scholarly journals Sensor Integrated Load-Bearing Structures: Measuring Axis Extension with DIC-Based Transducers

Sensors ◽  
2021 ◽  
Vol 21 (12) ◽  
pp. 4104
Author(s):  
Nassr Al-Baradoni ◽  
Peter Groche
Keyword(s):  
Cost Effective ◽  
Image Correlation ◽  
Maximum Deviation ◽  
Single Image ◽  
Eccentric Load ◽  
Load Bearing ◽  
Out Of Plane ◽  
Axis Extension ◽  
Plane Displacement ◽  
Imaging Sensor

In this paper we present a novel, cost-effective camera-based multi-axis force/torque sensor concept for integration into metallic load-bearing structures. A two-part pattern consisting of a directly incident and mirrored light beam is projected onto the imaging sensor surface. This allows the capturing of 3D displacements, occurring due to structure deformation under load in a single image. The displacement of defined features in size and position can be accurately analyzed and determined through digital image correlation (DIC). Validation on a prototype shows good accuracy of the measurement and a unique identification of all in- and out-of-plane displacement components under multiaxial load. Measurements show a maximum deviation related to the maximum measured values between 2.5% and 4.8% for uniaxial loads ( and between 2.5% and 10.43% for combined bending, torsion and axial load. In the course of the investigations, the measurement inaccuracy was partly attributed to the joint used between the sensor parts and the structure as well as to eccentric load.

Using the Simplified 3D DIC Method to Measure the Deformation of 3D Surface

2011 ◽  
Vol 121-126 ◽  
pp. 3945-3949 ◽  
Author(s):  
Shih Heng Tung ◽  
Jui Chao Kuo ◽  
Ming Hsiang Shih ◽  
Wen Pei Sung
Keyword(s):  
Measurement Accuracy ◽  
Good Accuracy ◽  
Correlation Method ◽  
Image Correlation ◽  
2D Digital Image Correlation ◽  
Plate Specimen ◽  
Before And After ◽  
Out Of Plane ◽  
Plane Displacement ◽  
2D And 3D

In recent years, 2D digital image correlation method (DIC) has been widely used in the measurement of plane strain. However, out-of-plane displacement could be induced during the loading and it would affect the measurement accuracy. Thus, a 3D measurement is necessary. This study utilizes a simplified 3D DIC to measure the geometry of an object before and after deformation. Then the finite element concept is involved to determine the strain after deformation. A flat plate specimen with in-plane and out-of-plane displacement is observed. Both 2D and 3D DIC are used to analyze the strain. The results show that using 3D DIC to measure strain is feasible and with a very good accuracy.

scholarly journals Hybrid composite sandwich panels under blast and impact loading

2018 ◽  
Vol 183 ◽  
pp. 02003
Author(s):  
Emily Rolfe ◽  
Hari Arora ◽  
Paul A. Hooper ◽  
John P. Dear
Keyword(s):  
Carbon Fibre ◽  
Glass Fibre ◽  
Blast Loading ◽  
Impact Testing ◽  
Image Correlation ◽  
Small Scale ◽  
Composite Sandwich ◽  
Out Of Plane ◽  
Plane Displacement ◽  
The Impact

Naval vessels may undergo high strain rate loading, including impact, wave slamming and blast loading. Predicting the behaviour of composite sandwich structures to such loading is complicated, hence representative experiments are required. Two panels with hybrid carbon-and glass-fibre skins were fabricated and subjected to full-scale air blast loading. The panels were 1.7 × 1.5 m in size and were subjected to a 100 kg nitromethane charge at a stand-off distance of 15 m. 3D Digital Image Correlation (DIC) was implemented behind each of the panels to record the full-field out-of-plane displacement of the panels. In addition, the panels were instrumented with foil strain gauges on the front skins to record the response of the panel side in contact with the blast. The results revealed that the combination of glass-and carbon-fibre improves the blast resilience when compared to previous blast testing on panels with exclusively glass-fibre or carbon-fibre skins. However, the order in which the glass-and carbon-fibre layers were arranged did not have a significant effect on the overall panel performance. In addition, panels with the same hybrid skins were subjected to high velocity impact testing. An aluminium projectile with 25 mm diameter was fired at small scale panels (160 × 160 mm) using a laboratory gas gun at a velocity of 78 ms−1. 3D DIC was again used to record the out-of-plane displacement of these panels. In contrast to the blast experiment, the impact results showed that the order in which glass-and carbon-fibres were arranged did affect both the out-of-plane displacement and damage to the panels. The least damage occurred when glass-fibre layers were placed on the outermost layers impacted by the projectile.

A Comparison Between the Accuracy of Two-Dimensional and Three-Dimensional Strain Measurements

2018 ◽  
Vol 1 (2) ◽  
Author(s):  
Niranjan Desai ◽  
Joel Poling ◽  
Gregor Fischer ◽  
Christos Georgakis
Keyword(s):  
Structural Damage ◽  
Measurement Techniques ◽  
Three Dimensional ◽  
Image Correlation ◽  
3D Measurement ◽  
Two Dimensional ◽  
Strain Measurements ◽  
Out Of Plane ◽  
2D System ◽  
Plane Displacement

This investigation determined the effect of specimen out-of-plane movement on the accuracy of strain measurement made applying two-dimensional (2D) and three-dimensional (3D) measurement approaches using the representative, state-of-the-art digital image correlation (DIC)-based tool ARAMIS. DIC techniques can be used in structural health monitoring (SHM) by measuring structural strains and correlating them to structural damage. This study was motivated by initially undetected damage at low strains in connections of a real-world bridge, whose detection would have prevented its propagation, resulting in lower repair costs. This study builds upon an initial investigation that concluded that out-of-plane specimen movement results in noise in DIC-based strain measurements. The effect of specimen out-of-plane displacement on the accuracy of strain measurements using the 2D and 3D measurement techniques was determined over a range of strain values and specimen out-of-plane displacements. Based upon the results of this study, the 2D system could measure strains as camera focus was being lost, and the effect of the loss of focus became apparent at 1.0 mm beam out-of-plane displacement while measuring strain of the order of magnitude of approximately 0.12%. The corresponding results for the 3D system demonstrate that the beam out-of-plane displacement begins to affect the accuracy of the strain measurements at approximately 0.025% strain for all magnitudes of out-of-plane displacement, and the 3D ARAMIS system can make accurate strain measurements at up to 2.5 mm amplitude at this strain. Finally, based upon the magnitudes of strain and out-of-plane displacement amplitudes that typically occur in real steel bridges, it is advisable to use the 3D system for SHM of stiff structures instead of the 2D system.

Sign in / Sign up

Export Citation Format

Share Document