To read this content please select one of the options below:

Temperature profiles obtained in thermoelastic stress test for different frequencies

António José Ramos Silva (Faculty of Engineering, University of Porto, Porto, Portugal) (Instituto de Ciência e Inovação em Engenharia Mecânica e Engenharia Industrial (INEGI), Porto, Portugal)
P.M.G. Moreira (LOME, INEGI, Porto, Portugal)
Mario A.P. Vaz (LOME, INEGI, Porto, Portugal)
Joaquim Gabriel (Faculty of Engineering, University of Porto, Porto, Portugal)

International Journal of Structural Integrity

ISSN: 1757-9864

Article publication date: 6 February 2017

466

Abstract

Purpose

Maintenance is one of the most critical and expensive operations during the life cycle of metallic structures, in particular in the aeronautic industry. However, early detection of fatigue cracks is one of the most demanding operations in global maintenance procedures. In this context, non-destructive testing using image techniques may represent one of the best solutions in such situations, especially thermal stress analyses (TSA) using infrared thermography. The purpose of this paper is to access and characterize the main stress profile calculated through temperature variation, for different load frequencies.

Design/methodology/approach

In this paper, a cyclic load is applied to an aluminum sample component while infrared thermal image is being acquired. According to the literature and experiments, a cyclic load applied to a material results in cyclic temperature variation.

Findings

Frequency has been shown to be an important parameter in TSA evaluations, increasing the measured stress profile amplitude. The loading stimulation frequency and the maximum stress recorded show a good correlation (R2 higher than 0.995). It was verified that further tests and modeling should be performed to fully comprehend the influence of load frequency and to create a standard to conduct thermal stress tests.

Originality/value

This work revealed that the current infrared technology is capable of reaching far more detailed thermal and spatial resolution than the one used in the development of TSA models. Thus, for the first time the influence of mechanical load frequency in the thermal profiles of TSA is visible and consequentially the measured mechanical stress.

Keywords

Acknowledgements

The authors would like to thank the program NORTE-07-0124-FEDER-000035, POPH (Programa Operacional Potencial Humano), QREN (Quadro de Referência Estratégico Nacional) – Tipologia 4.2 promotion of scientific employment funded by the European Social Fund (ESF), and Ministério da Ciência, Tecnologia e Ensino Superior (MCTES). The authors also acknowledge the support of FCT through project grant PTDC/EME-TME/120331/2010 – combined experimental–numerical methodology for SIF determination.

Citation

Silva, A.J.R., Moreira, P.M.G., Vaz, M.A.P. and Gabriel, J. (2017), "Temperature profiles obtained in thermoelastic stress test for different frequencies", International Journal of Structural Integrity, Vol. 8 No. 1, pp. 51-62. https://doi.org/10.1108/IJSI-04-2016-0016

Publisher

:

Emerald Publishing Limited

Copyright © 2017, Emerald Publishing Limited

Related articles