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The front-end structure crashworthiness design during the conceptual design phase of automobile can shorten production cycle and has a great significance to improve safety. This paper proposes a three-stage target decomposition method to design crash pulse and manage the crash energy absorption of front-end structure of automobile. In this method, the theoretical optimal solution of the Equivalent Dual-trapezia Wave (EDTW) is calculated by the overall layout parameters of automobile and safety requirements of occupant. The optimal EDTW, as the target crash pulse, is decomposed to segments based on the reserved longitudinal crush space and the lateral energy absorption ratio of the front-end substructure. In addition, simple mathematical and mechanical principles are applied to calculate the performance objectives of key energy absorption substructures. Finally, an empirical application of M6 model is conduct to verify the validity of EDTW optimal solution and the realizability of target decomposition. The result shows that this proposed method is effective for the conceptual design of new cars and model change of existing cars. The design process does not rely on large computing software and empirical data and the design result has a guiding role in CAE analysis of automobile safety. [ABSTRACT FROM AUTHOR]

In order to accelerate the optimization process of automotive seats, decrease the amount of computations, and realize forward design of seat performance, a simplified parametric model (SPM) is introduced in this paper during the optimization process of a school bus seat. The validity of the SPM of the seat and the feasibility of the modeling method are proved. The results calculated by the SPM show a good consistency with the shell element model. The SPM can also accurately reflect the deformation and stress of the seat in dynamic tests. Through mechanical analysis and energy analysis of the seat frame, the dynamic performance of the seat is improved to meet regulatory requirements. The SPM has the advantages of simple process, less number of units, time savings in modeling and calculation, and it provides the possibility to quickly analyze the performance of school bus seats and improve seat structure. [ABSTRACT FROM AUTHOR]

Aildenafil, 1-{[3-(6, 7-dihydro-1-methyl-7-oxo-3-propyl-1 H-pyrazolo [4, 3- d] primidin-5-yl)-4-ethoxyphenyl] sulfonyl}- cis-3, 5-dimethylpiperazine, a phosphodiesterase type V enzyme inhibitor (PDE5I), is under development for treatment of erectile dysfunction (ED). The purpose of this study was to elucidate metabolism of aildenafil in vivo in rats and in vitro in mouse, rat, dog, and human liver microsomes. Thirty-one phase I metabolites have been found by LTQ/Orbitrap hybrid mass spectrometry in rat urine, faeces, and bile after oral administration. Major biotransformation pathways of aildenafil included N-dealkylation of the piperazine ring, hydroxylation and dehydrogenation, aliphatic hydroxylation and loss of alkyl group of piperazine ring. Minor pathways involved hydroxylation on the phenyl ring, pyrazole N-demethylation, O-deethylation, loss of piperazine ring (cleavage of N-S bond) and dehydrogenation on the piperazine ring. Similar metabolic pathways of aildenafil were observed in the incubations of liver microsomes from mouse, rat, and dog as well as from human. The depletion rate of parent drug in mouse and rat liver microsomes was significantly different from that in human liver microsomes. The cytochrome P450 reaction phenotyping analysis was conducted using isozyme-specific inhibitors. The results indicated that CYP3A was the main isoenzyme involved in oxidative metabolism of aildenafil. Overall, these in vitro and in vivo findings should provide valuable information on possible metabolic behaviours of aildenafil in humans. Copyright © 2013 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]