Amafabia, Daerefa-a Mitsheal¹, Montalvão, Diogo², David-West, Opukuro¹, Haritos, George¹

Structural Durability & Health Monitoring, Vol.11, No.2, pp. 91-147, 2017, DOI:10.3970/sdhm.2017.011.091

Abstract Structural Health Monitoring (SHM) is the process of collecting, interpreting and analysing data from structures in order to determine its health status and the remaining life span. Composite materials have been extensively use in recent years in several industries with the aim at reducing the total weight of structures while improving their mechanical properties. However, composite materials are prone to develop damage when subjected to low to medium impacts (i.e. 1-10 m/s and 11-30 m/s respectively). Hence, the need to use SHM techniques to detect damage at the incipient initiation in composite materials is of high importance. Despite the availability… More >

P. Gayathri¹, R. Ganguli^1,2

Structural Durability & Health Monitoring, Vol.7, No.1&2, pp. 119-138, 2011, DOI:10.3970/sdhm.2011.007.119

Abstract The effect of random variation in composite material properties on the reliability of structural damage detection is addressed in this paper. A composite plate is considered as the structure and a finite element model is used for the simulation. Damage growth due to cyclic loading is addressed. Matrix crack induced delamination is emphasized in this paper. Thresholds for the damage accumulation are found using finite element simulations so that the structure can be subjected to inspections and removed from service safely. Uncertainty effects of composite material properties on the response of the structure are quantified using Monte Carlo simulations. Vibration… More >

A. Riccio¹, M. Zarrelli², F. Caputo¹

Structural Durability & Health Monitoring, Vol.9, No.1, pp. 21-42, 2013, DOI:10.32604/sdhm.2013.009.021

Abstract In the present paper a three-dimensional Progressive Damage Approach (PDA) for laminated composites will be presented. This approach is based on the use of a progressive damage finite element with the geometrically non-linear finite element formulation for stress calculation. The FEM element has been integrated with Hashin's failure criteria to split fibre and matrix failure modes and to simulate stiffness degradation within each ply by means of the Ply Discount Method (PDM). FEM code previsions, in the case of complex structures with different mesh densities and element types, were compared with the results obtained using embedded global-local approach to prove… More >

Shu Minakuchi¹, Tadahito Mizutani¹, Haruka Tsukamoto², Mayuko Nishio², Yoji Okabe³, Nobuo Takeda¹

Structural Durability & Health Monitoring, Vol.4, No.4, pp. 199-220, 2008, DOI:10.3970/sdhm.2008.004.199

Abstract The authors propose a technique to detect centimeter internal damages in large-scale composite structures, using an optical fiber network running throughout the structure. A Brillouin-based distributed strain sensing system with centimeter-order spatial resolution (pre-pump pulse Brillouin optical time domain analysis (PPP-BOTDA)) was utilized to detect residual non-uniform strain in the damaged area. First, Brillouin spectral response depending on the strain profile within the spatial resolution was revealed. The spectral response depending on strain non-uniformity was experimentally quantified with consideration of the general characteristics of the Brillouin gain spectrum. Then, the damage detection procedure was proposed, based on the spectral response.… More >

Raimund Rolfes, Steffen Czichon, Benedikt Kriegesmann, Heiko Kruger, Matthias Vogler, Eelco Jansen

The International Conference on Computational & Experimental Engineering and Sciences, Vol.16, No.3, pp. 69-70, 2011, DOI:10.3970/icces.2011.016.069

Abstract Recent work carried out at the Institute of Structural Analysis of the Leibniz University Hannover in the field of composite materials and composite structures is presented. Analysis tools for composite materials and structures are under development, which enable a robust and cost efficient design. Three key areas for design and analysis of composite structures will be covered in the presentation, namely strength, stability, and fatigue analysis.
Predicting the material properties of imperfect composite structures with manufacturing defects such as waviness defects or porosities is still an open challenge. Several analytical approaches exist to determine the reduction of elastic properties… More >

Richard Degenhardt^{1, 2}

The International Conference on Computational & Experimental Engineering and Sciences, Vol.13, No.2, pp. 31-32, 2009, DOI:10.3970/icces.2009.013.031

Abstract This article has no abstract. More >

Raimund Rolfes, Matthias Vogler, Benedikt Kriegesmann¹

The International Conference on Computational & Experimental Engineering and Sciences, Vol.12, No.2, pp. 43-44, 2009, DOI:10.3970/icces.2009.012.043

Abstract Fiber composite structures are usually thin-walled and hence, prone to buckling. Thus, beside material failure also stability problems have to be considered.

Thin-walled cylindrical composite shells buckle in the elastic region and thus, there is no need to consider material non-linearities or material failure. Never the less, a robust design guide for composite shells does not exist until today. The most frequently guideline is NASA SP-8007, which gives an empirical based knockdown factor. Because this guideline is not intended for composite shells and it turned out to be very conservative in numerous cases several approaches have been developed to… More >

Alaimo A.¹, Milazzo A.¹, Orlando C.¹

The International Conference on Computational & Experimental Engineering and Sciences, Vol.11, No.1, pp. 9-16, 2009, DOI:10.3970/icces.2009.011.009

Abstract The main target of the present paper is the analysis of the fracture mechanics behavior of delaminated composite structures actively repaired through piezoelectric patches. The aim at issue has been achieved by using a boundary element code implemented to study piezoelectric solids, including, as limiting case, the applicability to linear elastic anisotropic materials. The assembled structures, made up of the damaged composite components and the piezoelectric patches, have been modeled through the multidomain technique. To take into account for the adhesive layer among the host structure and the active patch, an interface spring-model has been also implemented. The multidomain technique… More >

O. Oyekoya, D. Mba¹, A. El-Zafrany

The International Conference on Computational & Experimental Engineering and Sciences, Vol.6, No.2, pp. 113-118, 2008, DOI:10.3970/icces.2008.006.113

Abstract In this paper, two new Mindlin-type plate bending elements have been derived for the modelling of functionally graded plate subjected to various loading conditions such as tensile loading, in-plane bending and out-of-plane bending. The properties of the first Mindlin-type element (i.e. Average Mindlin element) are computed by using an average fibre distribution technique which averages the macro-mechanical properties over each element. The properties of the second Mindlin-type element (i.e. Smooth Mindlin element) are computed by using a smooth fibre distribution technique, which directly uses the macro-mechanical properties at Gaussian quadrature points of each element. There were two types of non-linearity… More >

Christos C. Chamis¹

The International Conference on Computational & Experimental Engineering and Sciences, Vol.4, No.2, pp. 59-66, 2007, DOI:10.3970/icces.2007.004.059

Abstract A formal procedure for the probabilistic design evaluation of a composite structure is described. The uncertainties in all aspects of a composite structure (constituent material properties, fabrication variables, structural geometry, and service environments, etc.), which result in the uncertain behavior in the composite structural responses, are included in the evaluation. The probabilistic evaluation consists of: (1) design criteria, (2) modeling of composite structures and uncertainties, (3) simulation methods, and (4) the decision-making process. A sample case is presented to illustrate the formal procedure and to demonstrate that composite structural designs can be probabilistically evaluated with accuracy and efficiency. More >