| 1. |
- Xiao, Sen, et al.
(författare)
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Analysis of chest injury in frontal impact via finite element modelling based on biomechanical experiment
- 2017
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Ingår i: Lixue Xuebao/Chinese Journal of Theoretical and Applied Mechanics. - 0459-1879. ; 49:1, s. 191-201
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Tidskriftsartikel (refereegranskat)abstract
- The usage of the seatbelt as a part of the vehicle protection system has immensely promoted occupant safety. However, recent accident investigation shows that it is necessary to increase the chest injury protective e_ciency in frontal impact condition. This study aims to investigate the influence of seatbelt system design variables on occupant chest injury related physical parameters at varying impact conditions, especially concerning with the chest deflection and distribution of rib stress/strain. The study is conducted by using human body FE model in combination with post mortem human subjects tests. An FE model of the belted occupant is therefore established by using a baseline human body FE model (GHBMC), which is validated according to detailed experimental data regarding kinematics, seatbelt force and chest deflection. A parameter study is implemented in terms of seatbelt position, seatbelt angle and impact speed to determine the influence of seatbelt utilization on occupant thoracic injury in frontal impact. The results show that the influence of seatbelt position on chest deflection and distribution of rib stress/strain is greater than that of the seatbelt angle. Meanwhile, the trends of chest deflections are the same with the trends of the rib stress/strain responses while the changes of seatbelt design variables. This study provides a virtual test method on investigation of the chest injury biomechanics related to the seatbelt design variables. Furthermore, the results from this study of chest injury mechanism will also provide a reference for optimizing of the occupant restraint system. © 2017, Editorial Office of Chinese Journal of Theoretical and Applied Mechanics. All right reserved.
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| 2. |
- Kang, Yachi, 1990-, et al.
(författare)
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Numerical simulation of pressure distribution in bristle seal for turbomachinery
- 2018
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Ingår i: Paiguan Jixie Gongcheng Xuebao/Journal of Drainage and Irrigation Machinery Engineering. - : Editorial Department of Journal of Drainage and Irrigation Machinery Engineering. - 1674-8530. ; 36:5, s. 420-425
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Tidskriftsartikel (refereegranskat)abstract
- In order to further study the pressure distribution in bristle seals, a uniformed two-dimensional closed staggered tube bundle model representing a bristle pack cross-section was proposed and the fluid flow through the bundle was solved by computational fluid dynamics(CFD) method. Accor-ding to the critical Reynolds number for boundary layer transition, a new method was proposed to decide the fluid flow regime in the bundle. The pressure and velocity distributions in the bundle were studied under various pressure differentials across the seal. The influences of distance between bristles and number of circumferential bristle rows on the pressure distribution were tackled. It is shown that the pressure distributions in the uniformed two-dimensional closed staggered tube bundle model agree well with the previous experimental data. The pressure distributions are like "V", while the velocity distributions are like the inverted "V". The pressure borne by the rear 1/3 part of the bristle pack is higher than that by the front 2/3 part. Moreover, the percentage of the pressure differential borne by the last 5 bristle rows increases with increasing total pressure differential. The pressure differential borne by the last bristle row is higher than that by a few rows in front of it. A reduced distance between bristles can allow the pressure to be distributed more even from one row to another. Bristles equally spaced can ensure an even pressure distribution rather well. Increasing the number of rows can also have the same effect. © 2018, Editorial Department of Journal of Drainage and Irrigation Machinery Engineering. All right reserved.
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| 3. |
- Chen, Shuang, et al.
(författare)
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CH4/Air反扩散射流火焰多组分同步PLIF诊断
- 2018
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Ingår i: Shiyan Liuti Lixue/Journal of Experiments in Fluid Mechanics. - 1672-9897. ; 32:1, s. 26-32
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Tidskriftsartikel (refereegranskat)abstract
- The simultaneous multi-species Planar Laser Induced Fluorescence technique plays an important role in studying the flame structure and the two-dimensional distribution of intermediate species in combustion. The experimental system of OH/CH2O/Acetone-PLIF was built in order to study the CH4-Air inverse diffusion jet (IDJ) flame. The system consists of two sets of lasers, two intensifier-CCD cameras, a temporal controller and several lenses. The strategy of fluorescence excitation, the method of synchronous timing control and image calibration procedures are discussed. The IDJ flame was studied using the simultaneous multi-species PLIF technique, and the reaction zone, pre-heating zone and fuel zone of IDJ flame were determined. Experimental results suggest that the IDJ flame is different from either the normal diffusion flame or the premixed jet flame. The behavior of this type of flame reveals similarity to the partially premixed flame. Compared to OH chemilumiscence images, simultaneous multi-species PLIF can provide more detail and information about the flame structure and it has huge potential in fundamental combustion studies and industrial burner experiments
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| 4. |
- Han, Y., et al.
(författare)
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A study on the dynamic responses and injury mechanism of human chest in vehicle-pedestrian collisions
- 2015
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Ingår i: Qiche Gongcheng/Automotive Engineering. - 1000-680X. ; 25:5, s. 516-519, 537
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Tidskriftsartikel (refereegranskat)abstract
- With THUMS pedestrian FE model, simulations on vehicle-pedestrian crash are conducted for four types of vehicles (medium sedan, minicar, van and SUVs) with different front-end structures at a impact speed of 20, 30, 40 and 50km/h to analyze pedestrian chest dynamic response and chest impact conditions as well as the chest deformation modes and injuries of pedestrian including rib deflections. The results demonstrate that the front-end structure of vehicle has significant effects on the dynamic response and chest impact speed of pedestrian and the stiffness distribution of vehicle front-end structure is a major factor affecting the rib deflections and chest deformation mode of pedestrian.
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| 5. |
- Han, Yong, et al.
(författare)
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Finite Element Analysis of Lower Extremity Fractures in Vehicle-Pedestrian Collision
- 2011
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Ingår i: Jilin Daxue Xuebao (Gongxueban)/Journal of Jilin University (Engineering and Technology Edition). - 1671-5497. ; 41:1, s. 6-11，id.1671-5479(2011)01-0006-06-
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Tidskriftsartikel (refereegranskat)abstract
- A finite element Human Body Model (HBM) of lower extremity was improved based on the geometry of human skeleton anatomy. The model consists of the pelvis, the femur, the tibia, the fibula, the patella, the foot bones, primary tendons, knee joint capsule, meniscus, and ligaments. This model is constructed using shell and solid elements also including linear spring-damper elements, it contains of 29777 nodes and 30873 elements. The whole model was validated by comparing the results of simulation with these from shearing-bending cadaver tests described in literature. Then the FE HBM of lower extremity and an existing multi-body system (MBS) human model of the pedestrian were used to reconstruct the real-world vehicle-pedestrian accident and lower limb injuries. Results of injury reconstruction show that this FE model has a good biofidelity and biomechanical response, and can be applied in research on lower limb injury mechanisms and used in the development of injury protective devices.
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| 6. |
- Jia, He, et al.
(författare)
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Optimization and economic analysis of distributed photovoltaic-energy storage system under dynamic electricity price
- 2021
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Ingår i: Taiyangneng Xuebao/Acta Energiae Solaris Sinica. - 0254-0096. ; 42:5, s. 187-193
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Tidskriftsartikel (refereegranskat)abstract
- This paper investigated the influence of different dynamic electricity pricing schemes, energy storage capacity and unit capacity cost on the economics of PV-storage systems. The energy storage control stratety of improving the photovoltaic micro-grid self-consumption was adopted in this study. Taking an office building in Changsha as an example, the dynamic planning method was used to solve the system's best operating strategy and calculated the system' life cycle economy and PV self-consumption rate. The results showed that the system profitable area was increased by 87% for every 41.5% increase of dynamic electricity price. Moreover, the impact of energy storage capacity on system economics is greater than unit cost. The increase of dynamic electricity price is beneficial to increase the self-consumption of photovoltaic power generation, and the storage capacity and unit cost dominate the self-consumption of photovoltaic energy in different intervals.
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| 7. |
- Li, G., et al.
(författare)
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Driver reliance characteristics on forward collision warning systems in adjacent vehicle cut-in situations
- 2020
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Ingår i: Journal of Automotive Safety and Energy. ; 11:1, s. 36-43
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Tidskriftsartikel (refereegranskat)abstract
- An evaluation method was investigated to assess driver reliance characteristics on forward collision warning systems based on a driving simulator to improve driving safety in adjacent vehicle cut-in situations. Using alarm timing (time to collision, TTC) as the control variable, driving behavior data from 12 participants were collected in adjacent vehicle cut-in situations. Two objective indexes (brake reliance index and secondary task index) and two subjective indexes (risk level index and trust level index) were proposed to establish the evaluation system model to realize the quantitative evaluation of driver reliance level on the systems. An L9(34) orthogonal experiment was designed and conducted. Regression models of driver reliance indexes were established. The results show that alarm timing is the most significant factor affecting driver reliance. A late alarm (TTC = 2.4 s) degrades the effectiveness of the systems, while an early alarm (TTC = 1.2 s) causes drivers’ over-reliance on the systems. Therefore, appropriately delaying the alarm timing (TTC = 1.8 s) can improve driver reliance for safety considerations.
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| 8. |
- Li, Huixiong, et al.
(författare)
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蒸汽-冷流体接触冷凝流动的数值模拟
- 2005
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Ingår i: Gongcheng Rewuli Xuebao. - Beijing, China. - 0253-231X. ; 26, s. 963-966
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Tidskriftsartikel (refereegranskat)abstract
- 介绍了关于蒸汽-冷流体直接接触冷凝流动与传热的数值计算模型与部分研究结果。用Level Set方法确定蒸汽-冷流体接触界面的位置和形状,建立了对蒸汽和冷流体普遍适用的动量、能量和质量守恒方程,在能量和质量寺恒方程中增加了部分项用于计算蒸汽冷凝所产生的影响。用有限差分法在交错网格上离散控制方程,用Runge-Kutta法-五阶WENO组合格式求解Level Set输运方程,用压力修正的迭代Projection方法求解动量方程,而用SIMPLE方法求解温度控制方程。对算例的计算结果表明,本文所建立的数值计算模型能反映物理现象的宏观特性。根据计算结果,分析了本文模型的优缺点,并指出了今后改进的方向。
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| 9. |
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| 10. |
- Li, Liangxing, et al.
(författare)
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冷中子源冷包截面含汽率数理模型探讨
- 2005
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Ingår i: Proceedings of the 11<sup>th</sup> Annual Meeting of Chinese Engineering Thermophysics.
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Konferensbidrag (refereegranskat)
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