Multi-type Sensor Placement Design for Damage Detection

During the past years, much attention has been drawn on damage detection techniques which play an important role in Structural Health Monitoring Systems [1]. Because damage detection is a kind of inverse problem, it is usually ill-posed. That means small measurement noises could lead to severe detection errors if the measuring system and damage detection algorithms were not properly designed. To improve the well-posedness of damage detection procedure, at least two approaches have been tried: one is using a priori information to regularize the procedure [2]; another is carefully designing the layout of sensors [3]. This paper focuses on the second approach. So far, many methods have been proposed to find the optimal sensor placement [4]. These methods usually consist of a criterion of the optimality and a combinatorial optimization algorithm. Most popular criteria are more or less related to certain properties of Fisher Information Matrix. Based on these criteria, simple heuristics as well as modern meta-heuristics, e.g., Generic Algorithm etc., have been adopted to find the ’optimal’ sensor placement. Although many researches have been conducted in this field, most of them discuss only the optimal number and location of mono-type sensors. But in engineering, multi-type sensors are commonly used to measure different kinds of variables. Based on the well-posedness analysis, this paper proposes a new criterion of the optimal placement for different type of sensors. A new heuristic is also developed to search for good results. Moreover, Monte Carlo simulation is suggested to design a robust damage detection system which contains certain redundancies. The validity of these methods is illustrated by academic as well as engineering examples.