Direct Evaluation of Coulomb Friction Coefficient from Sheet Strip Stretch Test on a Cylinder Surface

2014 ◽  
Vol 966-967 ◽  
pp. 242-248
Author(s):  
Celalettin Karadogan ◽  
Hasan Ali Hatipoglu
Keyword(s):  
Friction Coefficient ◽  
Sheet Metal ◽  
Measurement System ◽  
Cylindrical Surface ◽  
Strain Measurement ◽  
Strain Distribution ◽  
Coulomb Friction ◽  
Cylinder Surface ◽  
Optical Strain Measurement ◽  
Optical Strain

Knowing the flow curve of a sheet metal, strain distribution on a sheet strip may be used to roughly but quickly evaluate the Coulomb friction coefficient. Strain distribution on the strip being stretched on a cylindrical surface of interest may be measured by an optical strain measurement system. This could be used to estimate the stresses on the specimen. The capstan equation is then used to roughly evaluate the coefficient of friction acting between the sheet strip and the cylindrical surface. Validation of the approach is done using the simulation of the process. The corresponding experiments can be performed easily on a sheet metal testing device equipped with an optical strain measurement system, which is commonly used for the experimental evaluation of FLCs.

An optical strain measurement system for asphalt mixtures

2008 ◽  
Vol 42 (4) ◽  
pp. 427-441 ◽  
Author(s):  
Bjorn Birgisson ◽  
Antonio Montepara ◽  
Elena Romeo ◽  
Riccardo Roncella ◽  
Reynaldo Roque ◽  
...  
Keyword(s):  
Measurement System ◽  
Strain Measurement ◽  
Asphalt Mixtures ◽  
Optical Strain Measurement ◽  
Optical Strain

Monitoring High Temperature Steam Pipes Using Optical Strain Measurement Techniques

2006 ◽  
Vol 5-6 ◽  
pp. 145-152 ◽  
Author(s):  
Andrew Morris ◽  
John P. Dear ◽  
Miltiadis Kourmpetis
Keyword(s):  
Wind Turbine ◽  
Strain Measurement ◽  
Measurement Techniques ◽  
Turbine Blades ◽  
Monitoring Methods ◽  
Wind Turbine Blades ◽  
Optical Strain Measurement ◽  
Optical Strain ◽  
High Temperature Steam ◽  
Steam Pipes

Optical strain measurement techniques have been extensively developed in recent years in order to cope in various environments. Power stations and wind turbine blades can provide challenging environments for the use of a measurement technique. There are, however, many installation problems to be overcome. For example, there is the need to have regard for the hostile environment in steam generating plant and the demanding conditions to which wind turbine blades are subjected. Ideally the outputs from individual sensors would be used for continuous remote monitoring. However, measurements can also be useful each time the plant is shut down during a plant outage; which would be used to complement data from existing proven rugged monitoring methods. This paper addresses the monitoring of pressurized steam pipes as to their micro-strain growth related to time in service. This paper presents the progress made in the developing of a ruggedised digital speckle ‘sensor’ and associated image capture system. The effect of subsurface defects in the strain distribution is examined.

Comparative Study of As-Built Geometric and Mechanical Properties of Additively Manufactured Ceramics

2018 ◽  
Author(s):  
John C. Steuben ◽  
Athanasios P. Iliopoulos ◽  
John G. Michopoulos
Keyword(s):  
Mechanical Properties ◽  
Strain Measurement ◽  
High Performance ◽  
Marked Decrease ◽  
Measurement Techniques ◽  
Direct Ink Writing ◽  
Optical Strain Measurement ◽  
Broad Variety ◽  
Optical Strain ◽  
Am Processes

Additive Manufacturing (AM) encompasses a broad variety of fabrication techniques characterized by successive additions of mass and/or energy to a build domain. AM processes have been developed for a wide variety of feedstock materials, including metals, polymers, and ceramics. In the present work we study the AM of ceramics using the Direct Ink Writing (DIW) technique. We performed comparative studies between additively manufactured and conventionally manufactured test articles, in order to quantify the variations in output geometry and mechanical properties induced by the DIW process. Uniaxial tests are conducted using high-performance optical strain measurement techniques. In particular, it is shown that the DIW-produced specimens exhibit anisotropic shrinkage when fired, as well as a marked decrease in stiffness and ultimate strength. We conclude with a discussion of potential mechanisms which may be responsible for these property degradations, and introduce potential adaptations to the DIW AM process that may be effective in combating them.

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