Purpose:The toughest challenge in pedestrian traffic accident identification lies in ascertaining injurymanners.This study aimed to systematically simulate and parameterize 3 types of craniocerebral injuryincluding im...Purpose:The toughest challenge in pedestrian traffic accident identification lies in ascertaining injurymanners.This study aimed to systematically simulate and parameterize 3 types of craniocerebral injuryincluding impact injury,fall injury,and run-over injury,to compare the injury response outcomes ofdifferent injury manners.Methods:Based on the total human model for safety(THUMS)and its enhanced human model THUMShollow structures,a total of 84 simulations with 3 injury manners,different loading directions,andloading velocities were conducted.Von Mises stress,intracranial pressure,maximum principal strain,cumulative strain damage measure,shear stress,and cranial strain were employed to analyze the injuryresponse of all areas of the brain.To examine the association between injury conditions and injuryconsequences,correlation analysis,principal component analysis,linear regression,and stepwise linearregression were utilized.Results:There is a significant correlation observed between each criterion of skull and brain injury(p<0.01 in all Pearson correlation analysis results).A 2-phase increase of cranio-cerebral stress andstrain as impact speed increases.In high-speed impact(>40 km/h),the Von Mises stress on the skull waswith a high possibility exceed the threshold for skull fracture(100 MPa).When falling and makingtemporal and occipital contact with the ground,the opposite side of the impacted area experienceshigher frequency stress concentration than contact at other conditions.Run-over injuries tend to have amore comprehensive craniocerebral injury,with greater overall deformation due to more adequate kinetic energy conduction.The mean value of maximum principal strain of brain and Von Mises stress ofcranium at run-over condition are 1.39 and 403.8 MPa,while they were 1.31,94.11 MPa and 0.64,120.5 MPa for the impact and fall conditions,respectively.The impact velocity also plays a significant rolein craniocerebral injury in impact and fall loading conditions(the p of all F-test<0.05).A regressionequation of the 展开更多
Forensic biomechanics gradually has become a significant component of forensic science.Forensic biomechanics is evidence-based science that applies biomechanical principles and methods to forensic practice,which has c...Forensic biomechanics gradually has become a significant component of forensic science.Forensic biomechanics is evidence-based science that applies biomechanical principles and methods to forensic practice,which has constituted one of the most potential research areas.in this review,we introduce how finite element techniques can be used to simulate forensic cases,how injury criteria and injury scales can be used to describe injury severity,and how tests of postmortem human subjects and dummy can be used to provide essential validation data.This review also describes research progress and new applications of forensic biomechanics in China.展开更多
The study of the adhesion of millions of setae on the toes of geckos has been advanced in recent years with the emergence of new technology and measurement methods. The theory of the mechanism of adhesion by van der W...The study of the adhesion of millions of setae on the toes of geckos has been advanced in recent years with the emergence of new technology and measurement methods. The theory of the mechanism of adhesion by van der Waals forces is now accepted and broadly understood. However, this paper presents limitations of this theory and gives a new hypothesis of the biomechanism of gecko adhesion. The findings are obtained through measurements of the magnitude of the adhesion of setae under three different conditions, to show the close relationship between adhesion and status of the setae. They are reinforced by demonstrating two setal structures, follicle cells and hair, the former making the setae capable of producing bioelectrical charges, which play an important role in attachment and detachment processes. It is shown that the abundant muscular tissues at the base of the setae cells, which are controlled by peripheral nerves, are instrumental in producing the foot movement involved in attachment and detachment. Our study will further uncover the adhesion mechanism of geckos, and provide new ideas for designing and fabricating synthetic setae.展开更多
基金The study was funded by grants from the National Key Researchand Development Plan(2022YFC3302002)the National NaturalScience Foundation of China(82171872)+5 种基金Shanghai Yangfan SpecialProgramme(23YF1448700)Natural Science Foundation ofShanghai(21ZR1464600)the 2023 Open Foundation of Key Laboratory of Forensic Pathology,Ministry of Public Security,P.R.China(GAFYBL202308)Shanghai Key Laboratory of Forensic Medicine(21DZ2270800)Shanghai Forensic Service Platform(19DZ2290900)Central Research Institute Public Project(GY2023Z-3).
文摘Purpose:The toughest challenge in pedestrian traffic accident identification lies in ascertaining injurymanners.This study aimed to systematically simulate and parameterize 3 types of craniocerebral injuryincluding impact injury,fall injury,and run-over injury,to compare the injury response outcomes ofdifferent injury manners.Methods:Based on the total human model for safety(THUMS)and its enhanced human model THUMShollow structures,a total of 84 simulations with 3 injury manners,different loading directions,andloading velocities were conducted.Von Mises stress,intracranial pressure,maximum principal strain,cumulative strain damage measure,shear stress,and cranial strain were employed to analyze the injuryresponse of all areas of the brain.To examine the association between injury conditions and injuryconsequences,correlation analysis,principal component analysis,linear regression,and stepwise linearregression were utilized.Results:There is a significant correlation observed between each criterion of skull and brain injury(p<0.01 in all Pearson correlation analysis results).A 2-phase increase of cranio-cerebral stress andstrain as impact speed increases.In high-speed impact(>40 km/h),the Von Mises stress on the skull waswith a high possibility exceed the threshold for skull fracture(100 MPa).When falling and makingtemporal and occipital contact with the ground,the opposite side of the impacted area experienceshigher frequency stress concentration than contact at other conditions.Run-over injuries tend to have amore comprehensive craniocerebral injury,with greater overall deformation due to more adequate kinetic energy conduction.The mean value of maximum principal strain of brain and Von Mises stress ofcranium at run-over condition are 1.39 and 403.8 MPa,while they were 1.31,94.11 MPa and 0.64,120.5 MPa for the impact and fall conditions,respectively.The impact velocity also plays a significant rolein craniocerebral injury in impact and fall loading conditions(the p of all F-test<0.05).A regressionequation of the
基金The study was financially supported by grants from the National Key Research and Development Plan[grant number 2016YFC0800702]Council of National Science Foundation of China[grant numbers 81701863,81722027]+3 种基金Shanghai Key Laboratory of Forensic Medicine[grant number 17DZ2273200]Shanghai Forensic Service Platform[grant number 19DZ2290900]Central Research Institute Public Project[grant numbers GY2020G4,GY2019Z2]Opening Project of Shanghai Key Laboratory of Crime Scene Evidence[grant number 2019XCWZK03].
文摘Forensic biomechanics gradually has become a significant component of forensic science.Forensic biomechanics is evidence-based science that applies biomechanical principles and methods to forensic practice,which has constituted one of the most potential research areas.in this review,we introduce how finite element techniques can be used to simulate forensic cases,how injury criteria and injury scales can be used to describe injury severity,and how tests of postmortem human subjects and dummy can be used to provide essential validation data.This review also describes research progress and new applications of forensic biomechanics in China.
基金supported by the National Basic Research Program of China (Grant No. 2011CB302106)the National Natural Science Foundation of China (Grant Nos. 30770285, 51175249, 61175105 and 51105201)the Jiangsu Natural Science Foundation (Grant No. BK2009376)
文摘The study of the adhesion of millions of setae on the toes of geckos has been advanced in recent years with the emergence of new technology and measurement methods. The theory of the mechanism of adhesion by van der Waals forces is now accepted and broadly understood. However, this paper presents limitations of this theory and gives a new hypothesis of the biomechanism of gecko adhesion. The findings are obtained through measurements of the magnitude of the adhesion of setae under three different conditions, to show the close relationship between adhesion and status of the setae. They are reinforced by demonstrating two setal structures, follicle cells and hair, the former making the setae capable of producing bioelectrical charges, which play an important role in attachment and detachment processes. It is shown that the abundant muscular tissues at the base of the setae cells, which are controlled by peripheral nerves, are instrumental in producing the foot movement involved in attachment and detachment. Our study will further uncover the adhesion mechanism of geckos, and provide new ideas for designing and fabricating synthetic setae.
