Development and validation of a pedestrian deformable finite element model

Tso-Liang Teng,Trung-Kien Le 대한기계학회 2009 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.23 No.8

Pedestrian protection has become an increasingly important consideration in vehicle crash safety. Pedestrian-vehicle crashes cause a significant number of pedestrian fatalities and injuries globally. Computer models are powerful tools for understanding how to reduce the severity of injuries in such crashes. Real-world studies of pedestrians provide an important source of information for evaluating pedestrian model dynamic performance and ability to reconstruct injurycausing events. This study describes the validation process of deformable pedestrian model using published postmortem human subject (PMHS) trajectory and head resultant velocity corridors, and demonstrates its applicability to pedestrian - vehicle impact research. We implemented the deformable pedestrian model using LS-DYNA finite element code. Based on PMHS data, the pedestrian model is used to validate the displacement trajectories of the head, pelvis, knee and foot. The finite element pedestrian model thus obtained can help assess the friendliness of vehicles with pedestrians in traffic crashes and assist in the future development of pedestrian safety technologies.

Bumper shape design for pedestrian safety

Tso-Liang Teng,Cho-Chung Liang,Tuan-Anh Vu 대한기계학회 2016 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.30 No.7

The main cause of leg injuries is the bumper during car-pedestrian accidents. Bumper geometry and bumper material have the greatest effect on pedestrian leg injury. The first objective of this study is to evaluate the effects of bumper shape on pedestrian leg injuries. This study uses three bumper shapes on three car models to evaluate the effects of bumper geometry on pedestrian leg injury: A Ford Taurus, Dodge Intrepid, and Dodge-Neon. Then, based on the results of the impact between legform and bumper, this study chooses the best bumper shape that results in the least injury to the pedestrian’s leg. The second objective of this study is to design a new bumper. Using some conclusions regarding the effects of bumper shape on the pedestrian leg injuries, a new pedestrian-friendly bumper was designed. This bumper satisfies EEVC/WG17 safety requirements regarding pedestrian leg injuries. The analyzed models and results obtained could help evaluate pedestrian friendliness of a vehicle and guide the future designing and development of pedestrian friendly vehicle technologies.

Development and validation of FE models of impactor for pedestrian testing

Tso-Liang Teng,Trong-Hai Nguyen 대한기계학회 2008 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.22 No.9

Car-pedestrian accidents account for a considerable number of automobile accidents in industrialized countries. Safeguarding of pedestrians is taking on an increasingly important role in car design. Working Group 17 (WG17) of the European Enhanced Vehicle-safety Committee (EEVC) proposed four impactor models for assessing pedestrian friendliness of a vehicle. In this study, finite element models of adult headform, child headform, upper legform, and legform impactor of pedestrians were created by using LS-DYNA finite element code. The impactor structures follow the descriptions in the reports of WG17 specifications. Simulated certification tests were performed. Some materials were selected from different trademarks of the same kind of materials. The knee of the legform impactor was designed. The parameters of the springs and dampers were adjusted to satisfy the requirements. Results of simulated certification tests for the four impactors are within WG17 limit ranges. These finite element impactor models obtained herein can help evaluate the pedestrian friendliness of vehicle and guide the future development of pedestrian safety technologies.

DEVELOPMENT AND ANALYSIS OF BUS WITH COMPOSITE-MATERIAL-REINFORCED FRAMES

Tso-Liang Teng,Cho-Chung Liang,Hui-Min Chu 한국자동차공학회 2022 International journal of automotive technology Vol.23 No.5

The bus frame structures suffer serious deformation or fracture and then damage the survival space of passengers. The superstructure of a bus is a frame member that supports the vehicle’s load and incorporates other parts for strength enhancement and impact absorption. Therefore, superstructures of bus play an essential role in protecting passengers in case of rollover accidents. Currently, the frames of large passenger vehicles are mostly manufactured using steel materials. The selection of a composite material that exhibits lightweight and outstanding structural strength has become an imperative topic in research on the reinforcement of large passenger vehicles’ frames. This study examined a vehicle frame reinforced using steel coated with composite materials. According to the relevant regulations in ECE R66 on the superstructure strength of large passenger vehicles, the LS-DYNA simulation was employed to perform structural analysis. A composite-materialreinforced frame was employed to simulate the crush test, thereby evaluating the effect of such reinforcement on enhancing the strength of vehicle frames. Finally, a rollover simulation test was performed according to ECE R66 on a vehicle whose entire frame was constituted by composite-material-reinforced steel. This study’s proposed vehicle frame material for design improvements can serve as references for manufacturers of large passenger vehicle bodies to improve the quality of their product development.

Design of pedestrian friendly vehicle bumper

Tso-Liang Teng,Van-Luc Ngo,Trong-Hai Nguyen 대한기계학회 2010 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.24 No.10

Car-pedestrian accidents take thousands of lives worldwide annually. Therefore, pedestrian protection is an important issue in traffic safety. How to consider a pedestrian friendliness vehicle and then propose pedestrian protection methods are urgent works for minimizing pedestrian injury. For designing a pedestrian friendly vehicle bumper, this study adopts the European Enhanced Vehicle-safety Committee/ Working Group 17 (EEVC/WG17) regulations of legform impactor to bumper tests. Analyzing the pedestrian friendliness of a vehicle bumper by using LS-DYNA is described in detail. Simulation results were analyzed to identify the reasons for the unfriendliness. Furthermore, the analysis of the influence of bumper structure on pedestrian leg was performed and then some guideline was suggested. The analyzed models and results obtained could help evaluate pedestrian friendliness of a vehicle and guide the future development of pedestrian friendly vehicle technologies.

Effect of design parameters on the anti-penetration properties of space armor

Tso-Liang Teng,Ta-Ming Shih,Cheng-Chung Lu 국제구조공학회 2008 Structural Engineering and Mechanics, An Int'l Jou Vol.28 No.6

New types of armor, including space armor, multiple-layered armor, composite armor and modular armor have been successfully developed and installed on the armored vehicles of several nations. The protective capability of armor against penetration is established. Of developed composite armor, space armor has a simple structure and is easy to produce and can be produced at low cost. This study uses the finite element package DYTRAN and the pre and post processor PNTRAN to elucidate the ballistic resistance and penetration of space armor. Factors such as armor thickness, space between armors and projectile profile are considered. A technique for simulating the protection afforded by armor and supporting the design of space armor is developed.

Effect of design parameters on the anti-penetration properties of space armor

Teng, Tso-Liang,Shih, Ta-Ming,Lu, Cheng-Chung Techno-Press 2008 Structural Engineering and Mechanics, An Int'l Jou Vol.28 No.6

New types of armor, including space armor, multiple-layered armor, composite armor and modular armor have been successfully developed and installed on the armored vehicles of several nations. The protective capability of armor against penetration is established. Of developed composite armor, space armor has a simple structure and is easy to produce and can be produced at low cost. This study uses the finite element package DYTRAN and the pre and post processor PNTRAN to elucidate the ballistic resistance and penetration of space armor. Factors such as armor thickness, space between armors and projectile profile are considered. A technique for simulating the protection afforded by armor and supporting the design of space armor is developed.

Low Gate Leakage Current HFET Structure Fabricated by Using a Step-free Airbridge Gate Process

Feng-Tso Chien,Chien-Liang Chan,Chi-Ling Wang,Chien-Nan Liao,Yao-Tsung Tsai,Hsien-Chin Chiu 한국물리학회 2010 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.56 No.3

Conventional heterostructure field-effect transistors (HFETs) have a high gate leakage current due to the gate electrode being in contact with the exposed channel layer and with the carrier-providing layer on the mesa sidewall. In this study, we use a new step-free (SF) air-bridge gate structure to reduce the gate leakage and improve the breakdown voltage. The proposed structure does not increase any MASKs as compared with the conventional process. In addition, this new structure promises a gate-source capacitance smaller than those of conventional heterostructure FET devices. Consequently, the high-frequency performance of the HFETs using the proposed structure can be improved.

Numerical and Experimental Investigations on the Fatigue Life Evaluation of Butt-Welded Joints

Peng Hsiang Chang,Tso Liang Teng 대한금속재료학회 2008 METALS AND MATERIALS International Vol.14 No.3

Effects of Codeine on Esophageal Peristalsis in Patients With Ineffective Esophageal Motility: Studies Using High-resolution Manometry

Wei-Yi Lei,Tso-Tsai Liu,Wei-Chuan Chang,Chih-Hsun Yi,Jui-Sheng Hung,Ming-Wun Wong,Shu-Wei Liang,Lin Lin,Chien-Lin Chen 대한소화기 기능성질환∙운동학회 2024 Journal of Neurogastroenterology and Motility (JNM Vol.30 No.1

Background/AimsThis study aims to evaluate the effects of acute codeine administration on primary and secondary esophageal peristalsis in patients with ineffective esophageal motility (IEM). MethodsEighteen IEM patients (8 women; mean age 37.8 years, range 23-64 years) were enrolled in the study. The patients underwent high-resolution manometry exams, consisting of 10 single wet swallows, multiple rapid swallows, and ten 20 mL rapid air injections to trigger secondary peristalsis. All participants completed 2 separate sessions, including acute administration of codeine (60 mg) and placebo, in a randomized order. ResultsCodeine significantly increased the distal contractile integral (566 ± 81 mmHg∙s∙cm vs 247 ± 36 mmHg∙s∙cm, P = 0.001) and shortened distal latency (5.7 ± 0.2 seconds vs 6.5 ± 0.1 seconds, P < 0.001) for primary peristalsis compared with these parameters after placebo treatment. The mean total break length decreased significantly after codeine treatment compared with the length after placebo (P = 0.003). Codeine significantly increased esophagogastric junction-contractile integral (P = 0.028) but did not change the 4-second integrated relaxation pressure (P = 0.794). Codeine significantly decreased the frequency of weak (P = 0.039) and failed contractions (P = 0.009), resulting in increased frequency of normal primary peristalsis (P < 0.136). No significant differences in the ratio of impaired multiple rapid swallows inhibition and parameters of secondary peristalsis were detected. ConclusionsIn IEM patients, acute administration of codeine increases contraction vigor and reduces distal latency of primary esophageal peristalsis, but has no effect on secondary peristalsis. Future studies are required to further elucidate clinical relevance of these findings, especially in the setting of gastroesophageal reflux disease with IEM.