Gaspar-Peralta P¹, JC Carrillo-Rodríguez¹, JL Chávez-Servia, AM Vera-Guzmán², I Pérez-León¹

Phyton-International Journal of Experimental Botany, Vol.81, pp. 15-22, 2012, DOI:10.32604/phyton.2012.81.015

Abstract In order to evaluate the agronomic behavior, genotypic variation, lycopene content, and other components of fruit quality, eight advanced tomato lines were planted in greenhouses during two crop cycles, August-December 2008 and February-July 2009. Tomato lines showed significant differences in leaf length (LL), stem diameter (SD), number of flowers per branch (FLNB), number of fruits per branch (FRNB), locules per fruit (LPF), and fruit length (FRL), and the greatest phenotypic expression in fruit traits was quantified in August-December 2008. Environmental variance was significantly higher than the genotypic and genotype-environment interaction variances in LL, FRNB, fruits… More >

Urrutia J¹, R Rivera^1,2, E Hauenstein¹, P De los Ríos¹

Phyton-International Journal of Experimental Botany, Vol.81, pp. 7-13, 2012, DOI:10.32604/phyton.2012.81.007

Abstract Macrophytes of inland waters are a group of great biological interest. Although lentic systems are ideal for their growth, their presence is not so evident in oligotrophic water bodies, proliferating largely in areas with some level of contamination. A useful tool to determine the presence of a regulatory factor in the composition of these and other biological communities is the use of null models. This analysis was applied based on the co-occurrence of species through a matrix of presence and absence, with the purpose of determining the presence of randomness in species associations. The three 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 >

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 >