Análisis sobre la influencia de la densidad en la termografía de infrarrojos y el alcance de esta técnica en la detección de defectos internos en la madera

C Rodríguez-Liñán,P Rubio-De Hita,F Pérez-Gálvez,M J Morales-Conde

doi:10.3989/mc.2012.62410

Abstract

This paper shows the results of a laboratory phase for the determination of the 1limits of infrared thermography in detecting internal defects in wood and, furthermore, it analyses how the density of this material can influence the surface temperature displayed in a thermogram. To this end, experimental work is carried out whereby a series of work and environmental parameters are monitored (such as environmental temperature, relative humidity, distance to target), and the process is systematized by using pieces of different wood species (different densities) and by devising a set of samples for which various possible cases are analysed in terms of size and internal position of the damage. Similarly, using these samples, a study has been conducted on the effect on the thermal image produced by an increase of humidity inside the defect phenomena normally associated with wood decay.

Highlights

Wood is a material which, owing to its workability and mechanical properties, has been widely used throughout history as a structural material
Pathologies of a biotic origin, such as fungi and social insects, associated with an increase of humidity degrade its structure thereby provoking a loss of density and a decrease in the resistance of the wood
Its role is mainly reserved for the detection of humidity and analysis of the energy performance of buildings and their facilities (1, 2). This technique is used to detect cracks in concrete structures and as a quality control technique for certain materials (3). All this leads us to consider its applicability in the study of wood as a material that is found in rehabilitation work

Summary

Introduction

Wood is a material which, owing to its workability and mechanical properties, has been widely used throughout history as a structural material. Pathologies of a biotic origin, such as fungi and social insects (termites), associated with an increase of humidity degrade its structure thereby provoking a loss of density and a decrease in the resistance of the wood This problem, widespread in ancient structures, together with the need to locate affected areas which have no damage visible on the surface, has led us to experiment with techniques that enable the development of a working methodology to deal with such situations, in order to establish an accurate diagnosis of the state of deterioration of a structure. All this leads us to consider its applicability in the study of wood as a material that is found in rehabilitation work

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