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 >

L. Zhang¹, T. Boulet¹, J. Hein¹, M. Arnoult¹, M. Negahban¹

The International Conference on Computational & Experimental Engineering and Sciences, Vol.15, No.2, pp. 37-46, 2010, DOI:10.3970/icces.2010.015.037

Abstract The modeling of the response of the human head to blast like loading is of importance for many applications including the study of traumatic brain injury resulting from improvised explosive devices. One key issue in simulating the response of the head is to have models that are characteristic of the response of the head and its components under these conditions. We review different characterization efforts for evaluating the response of the skin, skull, and brain within this window of response and use these results to develop models appropriate for the characterization of each component. We discuss efforts made to construct… More >

T. Y. Lin, H. C. Ping, T. Y. Yang, C. T. Chan, C. C. Yang¹

The International Conference on Computational & Experimental Engineering and Sciences, Vol.11, No.4, pp. 115-122, 2009, DOI:10.3970/icces.2009.011.115

Abstract The artillery weapons have been developed from the thirteenth century to the present. Generally, it contains a gun body and a gun mount. The gun body consists of a barrel, a breech, a breechblock, and a muzzle brake. In addition, the gun mount is composed of recoil mechanisms, elevating mechanisms, traversing mechanisms, and supporting parts. Among these parts, the muzzle brake and recoil mechanism can reduce the mass recoil force during firing, and push the gun body back to the original position after firing. Before the mid-nineteenth century, general guns did not assemble any device having the cushioning effect. For… More >

Ji Won Yoon¹, Tae Won Park², Kab Jin Jun³, Soo Ho Lee³, Sung Pil Jung³

The International Conference on Computational & Experimental Engineering and Sciences, Vol.11, No.3, pp. 73-74, 2009, DOI:10.3970/icces.2009.011.073

Abstract Industrial vehicles like forklifts are used in many areas, such as the heavy industries, shipbuilding, and manufacturing industries. Recently, the rise in the oil prices and stricter environmental regulations have created the need for new technologies for industrial vehicles. Presently, the performance of the power train has reached its limit and cannot be further improved without increasing cost, weight and volume. Therefore, a system based on a new paradigm is needed. To achieve this goal, the structure of the power transfer system needs to be revolutionized. First, weight and size need to be reduced. In addition, the number of gears… More >

Y. Bei¹, B.J. Fregly¹, W.G. Sawyer¹, S.A. Banks^1,2, N.H. Kim¹

CMES-Computer Modeling in Engineering & Sciences, Vol.6, No.2, pp. 145-152, 2004, DOI:10.3970/cmes.2004.006.145

Abstract Mild wear of ultra-high molecular weight polyethylene tibial inserts continues to affect the longevity of total knee replacements (TKRs). Using static finite element and elasticity analyses, previous studies have hypothesized that polyethylene wear can be reduced by using a thicker tibial insert to decrease contact pressures. To date, no study has taken this hypothesis to the next step by performing dynamic analyses under in vivo functional conditions to quantify the relationship between contact pressures, insert thickness, and mild wear. This study utilizes multibody dynamic simulations incorporating elastic contact to perform such analyses. \textit {In vivo} fluoroscopic gait data from two… More >

Yixiong Wei¹, Qifu Wang^1,2, Yingjun Wang¹, Yunbao Huang¹

CMES-Computer Modeling in Engineering & Sciences, Vol.86, No.3, pp. 241-274, 2012, DOI:10.3970/cmes.2012.086.241

Abstract In this study, we propose a novel method to accelerate the process of elastodynamic analysis in 3D problems with BEM (boundary element method). With applying the DRBEM (dual reciprocity boundary element method) to form new integral equations for reducing complexity;the modified FMM (fast multipole method)is introduced to simplify the computation process and save storage space by avoiding intermediate coefficientmatrices. At the same time, FMM-DRBEM is reprogrammed in parallel byapplying GPU with CUDA (Compute Unified Device Architecture)for improving efficiency further.The main features in this paper are: ( 1 )with respect to defects of classical method for elastodynamic, modified FMM-DRBEM algorithm is… More >

Jiaoyan Li¹, Xianqiao Wang², James D. Lee¹

CMES-Computer Modeling in Engineering & Sciences, Vol.85, No.5, pp. 463-480, 2012, DOI:10.3970/cmes.2012.085.463

Abstract This paper presents a novel multiple time scale algorithm integrated with the concurrent atomic/atom-based continuum modeling, which involves molecular dynamic (MD) simulation and coarse-grained molecular dynamic (CG-MD) simulation. To capture the key features of the solution region while still considering the computational efficiency, we decompose it into two sub-regions in space and utilize the central difference method with different time steps for different sub-regions to march on in time. Usually, the solution region contains a critical field and a non-critical far field. For the critical field (named atomic region) modeled by MD simulation, a relatively small time step is used… More >

Wenzhong Tang¹, Suresh G. Advani¹

CMES-Computer Modeling in Engineering & Sciences, Vol.25, No.3, pp. 149-164, 2008, DOI:10.3970/cmes.2008.025.149

Abstract In this paper, a method for studying nanotube dynamics in simple shear flow was developed. A nanotube was described as a flexible fiber with a sphere-chain model. The forces on the nanotube were obtained by molecular dynamics simulations. The motion of the nanotube in simple shear flow was tracked by the flexible fiber dynamics method [Tang and Advani (2005)]. The viscosity of dilute nanotube suspensions was calculated based on the nanotube dynamics, and the effects of the aspect ratio and initial curvature of the nanotube on suspension viscosity are explored and discussed. More >

Wenzhong Tang¹, Suresh G. Advani¹

CMES-Computer Modeling in Engineering & Sciences, Vol.8, No.2, pp. 165-176, 2005, DOI:10.3970/cmes.2005.008.165

Abstract An optimization method is proposed to simulate the motion of long flexible fibers in shear flow. The fiber is modeled as spheres connected by massless rigid rods and ball-socket joints. The optimization method is mathematically justified and used to obtain the position of a fiber at the next time step from its current position. Results for a single fiber in simple shear flow agree well with those reported in the literature. The usefulness of the method is demonstrated by simulating the motion of two interactive fibers subjected to shear flow field, and by studying the viscosity of dilute suspensions of… More >

Walter Gerstle¹, Stewart Silling², David Read³, Vinod Tewary⁴, Richard Lehoucq⁵

CMC-Computers, Materials & Continua, Vol.8, No.2, pp. 75-92, 2008, DOI:10.3970/cmc.2008.008.075

Abstract A theoretical framework, based upon the peridynamic model, is presented for analytical and computational simulation of electromigration. The framework allows four coupled physical processes to be modeled simultaneously: mechanical deformation, heat transfer, electrical potential distribution, and vacancy diffusion. The dynamics of void and crack formation, and hillock and whisker growth can potentially be modeled. The framework can potentially be applied at several modeling scales: atomistic, crystallite, multiple crystallite, and macro. The conceptual simplicity of the model promises to permit many phenomena observed in microchips, including electromigration, thermo-mechanical crack formation, and fatigue crack formation, to be analyzed in a systematic and… More >