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 significance of the loading program… 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 a procedure that allowed both… 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 the studied prosthesis, values recorded… 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 and the Matlab/Simulink Program cyclic… 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 data, if the data at… 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 model, a numerical damage detection… More >

P.H. Wen¹, M.H. Aliabadi²

Structural Durability & Health Monitoring, Vol.8, No.3, pp. 223-248, 2012, DOI:10.32604/sdhm.2012.008.223

Abstract A mesh-free method for modelling crack growth in functionally graded materials is presented. Based on the variational principle of the potential energy, mesh-free method has been implemented with enriched radial bases interpolation functions to evaluate mixed-mode stress intensity factors, which are introduced to capture the singularity of stress at the crack tip. Paris law and the maximum principle stress criterion are adopted for defining the growth rate and direction of the fatigue crack growth respectively. The accuracy of the proposed method is assessed by comparison to other available solutions. More >

K.N. Song¹

Structural Durability & Health Monitoring, Vol.8, No.3, pp. 209-222, 2012, DOI:10.32604/sdhm.2012.008.209

Abstract A PHE (Process Heat Exchanger) is a key component in transferring the high temperature heat generated from a VHTR (Very High Temperature Reactor) to the chemical reaction for the massive production of hydrogen. A performance test on a small-scale PHE prototype made of Hastelloy-X is currently under way a small-scale gas loop at the Korea Atomic Energy Research Institute. Previous research on the elastic high-temperature structural analysis of the small-scale PHE prototype has been performed using the parent material properties over the whole region. In this study, an elastic-plastic high-temperature structural analysis considering the mechanical properties in the weld-affected zone… More >

He Xufei¹, Deng Zhongmin², Song Zhitao¹

Structural Durability & Health Monitoring, Vol.8, No.3, pp. 193-208, 2012, DOI:10.32604/sdhm.2012.008.193

Abstract This paper describes an information optimizing scheme which is developed by integrating rough set and hierarchical data fusion. The novel structural damage indices are extracted using the information from different sources and then imported into probabilistic neural network (PNN) for classification and health assessment. In order to enhance the accuracy of diagnosis, results from separate PNN classification are fused to achieve comprehensive decision. Rough set is employed to decrease the spatial dimension of data. The predictive accuracy of optimizing scheme is demonstrated on a helicopter, taken as an example, with varied sensors, for multiple damage identification. More >

D. Crivelli¹, M. Guagliano², A. Monici³

Structural Durability & Health Monitoring, Vol.8, No.2, pp. 177-192, 2012, DOI:10.3970/sdhm.2012.008.177

Abstract Pultrusion is a process for manufacturing uniform section composite profiles, which allows to obtain structural elements of virtually any length. The use of E-glass fiber allows to obtain a material with a good rigidity-to-weight and strength-to-weight ratio; these features allowed to use these materials in civil structures, such as poles for anti-noise panels and public lighting, also thanks to their insulating properties. However, the knowledge on the damage development of these materials is still uncertain, and this is slowing down their development.
For these reasons, an experimental study on pultruded materials aimed at identifying the damage modes has been developed.… More >