A Methodology for Real Time Surface Strain Measurement for Stamping Through Non-Contact Optical Strain Measurement System

The quality of stamp formed parts depends on a number of variables. Numerical studies based on finite element analysis can provide evolution of strain during forming and correlate with different failures of the formed parts. This study presents a methodology of capturing the evolution of strain during forming through a photogrammetric method. An open die was used to monitor the strain evolution of domed parts. The forming characteristic of a fibre-metal laminate system was compared to a monolithic aluminum alloy to elucidate the differences in the strain evolution during forming. It was found that the two materials exhibited different strain evolution during forming and this affected the failure behavior of the formed parts.

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

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.966-967.242 ◽

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.

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An investigation of photoresists for use in optical strain analysis

Journal of Strain Analysis ◽

10.1243/03093247v053162 ◽

1970 ◽

Vol 5 (3) ◽

pp. 162-168 ◽

Cited By ~ 8

Author(s):

A Luxmoore ◽

R Hermann

Keyword(s):

Strain Measurement ◽

Strain Analysis ◽

Surface Strain ◽

High Contrast ◽

Moire Method ◽

Optical Strain

Some commercial photoresists have been examined to assess their suitability for use with the moiré method of surface-strain measurement. As most of these materials do not produce a pattern of high contrast directly, some etching and plating procedures are also described. Combined with correct illumination, these processes will produce grids of sufficient contrast for most applications.

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Monitoring High Temperature Steam Pipes Using Optical Strain Measurement Techniques

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.5-6.145 ◽

2006 ◽

Vol 5-6 ◽

pp. 145-152 ◽

Cited By ~ 2

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.

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