R. Afshar¹, F. Berto^1,2

Structural Durability & Health Monitoring, Vol.9, No.4, pp. 349-364, 2013, DOI:10.32604/sdhm.2013.009.349

Abstract Using the finite element method, three-dimensional models of a number of periodic blunt and sharp notches subjected to tension loading are carried out. The aim of this research is to investigate the thickness effect on the location of maximum stress and notch stress intensity factor (NSIF) of corresponding blunt and sharp periodic notches respectively. With this aim, a wide range of notch geometries are examined. While for two-dimensional plates weakened by periodic notches some results are available in the literature, this paper first faces with the problem of three-dimensional cases. The total of about 100 geometrical configurations are investigated.
It… More >

F. Caputo, G. Lamanna, A. De Luca¹, R. Borrelli, S. Franchitti²

Structural Durability & Health Monitoring, Vol.9, No.3, pp. 253-267, 2013, DOI:10.32604/sdhm.2013.009.253

Abstract The aim of the proposed research activity is to investigate on the structural behaviour of laminated composite plates, in order to develop numerical models able to describe their "damage resistance" under low velocity impacts. To achieve these results it is necessary to provide understanding of and ultimately predict the initiation and the progression mechanisms of damage. Since analytical closed-form methods are unable to describe simultaneously different failure modes and experimental testing can give indications only for specific cases, not generally applicable, it is necessary to improve numerical techniques, which on the base of opportunely selected and calibrated models are able… 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 >

Smitha Gopinath¹, J. Rajasankar^1,2, Nagesh R. Iyer¹, T. S. Krishnamoorthy¹, B.H.Bharatkumar¹, N. Lakshmanan¹

Structural Durability & Health Monitoring, Vol.5, No.4, pp. 311-336, 2009, DOI:10.3970/sdhm.2009.005.311

Abstract In this paper, a two-phase strain-based constitutive model is proposed for concrete under tension. First phase deals with modelling uncracked concrete while the behaviour of concrete in cracked condition is modelled in second phase with appropriate theoretical support. A bilinear tension softening curve of concrete defined in crack width-stress space is taken as the basis to propose the model. Smeared representation of reinforcement and cracks along with multi-layered geometry definition of reinforced concrete (RC) structures is used to implement the model. Through this, it is shown that change in the orientation of tensile cracks with increasing load on the structure… More >

A.B. Mahmud Hasan^1,2, M A Wahab¹, S.M. Guo¹

Structural Durability & Health Monitoring, Vol.4, No.4, pp. 231-240, 2008, DOI:10.3970/sdhm.2008.004.231

Abstract This paper presents details analysis of Heat Affected Zone (HAZ) in High Temperature Vacuum Tube Furnace (HTVTF) to predict fracture region in tube wall due to thermal stress from temperature variation across its thickness. A simple mathematical model is used to illustrate stress concentration arising due to thermal stresses in tube wall and HAZs. Finite element model and analysis were carried out utilizing finite element analysis commercial codes. Combination of thermal stress due to temperature difference determine fracture region. Experimental and simulation results of inside temperature of tube are observed and similar relation have been found. Observation of heat affected… More >

M. M. Rahman¹, A. K. Arrifin², M. J. M. Nor², S. Abdullah²

Structural Durability & Health Monitoring, Vol.4, No.3, pp. 173-180, 2008, DOI:10.3970/sdhm.2008.004.173

Abstract This paper presents the fatigue analysis of spot-weld joints for automative structures to predict the lifetime and location of the weakest spot-welds due to the imposed loading conditions. A simple model was used to illustrate the technique of spot-weld fatigue analysis. Finite element model and analysis were carried out utilizing the finite element analysis commercial codes. Linear elastic finite element analysis was carried out to predict the stress state along the weld direction. It can be seen from the results that the predicted life greatly influence the sheet thickness, spot diameter and loading conditions of the model. Acquired results were… More >

Hernández LF^1,2, PM Bellés³, MA Bidegain^4,5, PD Postemsky⁴

Phyton-International Journal of Experimental Botany, Vol.87, pp. 198-208, 2018, DOI:10.32604/phyton.2018.87.198

Abstract Absence or underdevelopment of sunflower fruits come usually from failure in fertilization, stresses as well as physiological and morphological defects in the ovary. Thigmomorphogenesis has never been included as a possible cause. We have previously shown that a 2-3 day fertilization shift can occur between neighboring florets in the sunflower capitulum. It is proposed here that those ovaries with advanced fertilization can generate a significant radial and axial compressive stress on ovaries with delayed fertilization. This mechanical stimulus could be strong enough to trigger a thigmo response that affects further ovary development. In vivo tests were performed, isolating ovaries by… More >

Jianguo Ma^{1, 2}, Changgeng Shuai^{1, 2}, Yan Li^{1, 2}

Sound & Vibration, Vol.52, No.6, pp. 11-17, 2018, DOI:10.32604/sv.2018.03893

Abstract The design and optimization of actuators are difficult and critical for the active-passive hybrid vibration control system. In this paper, an electromagnetic actuator model is established based on Ohm’s Law for magnetic circuit considering the leakage flux. The 600N electromagnetic actuators are designed and optimized based on ANSYS simulation according to the engineering request. Its transient characteristics are studied. The effects of different structural parameters on its output force are analyzed. The experimental results show that the structure parameters and output force characteristics of the designed electromagnetic actuators satisfy the practical requirement. More >

Leone Corradi¹, Francesco Genna²

CMES-Computer Modeling in Engineering & Sciences, Vol.4, No.3&4, pp. 381-396, 2003, DOI:10.3970/cmes.2003.004.381

Abstract A critical comparison of several Finite Element models is presented, with reference to the analysis of the stress and strain states around a tooth or a fixed dental implant. Such an analysis, if performed on a full, three-dimensional geometry of the jaw-tooth/dental implant system, requires significant computational resources, and it is therefore often done on simplified models, whose validity can be questionable. On the other side, the use of simplified models is adequate --- almost mandatory --- when detailed results are needed, or when geometrical and material nonlinearities, as well as other complicating factors, are to be taken into account.… More >

S.H. Ju¹

CMES-Computer Modeling in Engineering & Sciences, Vol.64, No.1, pp. 91-109, 2010, DOI:10.3970/cmes.2010.064.091

Abstract This study develops an OpenMP scheme to parallel the preconditioned conjugate gradient methods (PCG) in shared memory computers. The proposed method is simple and systematic, so a minor change in traditional PCG methods may produce effective parallelism. At first, the global stiffness matrix is re-numbered in order to produce a parallel three-line form matrix, and a subroutine only needs to be called once in the finite element analysis. Several basic OpenMP commands are then added into the traditional incomplete Cholesky factorization (ILU) and symmetric successive over-relaxation (SSOR) codes to make the procedures of matrix multiplication, decomposition, forward substitution, and backward… More >