
Contact Surface ◽  
Contact Stiffness ◽  
Fractal Theory ◽  
Contact Theory ◽  
Cross Linking ◽  
Surface Model ◽  
Hertz Contact ◽  
Hertz Contact Theory ◽  
The Relationship

The couplings join the various parts together to form an assembly through contact surface, which the stiffness plays an important role for the machine characteristics. Hertz contact theory constructed the relationship between preload and stiffness from a macro perspective, while MB fractal theory presented the mapping between preload and stiffness from microscopic viewpoint. A more precise contact surface model about load and stiffness is established through learning from each other and cross-linking to prepare for analyzing the whole dynamic characteristics.

Comparative study of ring yarn properties spun with static and rotary grooved contact surfaces

2017 ◽  
Vol 88 (16) ◽  
pp. 1812-1823 ◽  
Author(s):  
Hao Yu ◽  
Keshuai Liu ◽  
Chen Jun ◽  
Chiyu Fu ◽  
Zhigang Xia ◽  
...  
Keyword(s):  
Theoretical Analysis ◽  
Contact Surface ◽  
Surface Friction ◽  
Significant Deterioration ◽  
Spun Yarn ◽  
Yarn Properties ◽  
Static Contact ◽  
Ring Spun Yarn ◽  
Grooved Surface ◽  
Yarn Hairiness

Spinning with a static contact surface is an energy-saving method to reduce spun yarn hairiness; however, the spun yarn irregularity and tensile properties are deteriorated. To prohibit the deteriorations, this paper introduces a rotary grooved surface contacting ring spinning strand within the yarn formation zone. In theory, the modeling analysis of spinning with contact surface is conducted to reveal the prohibition mechanism of yarn irregularity and tensile property deteriorations for a rotary grooved surface. Theoretical analysis results indicated that groove-yarn surface friction could wrap the concentrated hairs onto yarn stem while block inflowing twists to the spinning strangle zone; the rotary grooved surface could reduce twist blockage and hair wrapping concentrations to better the situation after a comparison with the static grooved surface. Then, two kinds of specially-designed grooved cylinders (one was rotatable while the other was static) were used to validate the theoretical analysis. The experimental results showed that, unlike the static grooved cylinder which significantly deteriorated the original yarn unevenness CVm, the rotary achieved significant hairiness reduction without any significant deterioration of other yarn properties. This might be due to the decreased friction and twist propagation for the rotary grooved cylinder contacting the spinning strand. In this case, spinning with a rotary grooved cylinder was preferably applied in the first step to control ring spun yarn hairiness.

Thermoviscoelastic behavior of a short fiber-reinforced polymer hollow cylinder accounting for porosity

2016 ◽  
Vol 51 (19) ◽  
pp. 2779-2791 ◽  
Author(s):  
Hong-Liang Dai ◽  
Ting Dai ◽  
Wei-Feng Luo
Keyword(s):  
Hollow Cylinder ◽  
Integral Transform ◽  
Mechanical Load ◽  
Coefficient Of Thermal Expansion ◽  
Short Fiber ◽  
Fiber Reinforced Polymer ◽  
Fiber Reinforced ◽  
Cylindrical Structures ◽  
Reinforced Polymer ◽  
Hollow Cylinders

In this paper, thermoviscoelastic behavior of a hollow cylinder made of short fiber-reinforced polymer considering porosity is investigated by an analytical method. Material properties, except the Poisson’s ratio and coefficient of thermal expansion, are assumed to be changed with the volume of constituents and porosity. Utilizing the finite Hankle integral transform and Laplace transform, analytical solutions for thermoviscoelastic behaviors of short fiber-reinforced polymer hollow cylinders under thermal and mechanical loads are obtained. Numerical examples show the influences of thermal load, mechanical load, and material porosity on the thermoviscoelastic behaviors of short fiber-reinforced polymer cylindrical structures.

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