F. Caputo¹, G. Lamanna¹, A. Soprano¹

Structural Durability & Health Monitoring, Vol.9, No.3, pp. 217-232, 2013, DOI:10.32604/sdhm.2013.009.217

Abstract In recent years, the study of the behaviour of damaged structures has been focusing on cracked components in presence of an extensive material yielding at the crack tip; under this condition, linear elastic fracture mechanics theory is not able to describe the real stress-strain state at the crack tip and consequently either the static or the fatigue behaviour of the component. In this work, an extensive parametric numerical analysis of the plastic zone size and shape at the crack tip for a through cracked plate under Mode I loading condition is presented. The obtained results More >

D. Schleh¹, D. Liu¹

Structural Durability & Health Monitoring, Vol.9, No.3, pp. 201-216, 2013, DOI:10.32604/sdhm.2013.009.201

Abstract Understanding the response of composite materials to dynamic loading is necessary for their safe and efficient application to many of the world’s engineering designs where stiffness-to-weight ratios are vitally important. In this study, fringe projection was used and evaluated as means to measure the out-of-plane displacement of composite materials from impact loading involving a projectile accelerated horizontally through the use of gas. The capability of providing out-ofplane deformation measurements can largely enrich the investigation of composite materials under horizontal impact which are commonly performed without any measurement other than projectile velocity. The out-of-plane displacement history More >

C. Mapelli¹, A. Manes^1,2, M. Giglio¹, D. Mombelli¹

Structural Durability & Health Monitoring, Vol.9, No.2, pp. 181-199, 2013, DOI:10.32604/sdhm.2013.009.181

Abstract The definition of a complex operative scenario like ballistic damage, that introduces large strains and failure, is a current challenge in the design of critical mechanical components. Aerospace, automotive and manufacturing industries have recently increased their interest in numerical simulations with the long term aim to make these approaches not only reliable enough to reproduce the experimental results but also to provide a trustworthy and effective tool for design. To achieve this aim, the knowledge and calibration of material behaviour is required. Starting from a previous characterization of the constitutive law and ductile failure criterion More >

R. Afshar¹, F. Berto¹

Structural Durability & Health Monitoring, Vol.9, No.2, pp. 167-180, 2013, DOI:10.32604/sdhm.2013.009.167

Abstract In this study, the main advantages of the strain energy density (SED) approach and some recent applications of the SED to the fatigue analysis of welded joints are reviewed. In addition, the paper investigates the scale effect in the threaded plates with sharp notches subjected to tension loading. Some closed form expressions for evaluation of the notch stress intensity factors (NSIFs) of periodic sharp notches, obtained by SED approach, are employed. The new expressions are applicable to narrow notches when the ratio between the notch depth and the plate width, t/W, is lower than 0.025 More >

G. Savaidis¹, M. Malikoutsakis¹, A. Jagenbrein², A. Savaidis³, M. Soare⁴, M.V. Predoi⁴, A. Soare⁴, I.C. Diba⁴

Structural Durability & Health Monitoring, Vol.9, No.2, pp. 129-154, 2013, DOI:10.32604/sdhm.2013.009.129

Abstract Development of corrosion or/and fatigue crack propagation are the most common causes of structural degradation in road and railway tank vessels. An acoustic emission based monitoring procedure in conjunction with follow-up nondestructive testing is here proposed as a promising alternative to the conventional inspection processes enabling continuous health monitoring of the tank structures. Thereby, finite element analysis taking the respective ADR and RID tank design loads into account is proposed as a capable tool to be applied in early stages of development to reveal the hot spot areas, where acoustic emission sensors have to be More >

A. Rama Mohan Rao¹, K. Lakshmi¹, Karthik Ganesan²

Structural Durability & Health Monitoring, Vol.9, No.2, pp. 99-128, 2013, DOI:10.32604/sdhm.2013.009.099

Abstract Development of efficient system identification techniques is highly relevant for large civil infrastructure for effective health monitoring, damage detection and vibration control. This paper presents a system identification scheme in time domain to estimate stiffness and damping parameters of structures using measured acceleration. Instead of solving the system identification problem as an inverse problem, we formulate it as an optimisation problem. Particle swarm optimisation (PSO) and its other variants has been a subject of research for the past few decades for solving complex optimisation problems. In this paper, a dynamic quantum behaved particle swarm optimisation… More >

Ramana M. Pidaparti¹, Alex C. Johnson¹

Structural Durability & Health Monitoring, Vol.9, No.1, pp. 87-98, 2013, DOI:10.32604/sdhm.2013.009.087

Abstract Surface damage in the form of pitting was observed in NiAl Bronze metal subjected to corrosion and cyclic stresses. In order to investigate the stresses surrounding the evolving pits due to corrosion, an image based computational study was carried out. The computational study involves developing an analysis model from the SEM images of corroded pits and then conducting stress analysis. Several computational simulations were carried out with increasing/evolving pits and the corresponding stress environment was obtained. The results obtained indicate that pit profiles (size and height) greatly affect the stress environment and the maximum stresses More >

G. Sarangapani¹, Ranjan Ganguli²

Structural Durability & Health Monitoring, Vol.9, No.1, pp. 67-86, 2013, DOI:10.32604/sdhm.2013.009.067

Abstract Two traditional layups built from 0°/45°/90° plies and two recently proposed alternative non-traditional layups built from 5° /65° plies are analyzed in this paper. It was recently shown experimentally that using such off-axis plies in a composite laminate will result in a more damage tolerant structure. A cantilever beam with two traditional layup composite laminates and two non-traditional layup composite laminates is considered in this paper. Both traditional and non-traditional layup schemes are chosen such that they are "hard" laminates, i.e, much stiffer in the longitudinal direction than the lateral direction. The damage is simulated More >

A. Riccio¹, F. Caputo¹, N. Tessitore²

Structural Durability & Health Monitoring, Vol.9, No.1, pp. 43-66, 2013, DOI:10.32604/sdhm.2013.009.043

Abstract In this paper the mechanical behavior of composites grid structures has been numerically investigated. The evolution of fibers and matrix cracking has been simulated by adopting a progressive damage approach. The Hashin failure criteria and ply properties degradation rules have been adopted to simulate the degradation at ply level. Non-linear analyses on a Representative Volume Element of the composite grid structure have been performed to account for its compression behavior. 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 More >