Experimental techniques in structural Testing: Common Mistakes, how to avoid them and other advice

Abstract

This paper is addressed to research students and academics who are entering or planning to enter experimental structural testing. Following the Dunning–Kruger effect, new researchers to laboratory environments often think that experimental testing is straight forward, and only require specimens to be positioned into the testing machine and loaded. However, if the tests are not carefully planned, safely designed, correctly executed and basic experimental rules followed; the results would be invalid and misleading, and possibly serious injuries could occur. Unfortunately, often these rules cannot be found in textbooks. Therefore, the aim of this paper is to provide guidance on experimental testing of structural systems based on the experience of the authors gained from design and execution of experiments, supervision of research students, mentoring junior colleagues and reviewing experimental research papers. While this paper aims at becoming a reference document to the experimentalists to be, it only focusses on mistakes commonly encountered, provide advice and does not intend to deliver an exhaustive guide on experimental structural testing. It is hoped that this paper will assist researchers in obtaining carefully planned experimental outputs, leading to high-quality research papers. This paper is articulated around three categories: (i) articulating the aims of the experimental tests to be performed, (ii) their execution and (iii) reporting. Accordingly, the testing philosophy in the context of research is discussed to achieve desired outcomes. In terms of execution, common mistakes often seen are described in terms of consistency, preparation, choosing the strain rates, identifying failure modes and accurately assessing the material properties of tested specimens. Solutions are also provided to avoid these mistakes. Finally, advice is provided on the experimental information to be reported in research papers for the readers to trust the investigations and genuinely cite these papers.