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

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.

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Recent Developments in ARCMAC and Related Creep Strain Monitoring Techniques

ASME 2011 Pressure Vessels and Piping Conference: Volume 7 ◽

10.1115/pvp2011-57948 ◽

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.

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

Volume 1A: 38th Computers and Information in Engineering Conference ◽

10.1115/detc2018-86017 ◽

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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Advanced measurement techniques for braided composite structures: A review of current and upcoming trends

Journal of Composite Materials ◽

10.1177/0021998320903105 ◽

2020 ◽

Vol 54 (25) ◽

pp. 3895-3917 ◽

Cited By ~ 1

Author(s):

Garrett W Melenka ◽

Cagri Ayranci

Keyword(s):

Computed Tomography ◽

Strain Measurement ◽

Composite Structures ◽

Measurement Methods ◽

Micro Computed Tomography ◽

Braided Composites ◽

Optical Strain Measurement ◽

In Situ Strain Measurement ◽

Optical Strain

Braiding is an advanced textile manufacturing method that is used to produce two-dimensional and three-dimensional components. Unlike laminated structures, braids have interlaced yarns that form a continuity between layers. This structure allows for improved impact resistance, damage tolerance, and improved through-thickness reinforcement. Despite the numerous advantages of braided composites, braids also have shortcomings. Their highly complex fiber architecture presents challenges in the availability and choice of the strain measuring and characterization techniques. Advanced measurement methods such as optical strain measurement, micro-computed tomography, and in situ strain measurement are required. Optical strain measurement methods such as digital image correlation and high-speed imaging are necessary to accurately measure the complex deformation and failure that braided composites exhibit. X-ray-based micro-computed tomography measurements can provide detailed geometric and morphologic information for braided structures, which is necessary for accurately predicting the mechanical properties of braided structures. Finally, in situ strain measurement methods will provide detailed information on the internal deformation and strain that exists within braided structures. In situ sensors will also allow for in-service health monitoring of braided structures. This paper provides a detailed review of the aforementioned sensing technologies and their relation to the measurement of braided composite structures.

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Full-field optical strain measurement having postrecording sensitivity and direction selectivity

Experimental Mechanics ◽

10.1007/bf02324500 ◽

1978 ◽

Vol 18 (2) ◽

pp. 56-60 ◽

Cited By ~ 20

Author(s):

Y. Y. Hung ◽

I. M. Daniel ◽

R. E. Rowlands

Keyword(s):

Strain Measurement ◽

Direction Selectivity ◽

Full Field ◽

Optical Strain Measurement ◽

Optical Strain

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On the Calibration of Optical Full-Field Strain Measurement Systems

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.3-4.397 ◽

2006 ◽

Vol 3-4 ◽

pp. 397-402 ◽

Cited By ~ 4

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.

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