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 >

Smitha Gopinath^1,2, A. Ramachandra Murthy¹, Nagesh R. Iyer¹

Structural Durability & Health Monitoring, Vol.9, No.1, pp. 1-20, 2013, DOI:10.32604/sdhm.2013.009.001

Abstract This paper deals with the performance of concrete specimens confined with different glass fabric reinforcement in organic binder consisting of resins. Three varieties of glass fabrics such as woven roving (WR), chopped strand mat (CSM), and textile reinforcement have been studied in the investigation. Experiments have been conducted on unconfined and confined concrete cylindrical specimens under compression. The effect of number of layers on confinement has been studied for specific cases. Specimens have been tested under displacement control. It is observed from the experiments that there is an increase in load carrying capacity as well More >

F. Balle¹, S. Huxhold¹, G. Wagner¹, D. Eifler¹

Structural Durability & Health Monitoring, Vol.8, No.4, pp. 359-370, 2012, DOI:10.32604/sdhm.2012.008.359

Abstract Aluminum alloys and carbon fiber reinforced polymers (CFRP) are two important materials for lightweight design and the combination of these dissimilar materials becomes increasingly important. Recent investigations have shown that ultrasonic metal welding is a well suited process to realize aluminum/CFRP-joints.The ultrasonic shear oscillation parallel to the welding zone with a simultaneous welding force perpendicular to the aluminum/CFRP-sheets melts the polymer matrix and squeezes the polymer matrix out of the welding zone. This allows a direct contact between the carbon fibers and the aluminum. Beside monotonic properties the cyclic deformation behavior of these ultrasonically welded More >

F. De Angelis¹

Structural Durability & Health Monitoring, Vol.8, No.4, pp. 341-358, 2012, DOI:10.32604/sdhm.2012.008.341

Abstract The influence of different loading rates on the structural response of elasto/viscoplastic materials is illustrated with specific numerical examples. An associated formulation of the evolutive laws in elasto/viscoplasticity is presented within the framework of the generalized standard material model with internal variables. An appropriate solution scheme is applied which is capable to be adopted for different constitutive models. Different loading programs are analyzed by considering different values of the loading rate and of the intrinsic properties of the material. Computational applications and examples are illustrated which describe the rate-dependency of the elasto/viscoplastic material behavior. The More >

L. Solazzi^1,2, C. Petrogalli¹, M. Lancini¹

Structural Durability & Health Monitoring, Vol.8, No.4, pp. 329-340, 2012, DOI:10.32604/sdhm.2012.008.329

Abstract A study on vibrations related to rolling contact fatigue test bench and a possible way to correlate this mechanical behavior and damage of the specimens is presented. In particular it has been evaluated the possibility to detect and quantify, thanks to vibration analysis, the damage on two discs subjected to rolling contact fatigue in different working conditions. Paper is divided in two parts. In the first part there is a description of test bench and results of its static and modal analyses. Then, some tests were carried out changing working conditions and specimens' parameters and More >

C. Colombo¹, E.G. Marchesin¹, L. Vergani^1,2, E. Boccafogli³, G. Verni³

Structural Durability & Health Monitoring, Vol.8, No.4, pp. 307-328, 2012, DOI:10.32604/sdhm.2012.008.307

Abstract In this study an experimental device for testing the structural integrity of lower limb (transtibial and transfemoral) prostheses is proposed and studied, in accordance with the ISO 10328 Standard. Aim of the development of this device is to mechanically test these kinds of prostheses, for claiming the compliance with the standard. In the first part of the paper, experimental setup of the laboratory is described for the different kinds of prescribed tests. In the second part, the test case of a transtibial prosthesis for children is proposed. After verifying the compliance with the standard of More >

S. Kwofie¹

Structural Durability & Health Monitoring, Vol.8, No.4, pp. 295-306, 2012, DOI:10.32604/sdhm.2012.008.295

Abstract Fatigue life of components may be enhanced by mechanical surface treatments, such as shot penning, which induce compressive residual stresses in the component's surface. Under cyclic/fatigue loads, however, relaxation of the residual stress may occur thus, reducing the optimum benefit of the surface treatment. For health monitoring / life prediction under such conditions it is important to be able to assess stress relaxation in real-time. However, the phenomenon of cyclic relaxation of residual stress is not well understood and its tracking during component operation is a technical challenge. By means of cyclic plastic deformation model More >

A. Rama Mohan Rao¹, S. Krishna Kumar¹, K. Lakshmi¹

Structural Durability & Health Monitoring, Vol.8, No.3, pp. 271-294, 2012, DOI:10.32604/sdhm.2012.008.271

Abstract Current advancements in structural health monitoring, sensor and sensor network technologies have encouraged using large number of sensor networks in monitoring spatially large civil structures like bridges. Large amount of spatial information obtained from these sensor networks will enhance the reliability in truly assessing the state of the health of the structure. However, if sensors go faulty during operation, the feature extraction techniques embedded into SHM scheme may lead to an erroneous conclusion and often end up with false alarms. Hence it is highly desirable to robustly detect the faulty sensors, isolate and correct the… More >

Leandro Fleck Fadel Miguel¹, Letícia Fleck Fadel Miguel²

Structural Durability & Health Monitoring, Vol.8, No.3, pp. 249-270, 2012, DOI:10.32604/sdhm.2012.008.249

Abstract Model updating may be defined as an adjustment on the FE model through modal parameters experimentally obtained, in order to better represent its dynamic behavior. From this definition, structural health monitoring (SHM) methods can be considered closely related with these procedures, because it refers to the implementation of in situ non-destructive sensing and analysis of the dynamic system characteristics, which aims to detect changes that could indicate damage. Within this context, the present paper evaluates an iterative model updating approach when it is subjected to experimental vibration data. In addition, after getting the experimental adjusted… More >