http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Jie Chen,Yangjun Wu,Limin Zhang,Xiaolong He,Shijie Dong 대한기계학회 2020 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.34 No.5
Under dynamic conditions, the dynamic force between the suspended equipment and the car body is substantially increased. This increase not only affects the ride comfort but also substantially raises the likelihood of fatigue damage to the suspended equipment. A multiobjective analytical target cascading (ATC) optimization is proposed to improve the ride comfort of high-speed trains and reduce the vibration of the suspended equipment. A mathematical simulation model of the vehicle equipment system is established, and the acceleration frequency-response function expression of the car body and the suspension system is obtained. The comfort index of the car body and the acceleration root mean square (RMS) of the suspended equipment are calculated by combining the German vertical irregular track spectrum and the comfort filter function. Meanwhile, the ATC method is used to optimize the car body comfort index and the acceleration RMS of the underframe suspended equipment. Then, the availability of the optimization method is evaluated via numerical simulation. Compared with the original suspension scheme of the underframe equipment, when the running speed of the vehicle is 300 km/h, the RMS value of the vibrational acceleration of the underframe equipment after optimization decreases by 19.9 %, and the ride comfort indexes at the car body center and above the front and rear bogies are improved by 6.4 %, 0.1 %, and 1.1 %, respectively. Simulation results demonstrate that ATC optimization can improve the railway vehicle ride comfort and reduce the vibration of the suspended equipment. This paper provides a new approach to the suspension parameter design of equipment.
Effects of Brain Mechanical Properties on Child Head Responses under Linear Load
Shihai Cui,Yue Chen,Haiyan Li,Lijuan He,Shijie Ruan 대한의용생체공학회 2016 Biomedical Engineering Letters (BMEL) Vol.6 No.2
Purpose It is usually difficult to obtain the accurate mechanicalproperties of pediatric brain and skull because of the absenceof pediatric cadaver experiments. The goal of this work is todiscuss how different brain mechanical properties influencepediatric head response. Methods A validated finite element model of a 3-year-oldchild head with detailed anatomical structures was used toparametrically investigate the effects of mechanical propertieson child head. Taguchi orthogonal method was adopted todecrease the numbers of the simulation under direct impactload. Results With the increase of the skull elastic modulus, thecoup pressure decreases significantly (P < 0.001) whereasthe contrecoup pressure (P < 0.001) and maximum vonMises stress of skull (P < 0.001) increase significantly. Withthe increase of the short-time shear modulus of brain tissue,maximum shear stress of brain tissue (P < 0.001) increasessignificantly whereas the maximum principal strain (P < 0.01)decreases significantly. Conclusions Both Elastic modulus of skull and linearviscoelastic material parameters of brain tissues have statisticallysignificant effects on impact responses of child head. Differentmaterial parameters can lead to a great difference on impactresponses of child head.
Tao Shao,Dehong Bai,Mingzhu Qiu,Yu Li,Qiankun Zhang,Ziyu Xue,Shijie He,Dongxia Zhang,Xibin Zhou 한국공업화학회 2022 Journal of Industrial and Engineering Chemistry Vol.108 No.-
Facile synthesis of more dendritic and uniform Pt-based nanostructures with carbon materials couldgreatly reduce cost and increase Pt utilization for methanol oxidation reaction (MOR) in direct methanolfuel cell (DMFC). This study reports a novel one-pot method to fabricate AgPt nano-pompons (AgPt NPs)with the guidance of N-GQDs through AA reduce the precursor of Ag and Pt. Morphology characterizationdescribes N-GQDs as morphology guiding and dispersing agents to regulate the dendrite formation ofnano-pompons. Under the optimized conditions, the AgPt NPs (Ag1Pt2) display above 11 times improvementin electrocatalytic activity and higher stability for the MOR compared with Pt/C catalysts. Densityfunction theory (DFT) studies prove that the introduction of Ag can greatly enhance the adsorption of COon Pt and promote the transformation of CO to COOH. The facile synthetic method and excellent MORperformance endow AgPt NPs with great application prospect in DMFCs as an anode catalyst.