G. Meneghetti¹

Structural Durability & Health Monitoring, Vol.8, No.2, pp. 111-130, 2012, DOI:10.3970/sdhm.2012.008.111

Abstract This paper deals with the local approach based on the Notch Stress Intensity Factors (NSIFs) to analyse the fatigue behavior of welded joints. In transverse load carrying fillet-welded joints, failure may occur either at the toe or at the root, depending on the geometry. At the toe, due to the flank angles that are usually encountered in practice, mode I local stresses are singular, while mode II stresses are not. Conversely, at the root of the particular joints analysed in the present paper both mode I and mode II stresses are singular and must be taken into account in fatigue… More >

A. Risitano¹, D. Corallo¹, G. Risitano²

Structural Durability & Health Monitoring, Vol.8, No.2, pp. 91-110, 2012, DOI:10.3970/sdhm.2012.008.091

Abstract According to Miner's rule, the fatigue life of a material (or a mechanical component) is not a function of the order of the application of load. Many authors have already observed that the model proposed by Palmgren/Miner leads to underestimation of the damage and one of the reasons could be the disregard of the sequence of loads. Referring to the energy loss related to irreversible damage of the material, it was observed that the Miner's rule gives exact results only if the damage caused by the fatiguing load is low compared to the limit energy of the material. Whereas, if… More >

G. Olmi¹

Structural Durability & Health Monitoring, Vol.8, No.1, pp. 61-90, 2012, DOI:10.3970/sdhm.2012.008.061

Abstract Turbogenerator rotors and coil retaining rings are highly loaded components, under low cycle fatigue at every machine switch on and switch off transient. Their failure during service may lead to very serious consequences. The present paper utilizes several experimental data, concerning the static, cyclic and fatigue behaviour of the rotor material, in order to perform a probabilistic analysis. All the main methodological issues are tackled, consisting in the experimental data processing, in the choice of the random variables that are involved in the fatigue process, in the determination of their distributions, in the practical computation of the probability of failure… More >

F. Curà¹, A. Gallinatti¹, R. Sesana¹

Structural Durability & Health Monitoring, Vol.8, No.1, pp. 45-60, 2012, DOI:10.3970/sdhm.2012.008.045

Abstract In this paper the effect of high cycle fatigue damaging on a commercial steel is investigated by means of experimental measurement of mechanical and dissipative parameters variation during fatigue testing. Experimental procedures for HCF damage incrementing on specimens and for parameter measurement have been defined. A statistical analysis of the significance of the results have been applied to select the parameters which best represent the damage progression on the specimen. More >

F. Berto¹, P. Lazzarin¹, D. Radaj²

Structural Durability & Health Monitoring, Vol.8, No.1, pp. 31-44, 2012, DOI:10.3970/sdhm.2012.008.031

Abstract The fictitious notch rounding concept is applied here for the first time to V-shaped notches with root hole subjected to in-plane shear loading. The fictitious notch radius ρ_f is determined as a function of the real notch radius ρ, the microstructural support length ρ* and the notch opening angle 2α, at first using the normal stress criterion in combination with the maximum tangential stress criterion for finding the crack propagation angle. An analytical method has been developed resulting in closed form expressions for the multiaxiality factor s in the well known relationship ρ_f=ρ+sρ*. It expresses the notch stress averaged over… More >

F. Cianetti¹

Structural Durability & Health Monitoring, Vol.8, No.1, pp. 1-30, 2012, DOI:10.3970/sdhm.2012.008.001

Abstract This research activity refers to the problem of fatigue damage evaluation of mechanical components subjected to random loads. In detail, the present paper describes a procedure, developed by the author, that, starting from component modal modelling, can very quickly gives an answer to the request not only of a qualitative evaluation of its stress state but also of a quantitative and very reliable estimation of the component damage. This estimation is available (both in time and in frequency domain), regardless of the stress state recovery, only by an appropriate elaboration of lagrangian coordinates and elements stress mode shapes. This allows… More >

K.N. Song¹

Structural Durability & Health Monitoring, Vol.7, No.4, pp. 297-306, 2011, DOI:10.3970/sdhm.2011.007.297

Abstract The IHX (Intermediate Heat Exchanger) of a VHTR (Very High Temperature Reactor) transfers 950° heat generated from the VHTR to a hydrogen production plant. The Korea Atomic Energy Research Institute (KAERI) has manufactured a small-scale prototype of a PCHE (Printed Circuit Heat Exchanger) under consideration as a candidate of the IHX. In this study, as a part of high-temperature structural integrity evaluation of the small-scale PCHE prototype, we carried out a macroscopic structural behavior analysis including structural analysis modeling and thermal/elastic structural analysis under small-scale gas loop test conditions as a precedent study to a performance test. The results obtained… More >

F. Caputo, G. Lamanna, A. Soprano¹

Structural Durability & Health Monitoring, Vol.7, No.4, pp. 283-296, 2011, DOI:10.3970/sdhm.2011.007.283

Abstract The present paper deals with a numerical investigation on hybrid bolted joints between unidirectional, quasi isotropic Carbon Fiber Reinforced Polymer (CFRP) composite and aluminium alloy plates, subjected to traction loads. CFRP composite materials are widely used in aerospace applications, where requirements of weight reduction and structural high performances are very compelling. Composite materials generally present high resistance to fatigue and corrosion but the presence of joints in the structure can cause structural problems and then decrease the structural reliability of jointed component.
A hybrid bolted joint constituted of a metal plate, made of aluminium alloy, and a carbon fiber reinforced… More >

Saptarshi Sasmal¹, K. Ramanjaneyulu²

Structural Durability & Health Monitoring, Vol.7, No.4, pp. 253-282, 2011, DOI:10.3970/sdhm.2011.007.253

Abstract This paper proposes a methodology for damage detection in beam like structures using vibration characteristics obtained from transfer matrix technique. At first, vibration characteristics of beam-like structure have been determined with the help of a computer program developed based on the formulations presented in this paper. Then, a detailed study has been carried out to categorise the influence of damage on frequency and mode shape (both displacement and rotational) information. For a structure with known magnitude and location of damage(s), frequencies and mode shape information are obtained and the same has been used in determining the damage in the structure.… More >

Sangoju Bhaskar¹, Ravindra Gettu², B.H. Bharatkumar¹, M. Neelamegam¹

Structural Durability & Health Monitoring, Vol.7, No.4, pp. 231-252, 2011, DOI:10.3970/sdhm.2011.007.231

Abstract The durability of reinforced concrete (RC) exposed to severe environments depends largely on its ability to resist the penetration of aggressive compounds. This paper deals with the corrosion of reinforcement bars (rebars) in cracked concrete exposed to chlorides. A simple U-shaped specimen was used in the study, with a high yield strength deformed bar of 12 mm diameter placed at with 20 mm clear cover. Concrete specimens with three water to cement ratios (w/c) and pre-cracks exposed to chlorides were studied for quality assessment and quantifying the corrosion damage in terms of gravimetric weight loss. Water absorption and rapid chloride… More >