A finite element analysis for dynamic strain measurement with enhanced sensitivity

2013 ◽  
Author(s):  
Preeta Sharan ◽  
Raghavendra Mulimani ◽  
Sandip Kumar Roy
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Strain Measurement ◽  
Dynamic Strain ◽  
Element Analysis ◽  
Enhanced Sensitivity

Method for Aortic Wall Strain Measurement With Three-Dimensional Ultrasound Speckle Tracking and Fitted Finite Element Analysis

2013 ◽  
Vol 96 (5) ◽  
pp. 1664-1671 ◽  
Author(s):  
Konstantinos Karatolios ◽  
Andreas Wittek ◽  
Thet Htar Nwe ◽  
Peter Bihari ◽  
Amit Shelke ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Strain Measurement ◽  
Speckle Tracking ◽  
Aortic Wall ◽  
Three Dimensional ◽  
Element Analysis

Investigation of Pipe Strain Measurements in a Curved Wide Plate Specimen

2010 ◽  
Author(s):  
Stijn Hertele´ ◽  
Wim De Waele ◽  
Rudi Denys ◽  
Jeroen Van Wittenberghe ◽  
Matthias Verstraete
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Strain Measurement ◽  
Entire Range ◽  
Experimental Setup ◽  
Element Analysis ◽  
Widespread Application ◽  
Strain Measurements ◽  
Plate Specimen ◽  
Girth Welds

Throughout the last two decades, curved wide plate (CWP) tests have proven to be highly valuable to evaluate the strain capacity of defected girth welds. Despite its widespread application, the CWP test is not yet standardized. In particular, the effects of specimen geometry and deformation measurement setup on the measurement of pipe (remote) strain have not yet been thoroughly documented. Recently, Laboratory Soete published its ‘UGent’ guidelines for CWP testing, in which advice is given on the entire experimental setup. This paper elaborates a finite element analysis of the effect of the CWP specimen’s geometry on the strain measurement. It is found that, following the UGent guidelines and under the assumptions of the study, the geometry has a limited influence for the entire range of investigated materials and pipe dimensions. This indicates that meeting the UGent guidelines for CWP testing yields representative pipe strain measurements.

scholarly journals The Analysis and Resolution of a Fatigue Failure of a Low Pressure Turbine Blade Caused by the Excitation of a Bladed Disc Mode of Vibration

1997 ◽  
Author(s):  
Malcolm C. Staddon ◽  
Paul R. Box ◽  
Barry Barnett ◽  
Tony Horton ◽  
Geoff H. Ballans
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Turbine Blade ◽  
Fatigue Failure ◽  
Strain Gauge ◽  
High Frequency ◽  
Low Pressure ◽  
Dynamic Strain ◽  
Element Analysis ◽  
Low Pressure Turbine

A high cycle fatigue failure of a low pressure turbine blade was investigated. Strain gauge tests of a running engine indicated a high dynamic response of the blade at the nozzle passing frequency. This could be attributed to the excitation of a bladed disc mode of vibration. A Finite Element analysis of the low pressure turbine blades and discs, together with bench testing of the complete structure, confirmed the existence of a high frequency 2nd Nodal Diameter mode of vibration. The levels of dynamic strain determined through strain gauge tests were found to be sufficient enough to explain the failure at the given location. Having understood the problem, the situation was resolved through the use of Finite Element analysis with a short term modification to the original blade aerofoil to prevent the mode from being excited. An aero/mechanical re-design of both the low pressure turbine rotor and the stator was undertaken to resolve the problem by both returning the blade to avoid high frequency excitation, and also by reducing the forcing effect of the nozzle passing frequency. The new design has been validated through strain gauge tests and endurance tests. A further improvement in performance was also obtained.

scholarly journals Accuracy of strain measurement systems on a non-isotropic material and its uncertainty on finite element analysis

2020 ◽  
pp. 030932472092458
Author(s):  
Alessandro Baldassarre ◽  
Juan Ocampo ◽  
Marcias Martinez ◽  
Calvin Rans
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Strain Measurement ◽  
Distributed Sensing ◽  
Image Correlation ◽  
Strain Gauges ◽  
Element Analysis ◽  
Sensing System ◽  
Percentage Difference ◽  
The Finite Element Analysis

The application of strain gauges as recommended by the ASTM standards provides accurate strain measurements in isotropic materials. However, their use in composite materials becomes more challenging due to their anisotropic nature. In this study, we hypothesized that the use of the distributed sensing system and the three-dimensional digital image correlation, which can average strain along a line and surface, respectively, may account for strain variability in composite materials. This study shows an investigation on the mechanical properties of unidirectional, cross-ply, and angle-ply carbon-epoxy specimens using strain gauges, distributed sensing system, and digital image correlation. The Bhattacharyya distance method was used to provide a preliminary evaluation of the closeness of the three different measurement techniques while the B-basis statistical method was used to analyze the experimental data in order to obtain a more conservative and reliable material parameter compared to the conventional averaged value, recommended by ASTM standards. Finally, a finite element model was created in Ansys Workbench™ as a means of evaluating the implication of a single point strain gauges measurement, versus a line or a surface strain measurement. The finite element analysis investigation was performed at a laminae level using the measured experimental elastic modulus and at a lamina–lamina level in which the elastic modulus of the unidirectional case was used as input in all the laminate configurations. The former analysis showed good agreement between the finite element analysis and all the strain measurement systems with an averaged percentage difference below 5%. The latter analysis showed a higher discrepancy in the measured percentage difference. A comparison between the finite element analysis and the strain gauges measurements showed an overall percentage difference between the range of 10% and 26%. Distributed sensing system and three-dimensional digital image correlation measurements provided an overall percentage difference below 10% for all the specimen configurations with a maximum percentage difference recorded for the longitudinal angle-ply case of approximately 9%.

Study on the Pin-Load Distribution of Multiple-Bolted Composite to Metal Joints

2012 ◽  
Vol 525-526 ◽  
pp. 285-288 ◽  
Author(s):  
Xiang Dong Liu ◽  
Ya Zhi Li ◽  
Zhen Hua Yao ◽  
Huai Shu
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Strain Measurement ◽  
Load Distribution ◽  
Lap Joints ◽  
Strain Gages ◽  
Element Analysis ◽  
Single Lap Joints ◽  
Sheet Surface ◽  
The Finite Element Analysis

The experiment and finite element analysis were made to determine the pin-load distribution of multiple countersunk bolted single-lap joints. In the experiment, the pin-load fractions were evaluated indirectly by the lap-sheet surface strains collected from a few rows of strain gages. The joint strains and pin-load distribution were also obtained directly in the finite element analysis. The calculated strains correlated well with the experiment. Nevertheless, the pin-load fraction results of the both techniques are quite different. The further analysis revealed that the procedure of transforming the measured strains into pin loads is not reliable, since the intrinsic additional bending had not been taken into account. Therefore the appropriate way to determine the pin-load distribution should be the numerical analysis validated by the strain measurement. The another attempt showed that the pin-load distribution can be evaluated by the finite element modeling of two-dimensional shells and beams as well with satisfied accuracy.

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