汽車側(cè)面碰撞乘員生物力學(xué)響應(yīng)與損傷評價研究

1、博士學(xué)位論文汽車側(cè)面碰撞乘員生物力學(xué)響應(yīng)與損傷評價研究作學(xué)指所者科導(dǎo)在姓專教學(xué)名 業(yè) 師 馬正偉 車輛工程 陳吉清 教授 院 機(jī)械與汽車工程學(xué)院2015年7月 論文提交日期 Study on the Biomechanical Responses and InjuryAssessment of the Occupant in Automobile Side ImpactsA Dissertation Submitted for the Degree of Doctor of PhilosophyCandidate ：Ma ZhengweiSupervisor ：Prof. Chen Jiqin

2、gSouth China University of TechnologyGuangzhou, China 摘 要汽車產(chǎn)品在為人類社會提供便利的同時，伴隨發(fā)生的汽車碰撞事故也造成了大量的人員傷亡和財產(chǎn)損失。根據(jù)世界衛(wèi)生組織最近一次的數(shù)據(jù)統(tǒng)計，全球每年有120多萬人死于道路交通事故，有2000-5000萬人在事故中受到傷害，造成的經(jīng)濟(jì)損失達(dá)5000多億美元。側(cè)面碰撞是汽車碰撞事故中一種十分常見并且非常危險的事故形式。相比正面碰撞，側(cè)面碰撞由于結(jié)構(gòu)強(qiáng)度薄弱、吸能部件較少，并且車門與乘員之間距離有限，更容易造成嚴(yán)重的乘員傷亡。汽車碰撞安全研究的目的是為了保證人的安全，汽車碰撞安全性能的高低也主要通過

3、碰撞過程中乘員的傷害程度來評價。因此，深入研究側(cè)面碰撞過程中人體各個部位的生物力學(xué)響應(yīng)、損傷機(jī)理以及損傷耐受限度，對于指導(dǎo)汽車結(jié)構(gòu)安全設(shè)計，改進(jìn)汽車碰撞安全評價標(biāo)準(zhǔn)，以及提高側(cè)面碰撞乘員損傷防護(hù)水平，都具有非常重要的現(xiàn)實(shí)意義和工程應(yīng)用價值。通過對側(cè)面碰撞人體損傷生物力學(xué)的研究背景、基本理論以及國內(nèi)外研究現(xiàn)狀進(jìn)行綜述，指出了當(dāng)前側(cè)面碰撞安全與人體損傷生物力學(xué)領(lǐng)域存在的不足，特別是國內(nèi)相關(guān)方面研究的不足，并由此提出論文的研究內(nèi)容和技術(shù)路線。首先，在深入理解人體解剖學(xué)結(jié)構(gòu)以及有限元理論的基礎(chǔ)上，基于中國50百分位男性志愿者的醫(yī)學(xué)影像數(shù)據(jù)，建立了新一代、更高精度的乘員生物力學(xué)模型；與之前模型相比，新版

4、乘員生物力學(xué)模型具有更加精細(xì)、更加真實(shí)的人體細(xì)節(jié)組織結(jié)構(gòu)，模型在軟組織建模、組織材料本構(gòu)、關(guān)節(jié)連接、顱骨-顱腦系統(tǒng)和心臟-主動脈系統(tǒng)的流固耦合接觸關(guān)系等方面進(jìn)行了很大的改進(jìn)和優(yōu)化。然后，根據(jù)ISO/TR 9790技術(shù)規(guī)程推薦的人體模型側(cè)面碰撞仿生可靠性驗(yàn)證實(shí)驗(yàn)和評價方法，對乘員生物力學(xué)模型進(jìn)行了多種碰撞條件下整體和局部的側(cè)面碰撞仿生可靠性驗(yàn)證與評價。結(jié)果表明：乘員生物力學(xué)模型具有良好的側(cè)面碰撞仿生可靠性，能夠用于任何側(cè)面碰撞條件下乘員各部位的生物力學(xué)響應(yīng)與損傷機(jī)理研究。利用已構(gòu)建并經(jīng)過驗(yàn)證的乘員生物力學(xué)模型開展不同角度側(cè)面碰撞下乘員各部位的生物力學(xué)損傷研究。首先，根據(jù)FMVSS 201U法規(guī)選

5、取某自主品牌SUV 側(cè)面A 柱和B 柱的兩個內(nèi)飾參考點(diǎn)，對比分析了側(cè)面斜置碰撞和側(cè)面垂直碰撞條件下乘員頭部的腦組織損傷。結(jié)果表明：側(cè)面斜置碰撞下乘員頭部腦組織損傷更嚴(yán)重；乘員頭部與內(nèi)飾件碰撞過程中，腦組織呈典型的碰撞對側(cè)傷分布模式，損傷部位主要集中在碰撞對側(cè)大腦、小腦、腦干的交界區(qū)域；A 柱參考點(diǎn)不同水平角度和俯仰角度下乘員顱腦損傷的對比分析表明，頭部腦組織損傷對于碰撞水平角度的變化更為敏感。針對側(cè)面碰撞事故中致死率最高的創(chuàng)傷性主動脈破裂（TRA ），深入剖析了人體主動脈的解剖學(xué)結(jié)構(gòu)以及TRA 的損傷機(jī)理。通過構(gòu)建各向同性線彈性和各向正交異性線彈性兩種主動脈材料本構(gòu)的乘員生物力學(xué)模型，開展胸部

6、側(cè)面垂直碰撞和側(cè)面斜置碰撞下主動脈損傷的對比研究。研究結(jié)果表明：主動脈采用不同的材料本構(gòu)模型對模型胸部側(cè)面碰撞的整體響應(yīng)和損傷沒有影響，但主動脈的應(yīng)變響應(yīng)存在差異，采用各向正交異性線彈性材料的主動脈對于碰撞載荷的響應(yīng)更為敏感；相同側(cè)面沖擊能量下，側(cè)面斜置碰撞造成的肋骨以及內(nèi)臟組織損傷程度也比側(cè)面垂直碰撞更嚴(yán)重，但側(cè)面垂直碰撞造成的胸部主動脈的損傷比側(cè)面斜置碰撞更嚴(yán)重；兩種側(cè)面碰撞條件下胸腔和主動脈的運(yùn)動變形不同是導(dǎo)致主動脈損傷存在差異的主要原因。針對側(cè)面碰撞事故中極易受到傷害的骨盆部位，構(gòu)建了四種不同類型的乘員骨盆生物力學(xué)模型（V-Hex 模型、C-Hex 模型、V-HS 模型和C-HS 模型

7、）。通過不同加載條件下骨盆模型響應(yīng)精度的對比分析發(fā)現(xiàn)：皮質(zhì)骨變厚度分布的全六面體單元骨盆模型（V-Hex 模型）具有最高的仿真準(zhǔn)確度，該模型真實(shí)模擬了骨盆的微觀結(jié)構(gòu)，能夠在降低皮質(zhì)骨厚度的同時，同步增大骨髓腔內(nèi)松質(zhì)骨的范圍，可以真實(shí)地反映人體老化過程中骨骼內(nèi)部皮質(zhì)骨和松質(zhì)骨的變化；但由于模型更精細(xì)，所需計算量比較大，不適于較大規(guī)模的模型計算。通過不同皮質(zhì)骨厚度和不同彈性模量下的損傷研究發(fā)現(xiàn)：皮質(zhì)骨厚度和彈性模量對于骨盆側(cè)面碰撞損傷具有重要影響；老年人由于骨質(zhì)鈣化，皮質(zhì)骨厚度變薄，彈性模量降低，在側(cè)面碰撞事故中更容易發(fā)生骨盆骨折。最后，在C-NCAP 側(cè)面碰撞實(shí)驗(yàn)規(guī)程的框架下，利用乘員生物力學(xué)模

8、型對某自主品牌SUV 的側(cè)面碰撞安全性進(jìn)行評價，并與樣車側(cè)面碰撞試驗(yàn)中ES-II 假人的評價結(jié)果進(jìn)行對比。結(jié)果表明：論文提出的基于乘員生物力學(xué)模型的汽車碰撞安全評價方法在理論和技術(shù)上切實(shí)可行；乘員生物力學(xué)模型的損傷評價結(jié)果比假人模型預(yù)測結(jié)果更加清楚、詳細(xì)，用于汽車安全結(jié)構(gòu)改進(jìn)更加有針對性，因此利用乘員生物力學(xué)模型進(jìn)行汽車碰撞安全設(shè)計和評價，相對傳統(tǒng)方法具有獨(dú)特的優(yōu)勢和先進(jìn)性。論文的研究工作對于促進(jìn)我國汽車安全設(shè)計與乘員損傷評價、完善汽車安全法規(guī)具有重要的借鑒意義和實(shí)用價值。關(guān)鍵字：汽車；側(cè)面碰撞；乘員損傷；生物力學(xué)響應(yīng)；損傷評價IIABSTRACTAutomobile products hav

9、e provided great convenience for human society. However, the loss of casualties and property caused by automobile collisions is also very huge. According to the latest statistics of the World Health Organization, there were more than 1.2 million people being killed and 20-50 million people geting hu

10、rt in road traffic accidents every year, which meaned an economic loss of more than 500 billion dollar. The side collisions is a kind of particularly frequent and dangerous form of vehicle accidents. Compared with the frontal collisions, side collisions can lead to more serious casualties owing to t

11、he weak strength of the side structure, the little energy absorption and the limited space between occupants and the vehicle door. As is well known to all, the ultimate purpose of vehicle safety design is to ensure human safety. And the performance of vehicle crash safety mainly depends on the injur

12、y severity of the occupant in the crash. Therefore, the in-depth study of the biomechanical responses, injury mechanism and injury tolerance in defferent parts of the human body in side impacts is of vital practical significance and engineering application value to the design of vehicle structure sa

13、fety, the improvement of vehicle safety assessment criterion and occupants protection.Limitations of the study on side impact and human injury biomechanics, in particular for the shortages of the related study in China, are summaried by reviewing the research background, the basic theory and the res

14、earch status at home and abroad, followedby the contents and technique route of this study. First of all, a new verion of occupant biomechanical model with higher precision is developed based on the CT and MR image data of a volunteer representing the physical characteristics of the 50th percentile

15、Chinese male. Compared with the old one, the current occupant biomechanical model has more detailed and more realistic human body tissues, which can be observed in the creation of soft tissues, the optimization of constitutive material model, the modeling of articular joints, and the simulation of t

16、he fluid-struture interaction in the aortic system and the skull-brain system. Afterwards, the biofidelity of the occupant biomechanical model is analyzed and evaluated based on the PMHS (Past Mortal Human Subject tests of defferent parts of human body inIIIvarious side impact conditions provided by

17、 ISO-TR9790 procedures. The results show that the occupant biomechanical model developed in this study can possess a high level of biofidelity in side impacts. And it can feel up to the study of the biomechanical responses and injury mechanism for defferent body parts in any side impact conditions.B

18、ased on the occupant biomechanical model developed in this study, thestudy of the biomechanical injury for defferent body parts in defferent derection of side impact is performed. First, the traumatic brain injury (TBI of the occupant in oblique and perpendicular side impacts is discussed by the imp

19、act simulations of the occupants head model with the reference points on the surface of the interior part in the A pillar and B pillar according to FMVSS 201U regulation. The results indicate that the occupants brain injury in oblique side impact is more serious than that in perpendicular side impac

20、t. During the impact, the brains inury type presents an obovious pattern of contralateral injury distribution comparing to the impact position. The brains inury manly distributes on the connected regions of the brain, the cerebellum and the brain stem opposite to the impact position of the forehead.

21、 In addition, the sensitivity study of occupants brain injury in defferent horizontal and defferent pitch angels impacting on the A pillar demonstrated that the brains inury is more sensitive to the change of the horizontal impact angel.In view of the high fatality resulting in the traumatic rupture

22、 of the aorta (TRA in side collisions, the anatomical structure and injury mechanism of TRA is investigated in-depth. Ultilizing the occupant biomechanical models with isotropic linear elastic material model and orthotropic linear elastic material model of the aortic tissue, the injuries of the thor

23、ax and aorta in perpendicular and oblique side impacts are analyzed. The results reveal that the change of the aortic constitutive material model has few infulunce on the thoracic responses and injury. However, the longitudinal Lagrange strain responses of the descending thoracic aorta are distinctl

24、y not equal. Comparatively speaking, the model with orthotropic linear elastic aortic material model presents more sensitive to the change of side impact. Under the same impact energy, the fractures of the thoracic ribcage and injuryies of the internal organs in oblique side impact are much more ser

25、ious than those in perpendicular side impact. Nevertheless, the aortic injury in perpendicular side impact is more serious than that in oblique side impact. The difference of injury severity in the aorta can be accounted for the IVdifference of their movements and deformations during perpendicular a

26、nd oblique side impacts.Given that the occupants pelvis is very vulnerable to side collisions, four different occupants pelvic model with different modeling in the element type and thickness of the pelvis coritical bone (the V-Hex model, the C-Hex model, the V-HS model and the C-HS model are created

27、. Through the comparisons of the four models predictions under different loading conditions, it is found that the all-hex model with variable cortical bone thickness (the V-Hex model shows the highest accurancy in simulations. The V-Hex model accurantely models the microstructures of the pelvic bone

28、. In the V-Hex model, the cortical bone thickness can be thinned with the marrow cavity (the cancellous bone being enlarged at the same time. This phenomenon agrees with the bone mineral content alterations in older people. However, the V-Hex model may not be favorable for some applicat ions, in whi

29、ch the models element number is too large. Compared with other types of pelvic model, the computing time of the V-Hex model is much longer owing to the small element size in it. From sensitivity studies of the the pelvis responses and injuries to variations in pelvis cortical bone thickness, bone ma

30、terial properties, and loading conditions, it is found that alterations of the thickness and Youngs modulus of the cortical bone has a more significant effect on pelvis injury. Along with aging, the bone mineral density and cortical bone Youngs modulus of the pelvis is gradually reducing. Meanwhile,

31、 the cortex thickness is thinning while the marrow cavity is enlarging. There fore, older people are more susceptible to severe injury in side impacts.Finally, the assessment of a SUVs safety performance in side impact is carried out ultalizing the occupant biomechanical model according to the side

32、impact regulations in C-NCAP (China-New Car Assessment Program. Moreover, the assessment results of the occupant biomechanical model are compared with those of the ES-II dummy in the side impact test of the sample car. The reaults indicate that the assessment metod of vehicle crash safety on the bas

33、is of the occupant biomechanical model in this tudy is feasible on the theory and technology. The assessment results of the occupant biomechanical model are much more detailed and clear than those of the mechanical dummy, and are more targetd to the improvement of automobile structure safety. Theref

34、ore, the design and assessment of vehicle crash safety based on the occupant biomechanical model have a unique advantage andVadvancement comparering to the traditional methods. In conclusion, the study in this paper will provide important significance and practical value to the improvement of vehicl

35、e safety design, occupants injury protection and automobile safety regulations.Keywords: Automobile; Side impact; Occupant injury; Biomechanical response; Injury assessmentVI目 錄摘 要 . . I ABSTRACT . III第一章 緒論 . . 11.1 論文研究背景與意義 . 11.2 側(cè)面碰撞生物力學(xué)損傷與安全法規(guī)標(biāo)準(zhǔn) . 31.2.1 側(cè)面碰撞與乘員損傷 . . 31.2.2 側(cè)面碰撞乘員損傷評價標(biāo)準(zhǔn) . . 6

36、1.2.3 側(cè)面碰撞安全法規(guī)介紹 . . 111.3 側(cè)面碰撞生物力學(xué)研究方法 . 141.3.1 事故損傷統(tǒng)計與分析 . . 141.3.2 生物樣本實(shí)驗(yàn) . . 151.3.3 機(jī)械模型實(shí)驗(yàn) . . 161.3.4 數(shù)字模型仿真 . . 171.4 國內(nèi)外研究進(jìn)展 . 201.4.1 側(cè)面碰撞PMHS 實(shí)驗(yàn) . . 201.4.2 側(cè)面碰撞生物力學(xué)模型 . . 241.5 目前存在的主要問題 . 271.6 論文主要研究內(nèi)容與課題來源 . 28第二章 基于中國人體特征的側(cè)面碰撞乘員生物力學(xué)模型 . 312.1 引言 . 312.2 有限元建?；纠碚?. 312.2.1 顯式積分算法 . . 312.2.2 常用單元類型 . . 322.2.3 常用材料類型 . . 342.3 模型建立方法與步驟 . 352.4 側(cè)面碰撞乘員生物力學(xué)模型 . 372.4.1 頭部生物力學(xué)模型 . . 382.4.2 軀干生物力學(xué)模型 . . 41VII2.4.3 其他部位生物力學(xué)模型 . . 462.4.5 模型中生物組織材料參數(shù) . . 462.5 本章小結(jié) . 50第三章 基于ISO/TR 9790的側(cè)面碰撞乘員生物力學(xué)模型仿生可靠性驗(yàn)證 . . 513.1 引言 . 513.2 基于ISO/TR 9790技術(shù)規(guī)程