scholarly journals Optical strain measurement for the modeling of surgical meshes and their porosity

2018 ◽  
Vol 4 (1) ◽  
pp. 181-184
Author(s):  
Andreas J. Horbach ◽  
Manfred Staat
Keyword(s):  
Nonlinear Modeling ◽  
Effective Porosity ◽  
Deformation Measurement ◽  
Full Field ◽  
Surgical Meshes ◽  
Optical Strain Measurement ◽  
Large Elastic Deformation ◽  
Optical Strain ◽  
Global Deformation ◽  
Change Of Porosity

AbstractThe porosity of surgical meshes makes them flexible for large elastic deformation and establishes the healing conditions of good tissue in growth. The biomechanic modeling of orthotropic and compressible materials requires new materials models and simulstaneoaus fit of deformation in the load direction as well as trannsversely to to load. This nonlinear modeling can be achieved by an optical deformation measurement. At the same time the full field deformation measurement allows the dermination of the change of porosity with deformation. Also the socalled effective porosity, which has been defined to asses the tisssue interatcion with the mesh implants, can be determined from the global deformation of the surgical meshes.

Assessing the Feasibility of Monitoring the Condition of Historic Tapestries Using Engineering Techniques

2007 ◽  
Vol 347 ◽  
pp. 187-192 ◽  
Author(s):  
Janice M. Dulieu-Barton ◽  
M. Sahin ◽  
F.J. Lennard ◽  
D.D. Eastop ◽  
A.R. Chambers
Keyword(s):  
Optical Fibre ◽  
Strain Measurement ◽  
Measurement Techniques ◽  
Mechanical Tests ◽  
Textile Material ◽  
Full Field ◽  
Strain Monitoring ◽  
Optical Strain Measurement ◽  
Optical Strain

The findings of a year-long programme carried out by a multidisciplinary engineering/conservation team are described. A mass-produced textile material that can be used to represent tapestries is identified and mechanical tests are detailed which demonstrate it behaves in a similar way to tapestry. The feasibility of using optical fibre sensors, full-field optical strain measurement techniques and thermography for monitoring tapestry degradation is assessed. The results of preliminary findings are presented and a rationale is developed for in-situ quantitative strain monitoring of tapestries.

Recent Developments in ARCMAC and Related Creep Strain Monitoring Techniques

2011 ◽  
Author(s):  
Aditya Narayanan ◽  
Andy Morris ◽  
Catrin Mair Davies ◽  
John Dear
Keyword(s):  
High Temperature ◽  
Creep Strain ◽  
High Temperatures ◽  
Strain Measurement ◽  
Measurement Techniques ◽  
Image Correlation ◽  
Camera System ◽  
Full Field ◽  
Optical Strain Measurement ◽  
Optical Strain

Developments have been made to E.ON’s Auto-Reference Creep Management and Control (ARCMAC) system to measure strain at high temperature using both Digital Image Correlation (DIC) and conventional ARCMAC techniques. These techniques are aimed at measuring creep strain rate in power plant steam pipes and associated weldments operating at high temperatures and pressures for the purposes of estimation of remaining life of such components. The ARCMAC optical strain measurement system is used to measure point to point strain through the capture and analysis of images of a pair of Inconel gauges, with Silicon Nitride spheres, welded to steam pipe and other components. A modified ARCMAC image capture system has been developed using a DSLR camera, with higher resolution offering the potential to capture DIC images suitable for measuring strain accurately. Development of the system to measure strain using both ARCMAC gauges and DIC at high temperature offers the potential to obtain full-field strain measurement across features such as welds, giving a useful improved research tool for creep evaluation. The recently developed DSLR-ARCMAC camera system has been optimised to measure strain using a number of optical strain measurement techniques, including the ARCMAC strain measurement procedure and DIC. These techniques have been used to measure strain during room temperature tensile tests prior to their use at high temperatures. Following these experiments, creep testing of CMV steel specimens is planned paying particular attention to the evaluation of the ARCMAC system at high temperatures.

On the Calibration of Optical Full-Field Strain Measurement Systems

2006 ◽  
Vol 3-4 ◽  
pp. 397-402 ◽  
Author(s):  
Maurice P. Whelan ◽  
Erwin Hack ◽  
Thorsten Siebert ◽  
Richard L. Burguete ◽  
E.A. Patterson ◽  
...  
Keyword(s):  
Strain Measurement ◽  
Parametric Design ◽  
Image Correlation ◽  
Standard Reference Materials ◽  
Full Field ◽  
Measurement Systems ◽  
Measurement Protocol ◽  
Optical Strain Measurement ◽  
Optical Strain ◽  
Point Bend

There are no standard reference materials suitable for the calibration of full-field optical strain measurement systems. This is hindering the uptake of the technology by industrial end-users since optical metrology instrumentation and procedures cannot be easily integrated into quality assurance systems. The EU-funded SPOTS project is developing a physical reference material (PRM) and measurement protocol that should provide the basis of a calibration standard for establishing the traceability of strain values obtained with optical devices. This paper describes a PRM based on a parametric design of monolithic four-point bend test that can reliably generate a known strain field over a range of specimen sizes. Measurements acquired from strain gauges and LVDTs compared well with data obtained from ESPI, digital image correlation, photoelasticity and thermoelasticity studies, demonstrating excellent repeatability and inter-laboratory reproducibility.

scholarly journals Calibration and assessment of full-field optical strain measurement procedures and instrumentation

2006 ◽  
Author(s):  
Malgorzata Kujawinska ◽  
E. A. Patterson ◽  
R. Burguete ◽  
E. Hack ◽  
D. Mendels ◽  
...  
Keyword(s):  
Strain Measurement ◽  
Full Field ◽  
Optical Strain Measurement ◽  
Optical Strain

Development of standard measurement chain for full-field optical strain measurement methods

2004 ◽  
Author(s):  
Leszek Salbut ◽  
Malgorzata Kujawinska ◽  
Eann Patterson ◽  
Erwin Hack ◽  
Richard Burguete ◽  
...  
Keyword(s):  
Strain Measurement ◽  
Measurement Methods ◽  
Full Field ◽  
Standard Measurement ◽  
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.

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