基于人體有限元模型的汽車前碰撞中駕駛員下肢損傷生物力學(xué)研究
發(fā)布時(shí)間：2018-09-14 14:43
【摘要】：隨著安全帶配帶率的提升及安全氣囊在汽車中的普遍使用，乘員頭部及胸部在交通事故中受到嚴(yán)重?fù)p傷的比例持續(xù)降低。美國NASS/CDS的1993－2001年事故統(tǒng)計(jì)結(jié)果顯示，在前碰撞所有AIS2+損傷中，下肢占36%，損失的生命年（LLI）所占比率達(dá)到了46%，下肢損傷已超過頭、胸部成為事故中受到中等程度及以上（AIS2+）損傷風(fēng)險(xiǎn)最大的部位。下肢損傷一般不是交通事故中導(dǎo)致乘員死亡的直接因素，但其恢復(fù)期較長、且會(huì)導(dǎo)致巨大的傷痛、下肢生理機(jī)能喪失甚至殘疾，是汽車碰撞安全研究中不容忽視的問題。 為了更好地分析乘員下肢在前碰撞中的損傷機(jī)理及耐受限值，本文基于一名中等身材的成年男性下肢解剖學(xué)結(jié)構(gòu)，使用軟件Hyperworks11.0建立起一個(gè)能較好反映下肢生理學(xué)特征的坐姿下肢有限元模型，模型包含骨骼（骨盆、骶骨、股骨、髕骨、脛/腓骨、足部骨骼）及軟組織（肌肉、皮膚、關(guān)節(jié)囊、關(guān)節(jié)軟骨、韌帶、肌腱）。建立后的下肢模型含有97個(gè)部件，單元總數(shù)為65,626。其中實(shí)體單元為40,155，殼體單元25,263，彈簧單元208個(gè)。通過與9組經(jīng)典的尸體實(shí)驗(yàn)結(jié)果對比驗(yàn)證，表明下肢有限元模型建模方法正確、材料選用合理，，具有較好的生物逼真度，可用于后續(xù)的乘員下肢損傷機(jī)理及損傷預(yù)測研究中。 基于建立的乘員下肢模型，文中開展了一系列前碰撞載荷條件下的車內(nèi)乘員下肢損傷生物力學(xué)研究，包括：股骨在受到膝部軸向壓力-外部彎矩時(shí)的損傷機(jī)理、耐受限值研究；乘員下肢受膝墊碰撞力作用時(shí)不同髖關(guān)節(jié)姿態(tài)對骨盆損傷的影響分析；足/踝部在乘員艙侵入條件下的損傷機(jī)理及防護(hù)參數(shù)研究。最后，結(jié)合整車有限元模型進(jìn)行了不同重疊率前碰撞下的下肢損傷對比分析。 在建立下肢模型基礎(chǔ)上，本文就股骨生理特性對其耐受限值的影響進(jìn)行分析。在之后開展的外部彎矩對股骨耐受限值影響研究中，本文使用曲梁力學(xué)模型及有限元虛擬實(shí)驗(yàn)分析了股骨分別受到膝部軸向壓力-股骨髁彎矩及膝部軸向力-股骨干橫向沖擊彎矩兩種形式載荷時(shí)的損傷機(jī)理及耐受限值。結(jié)果表明：外部彎矩載荷不僅會(huì)影響到股骨的失效部位，而且會(huì)影響到股骨的耐受限值。在6組受軸向力-股骨髁彎矩載荷的虛擬試驗(yàn)中，預(yù)加軸向力為8.0kN及以上時(shí)，失效部位發(fā)生股骨頸部，其失效截面彎矩為285Nm~295Nm，而預(yù)加軸向力為0-6kN時(shí)，失效位置在距股骨末端134.9~171mm的股骨干區(qū)域，其失效截面彎矩為381Nm~443Nm；在受軸向力-股骨干橫向沖擊載荷的虛擬試驗(yàn)中，載荷為8.0kN-0.64kN及8.9kN-0kN時(shí)，失效同樣發(fā)生股骨頸部，其失效截面彎矩為307.2Nm和296Nm；而預(yù)加軸向力為0-6kN時(shí)，股骨中截面骨折，失效彎矩為382Nm~400.7Nm。研究結(jié)果解釋了膝部軸向沖擊實(shí)驗(yàn)中股骨失效全發(fā)生在頸部，而前碰撞事故中卻有大量股骨干骨折發(fā)生時(shí)軸向力比損傷準(zhǔn)則(10kN)中小的現(xiàn)象。 基于下肢模型，本文進(jìn)行了不同的髖關(guān)節(jié)屈曲角及展角下的膝部軸向力沖擊虛擬試驗(yàn)研究。結(jié)果表明：由于髖臼壁各受力點(diǎn)強(qiáng)度不同，膝部軸向沖擊下的髖關(guān)節(jié)姿態(tài)會(huì)直接影響到骨盆骨折部位及失效值。隨著髖關(guān)節(jié)屈曲角及展角的增大，損傷部位由髂骨轉(zhuǎn)移到髖臼。骨盆失效值隨屈曲角的增加而增大13.5%~34.4%，但其失效值隨展角的增加先增大后減小，且變化范圍為6.0%~20.9%。 足/踝部是前碰撞中下肢最容易受到損傷的部位，結(jié)合下肢有限元模型，先建立并驗(yàn)證了奇瑞某車型的駕駛員-約束系統(tǒng)有限元模型。然后對前碰撞中引起足/踝部損傷的儀表臺設(shè)計(jì)角度、踏板的向后和向上侵入量、踏板內(nèi)/外翻角度及踏板的背屈翻轉(zhuǎn)角度五組參數(shù)進(jìn)行了16組正交實(shí)驗(yàn)分析。結(jié)果表明：其中11組實(shí)驗(yàn)產(chǎn)生了小腿或足/髁部的損傷；對脛骨軸向力最敏感的參數(shù)是踏板向上侵入量；脛骨合成彎矩和脛骨指數(shù)最敏感的參數(shù)是踏板向后侵入量；踏板背屈轉(zhuǎn)角及踏板后移量的增大會(huì)引起到踝關(guān)節(jié)最大背屈角的增加；在一定范圍內(nèi)，膝墊夾角越大，越有助于減小因背屈引起的踝關(guān)節(jié)損傷。對實(shí)驗(yàn)結(jié)果進(jìn)行深入分析還發(fā)現(xiàn)：脛骨指數(shù)與踝關(guān)節(jié)的損傷沒有必然聯(lián)系，而背屈及內(nèi)/外翻轉(zhuǎn)角超過了踝關(guān)節(jié)的生理活動(dòng)范圍是引起踝關(guān)節(jié)損傷的直接原因。 為研究不同重疊率前碰撞中駕駛員下肢的損傷特點(diǎn)，首先對奇瑞公司某有限元整車模型進(jìn)行了驗(yàn)證；然后使用其進(jìn)行全寬正面碰撞、40%及25%偏置碰撞的模擬，并總結(jié)了三種重疊率前碰撞形式下的整車耐撞性特點(diǎn)；最后分別提取三種碰撞形式下的乘員艙侵入情況及整車加速度作為初始邊界條件，結(jié)合已建立的駕駛員-約束系統(tǒng)模型開展了三種前碰撞形式的下肢損傷研究。結(jié)果顯示：由于重疊率不同，整車加速度、乘員艙侵入部位及大小都有較大差別，重疊率越小，則侵入量越大，平均加速度則越�。徊煌呐鲎蔡卣髟斐闪瞬煌南轮珦p傷特點(diǎn)：在25%偏置碰撞中，巨大的膝墊及踏板侵入引起了左側(cè)股骨頸骨折和雙側(cè)踝關(guān)節(jié)損傷；在100%正面碰撞中也產(chǎn)生了右側(cè)踝關(guān)節(jié)損傷，而40%偏置碰撞中無下肢損傷。進(jìn)一步分析表明：下肢的損傷風(fēng)險(xiǎn)與整車碰撞加速度波形直接相關(guān)；乘員艙侵入量與足/踝損傷并不是線性關(guān)系；同等侵入量下，加速踏板比歇腳踏板更容易造成踝關(guān)節(jié)背屈的后距脛韌帶失效及距骨骨折損傷。 綜上所述，文中建立的下肢有限元模型可作為乘員下肢損傷生物力學(xué)研究的有效工具。而使用該模型進(jìn)行的股骨、骨盆、足/踝部損傷機(jī)理、耐受限值及損傷防護(hù)的研究結(jié)果為前碰撞載荷下的駕駛員下肢損傷防護(hù)設(shè)計(jì)提供了有益的參考。
[Abstract]:With the increase of seat belt allocation rate and the widespread use of airbags in automobiles, the proportion of serious head and chest injuries in traffic accidents continues to decrease. According to the accident statistics of NASS/CDS from 1993 to 2001, 36% of all AIS2 + injuries were caused by pre-collision, and 36% of all AIS2 + injuries were caused by lower limbs, and the proportion of lost life years (LLI) reached a high level. Lower limb injury is not a direct cause of death in traffic accidents, but it has a long recovery period, and can cause great pain, loss of lower limb physiological function and even disability. It is a vehicle crash safety research. We should not neglect the problems.
In order to better analyze the injury mechanism and tolerance limit of the occupant's lower limbs during anterior collision, a finite element model of sitting lower limbs was established based on the anatomical structure of the lower limbs of a middle-sized adult male. The model was composed of skeleton (pelvis, sacrum, femur, patella) and HyperWorks 11.0. Bone, tibia/fibula, foot bones, and soft tissues (muscle, skin, capsule, articular cartilage, ligament, tendon). The established lower limb model contains 97 parts, with a total number of units of 65,626. Among them, solid units are 40,155, shell units 25,263, and spring units 208. The modeling method is correct, the material selection is reasonable, and the model has good biological fidelity, which can be used in the follow-up study of lower limb injury mechanism and injury prediction.
Based on the passenger lower limb model, a series of biomechanical studies on the lower limb injuries of in-car passengers under the condition of anterior collision load were carried out, including: the injury mechanism of femur under axial pressure and external bending moment of knee, the tolerance limit; the pelvic injuries caused by different hip joint postures when the lower limb was subjected to knee pad impact force The impact analysis; the foot/ankle injury mechanism and protective parameters under the condition of occupant cabin invasion. Finally, combined with the vehicle finite element model, the comparative analysis of lower limb injury under different overlap rate of anterior collision was carried out.
Based on the establishment of the lower limb model, the effect of femoral physiological characteristics on the femoral tolerance limit was analyzed. In the subsequent study of the influence of external bending moments on the femoral tolerance limit, curved beam mechanics model and finite element virtual experiment were used to analyze the femur subjected to knee axial pressure-femoral condyle bending moment and knee axial force-femoral condyle axial force respectively. Damage mechanism and tolerance limits of femoral shaft under transverse impact bending moments were studied. The results showed that external bending moments not only affected the failure site of femur, but also the tolerance limit of femur. The failure cross-section moment of femoral neck was 285 Nm~295 Nm, and the failure position was 134.9~171 mm from the end of femur when the axial force was 0-6 kN. The failure cross-section moment of femoral neck was 381 Nm~443 Nm when the axial force was 0-0.64 kN and 8.9 kN-0 kN in the virtual test under the axial force-transverse impact load. The failure cross-section moment of the femoral neck was 307.2 Nm and 296 Nm, while the failure cross-section moment was 382 Nm ~ 400.7 Nm when the axial force was 0-6 kN. The results explained that the failure of the femur occurred in the neck during the knee axial impact test, but the axial force ratio of the femoral shaft fracture in the anterior impact accident was more accurate than that of the injury. (10kN) medium and small phenomena.
Based on the lower limb model, the virtual impact tests of knee axial force under different hip flexion angles and abduction angles were carried out. The results show that the hip joint posture under axial impact of knee has a direct impact on the position and failure value of pelvic fracture due to the strength of each force point on the acetabular wall. The pelvic failure value increased by 13.5%~34.4% with the increase of flexion angle, but it increased first and then decreased with the increase of flexion angle, and the range of change was 6.0%~20.9%.
The foot/ankle is the most vulnerable part of the lower limb in the fore-impact. Combining with the finite element model of the lower limb, the driver-restraint system finite element model of a Chery model is established and validated. Sixteen orthogonal experiments were carried out to analyze the five parameters of the plate's back-bending angle.The results showed that 11 groups of experiments produced leg or foot/condyle injuries.The most sensitive parameter to the tibial axial force was the upward invasion of the pedal.The most sensitive parameters to tibial synthetic bending moment and tibial index were the backward invasion of the pedal. Increasing the angle and pedal displacement will increase the maximum ankle dorsiflexion angle; in a certain range, the greater the knee pad angle, the more conducive to reducing the ankle injury caused by back flexion. The physiological range of ankle joint is the direct cause of ankle injury.
In order to study the characteristics of driver's lower limb injury in different overlap rate pre-collision, a finite element vehicle model of Chery Company was validated firstly, then the full-width frontal impact, 40% and 25% offset impact were simulated, and the crashworthiness characteristics of the vehicle under three overlap rate pre-collision forms were summarized. The results show that, due to the different overlap rate, the acceleration of the whole vehicle, the location and size of the occupant compartment are different, and the overlap rate is smaller. The greater the amount of invasion, the smaller the average acceleration; different collision characteristics caused different characteristics of lower limb injury: in 25% offset collision, the huge knee pad and pedal invasion caused left femoral neck fracture and bilateral ankle injury; in 100% frontal collision, the right ankle injury was also produced, while in 40% offset collision there was no lower limb injury. Limb injury. Further analysis showed that the risk of lower limb injury was directly related to the acceleration waveform of vehicle crash; occupant cabin invasion was not linear with foot/ankle injury; acceleration pedal was more likely to cause posterior tibial ligament failure and talus fracture injury than rest pedal under the same amount of invasion.
In conclusion, the finite element model of the lower limb established in this paper can be used as an effective tool for the biomechanical study of lower limb injuries in passengers.
【學(xué)位授予單位】：湖南大學(xué)
【學(xué)位級別】：博士
【學(xué)位授予年份】：2014
【分類號】：U467.14;R641
本文編號：2243009
[Abstract]:With the increase of seat belt allocation rate and the widespread use of airbags in automobiles, the proportion of serious head and chest injuries in traffic accidents continues to decrease. According to the accident statistics of NASS/CDS from 1993 to 2001, 36% of all AIS2 + injuries were caused by pre-collision, and 36% of all AIS2 + injuries were caused by lower limbs, and the proportion of lost life years (LLI) reached a high level. Lower limb injury is not a direct cause of death in traffic accidents, but it has a long recovery period, and can cause great pain, loss of lower limb physiological function and even disability. It is a vehicle crash safety research. We should not neglect the problems.
In order to better analyze the injury mechanism and tolerance limit of the occupant's lower limbs during anterior collision, a finite element model of sitting lower limbs was established based on the anatomical structure of the lower limbs of a middle-sized adult male. The model was composed of skeleton (pelvis, sacrum, femur, patella) and HyperWorks 11.0. Bone, tibia/fibula, foot bones, and soft tissues (muscle, skin, capsule, articular cartilage, ligament, tendon). The established lower limb model contains 97 parts, with a total number of units of 65,626. Among them, solid units are 40,155, shell units 25,263, and spring units 208. The modeling method is correct, the material selection is reasonable, and the model has good biological fidelity, which can be used in the follow-up study of lower limb injury mechanism and injury prediction.
Based on the passenger lower limb model, a series of biomechanical studies on the lower limb injuries of in-car passengers under the condition of anterior collision load were carried out, including: the injury mechanism of femur under axial pressure and external bending moment of knee, the tolerance limit; the pelvic injuries caused by different hip joint postures when the lower limb was subjected to knee pad impact force The impact analysis; the foot/ankle injury mechanism and protective parameters under the condition of occupant cabin invasion. Finally, combined with the vehicle finite element model, the comparative analysis of lower limb injury under different overlap rate of anterior collision was carried out.
Based on the establishment of the lower limb model, the effect of femoral physiological characteristics on the femoral tolerance limit was analyzed. In the subsequent study of the influence of external bending moments on the femoral tolerance limit, curved beam mechanics model and finite element virtual experiment were used to analyze the femur subjected to knee axial pressure-femoral condyle bending moment and knee axial force-femoral condyle axial force respectively. Damage mechanism and tolerance limits of femoral shaft under transverse impact bending moments were studied. The results showed that external bending moments not only affected the failure site of femur, but also the tolerance limit of femur. The failure cross-section moment of femoral neck was 285 Nm~295 Nm, and the failure position was 134.9~171 mm from the end of femur when the axial force was 0-6 kN. The failure cross-section moment of femoral neck was 381 Nm~443 Nm when the axial force was 0-0.64 kN and 8.9 kN-0 kN in the virtual test under the axial force-transverse impact load. The failure cross-section moment of the femoral neck was 307.2 Nm and 296 Nm, while the failure cross-section moment was 382 Nm ~ 400.7 Nm when the axial force was 0-6 kN. The results explained that the failure of the femur occurred in the neck during the knee axial impact test, but the axial force ratio of the femoral shaft fracture in the anterior impact accident was more accurate than that of the injury. (10kN) medium and small phenomena.
Based on the lower limb model, the virtual impact tests of knee axial force under different hip flexion angles and abduction angles were carried out. The results show that the hip joint posture under axial impact of knee has a direct impact on the position and failure value of pelvic fracture due to the strength of each force point on the acetabular wall. The pelvic failure value increased by 13.5%~34.4% with the increase of flexion angle, but it increased first and then decreased with the increase of flexion angle, and the range of change was 6.0%~20.9%.
The foot/ankle is the most vulnerable part of the lower limb in the fore-impact. Combining with the finite element model of the lower limb, the driver-restraint system finite element model of a Chery model is established and validated. Sixteen orthogonal experiments were carried out to analyze the five parameters of the plate's back-bending angle.The results showed that 11 groups of experiments produced leg or foot/condyle injuries.The most sensitive parameter to the tibial axial force was the upward invasion of the pedal.The most sensitive parameters to tibial synthetic bending moment and tibial index were the backward invasion of the pedal. Increasing the angle and pedal displacement will increase the maximum ankle dorsiflexion angle; in a certain range, the greater the knee pad angle, the more conducive to reducing the ankle injury caused by back flexion. The physiological range of ankle joint is the direct cause of ankle injury.
In order to study the characteristics of driver's lower limb injury in different overlap rate pre-collision, a finite element vehicle model of Chery Company was validated firstly, then the full-width frontal impact, 40% and 25% offset impact were simulated, and the crashworthiness characteristics of the vehicle under three overlap rate pre-collision forms were summarized. The results show that, due to the different overlap rate, the acceleration of the whole vehicle, the location and size of the occupant compartment are different, and the overlap rate is smaller. The greater the amount of invasion, the smaller the average acceleration; different collision characteristics caused different characteristics of lower limb injury: in 25% offset collision, the huge knee pad and pedal invasion caused left femoral neck fracture and bilateral ankle injury; in 100% frontal collision, the right ankle injury was also produced, while in 40% offset collision there was no lower limb injury. Limb injury. Further analysis showed that the risk of lower limb injury was directly related to the acceleration waveform of vehicle crash; occupant cabin invasion was not linear with foot/ankle injury; acceleration pedal was more likely to cause posterior tibial ligament failure and talus fracture injury than rest pedal under the same amount of invasion.
In conclusion, the finite element model of the lower limb established in this paper can be used as an effective tool for the biomechanical study of lower limb injuries in passengers.
【學(xué)位授予單位】：湖南大學(xué)
【學(xué)位級別】：博士
【學(xué)位授予年份】：2014
【分類號】：U467.14;R641
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