BACKGROUND:Mechanical experiment of finite element numerical simulation is the effective method to research the biomechanical structure of human body. OBJECTIVE:To establish the three-dimensional finite element model of a normal 6-year-old child’s humerus. METHODS:CT images of a 6-year-old child volunteer were imported to the Mimics 10.01 software. The threshold segmentation method was used to rebuild the humerus three-dimensional model. The surface optimization treatment and surface patches dicision were performed on the surface of the model with Geomagic Studio 12.0 software. Then the mesh generation was completed in the software TrueGrid. Final y, the material properties were set and the finite element model was completed. The boundary conditions and constrains were exerted to simulate the three-point-bending test of humeurs. After the simulation, the results were outputted. RESULTS AND CONCLUSION:The humerus finite element model included 3 024 nodes and 18 758 nodes-hexahedron elements. The 0.01 m/s and 3 m/s dynamic loads were loaded respectively, then the central humerus fracture occurred and the load-displacement curve was close to the cadaver test results. The simulation results show that the simulation results of children humerus finite element model are close to the cadaver’s test, and the finite element simulation method can simulate the physical properties of the human skeleton very wel .

Objective To explore the influence of child head injury under different impact angles by applying the finite element model of six-year-old child pedestrian as specified in the European New Car Assessment Programme (Euro NCAP). Methods Based on the finite element model of 6-year-old pedestrian with detailed anatomical structure as specified by the Euro NCAP (TB024), four groups of simulation experiments were set up to explore the mechanism of head injury in children under different impact angles. The initial position for head mass center was on the longitudinal center line of the car. The initial speed of the car was 40 km/h. The car contacted with the model from the direction of the right (0°), the front (90°), the left (180°) and the back (270°). The kinematics differences and head impact responses were compared, and injuries of the facial bone and skull were analyzed. Results Through the analysis of head contact force, acceleration of head mass center, resultant velocity of head mass center with the vehicle, head injury criterion (HIC15), facial bone fracture and skull stress distribution, it was found that the risk of head fracture and brain contusion under back impact and front impact was higher than that under side impact. The risk of head fracture and brain contusion was highest under back impact, while the lowest under side impact. Conclusions Child pedestrian head injury was the largest under back impact. The results have important application values for the assessment and development of car-pedestrian collision protection device.

Based on the biomechanical response of human knee joint to a front impact in occupants accidents, a finite element (FE) model of human knee joint was developed by using computer simulation technique for impacting. The model consists of human anatomical structure, including femoral condyle, tibia condyle, fibular small head, patellar, cartilage, meniscus and primary ligament. By comparing the results of the FE model with experiments of the knee joint in axial load conditions, the validation of the model was verified. Furthermore, this study provides data for the mechanical of human knee joint injury, and is helpful for the design and optimization of the vehicle protective devices.
Biomechanical Phenomena ; Finite Element Analysis ; Humans ; Knee Injuries ; physiopathology ; Knee Joint ; anatomy & histology ; physiology ; Models, Anatomic ; Models, Biological

A validated 5th and 95th percentile Chinese head model was used to investigate the influence of head dimensions on the biomechanical responses by comparing acceleration, intracranial pressure and shear stress of the heads with different dimensions under the same impact energy. Moreover, the reasonability of scaling method used in the research considering head dimensions was discussed by respectively scaling the small head to a big one and scaling the big head to a small one. It therefore more scientifically provides a newer and more scientific reference for the assessment of head injury.
Anthropometry ; Asian Continental Ancestry Group ; Biomechanical Phenomena ; Brain Injuries ; physiopathology ; Craniocerebral Trauma ; physiopathology ; Finite Element Analysis ; Head ; anatomy & histology ; Humans ; Models, Anatomic

Head injury criterion (HIC) is a widely accepted injury criterion in assessing the injury potential of the human head under external loads. It has been used in vehicle safety regulations worldwide and helmet design. However, controversy about its applicability exists. In this study, two human head models of different size and mass were created to explore the applicability of HIC. Under three different impact loadings, the principal stresses of the two brains of the two different head models were calculated and compared with the corresponding HIC values. The influences on the application of HIC in head injury assessment were investigated. This study provides some new insights and leads new conclusions towards human head injury assessment.
Accidents, Traffic ; Craniocerebral Trauma ; diagnosis ; Finite Element Analysis ; Humans ; Injury Severity Score ; Models, Biological ; Reference Standards

The pelvis is one of the most likely affected areas of the human body in case of side impact, especially while people suffer from motor vehicle crashes. With the investigation of pelvis injury on side impact, the injury biomechanical behavior of pelvis can be found, and the data can help design the vehicle security devices to keep the safety of the occupants. In this study, a finite element (FE) model of an isolated human pelvis was used to study the pelvic dynamic response under different side impact conditions. Fracture threshold was established by applying lateral loads of 1000, 2000, 3000, 4000 and 5000 N, respectively, to the articular surface of the right acetabulum. It was observed that the smaller the lateral loads were, the smaller the von Mises stress and the displacement in the direction of impact were. It was also found that the failure threshold load was near 3000 N, based on the fact that the peak stress would not exceed the average compressive strength of the cortical bone. It could well be concluded that with better design of car-door and hip-pad so that the side impact force was brought down to 3000 N or lower, the pelvis would not be injured.
Accidents, Traffic ; Biomechanical Phenomena ; Computer Simulation ; Finite Element Analysis ; Fractures, Bone ; physiopathology ; prevention & control ; Humans ; Pelvis ; injuries ; Stress, Mechanical

AIM: To compare the protective effects of tongxinluo, a Chinese medicine, and carvedilol and valsartan on myocardium microvascular endothelial function and integrity after late reperfusion of acute myocardial infarction (AMI) in rabbits. METHODS: Forty-eight rabbits were randomly assigned to the following groups: (1) sham operated rabbits; (2) ischemia-reperfusion (I-R) controls; (3) tongxinluo (1.0 g?kg~ -1?d~ -1); (4) carvedilol (5 mg?kg~ -1?d~ -1); (5) valsartan (10 mg?kg~ -1?d~ -1) and (6) ticlopidine + aspirine (30 and 20 mg?kg~ -1?d~ -1, respectively) groups. After 3 d of drug treatment, the left coronary artery in the rabbit was ligated for 2 h and loosed subsequently for another 2 h. The serum levels of nitric oxide (NO_2~-/NO_3~-) and endothelin (ET) at baseline before AMI, 2 h after both AMI and reperfusion were examined. Also, the number of circulating endothelial cells (CEC), MI size and percentage myocardium focal bleeding incidence were determined 2 h after reperfusion. RESULTS: (1) The baseline level of NO_2~-/NO_3~- was significantly higher in tongxinluo group than that in other groups (all P

Two kinds of algorithm have been set forth to estimate the symmetry characteristic of live human skull on CT image. These CT images were treated with a series of processes such as coding into programs, formatting originals, binary coding, rectifying image deviation, detecting boundary edge, and quantitatively measuring the skull symmetry. The statistical analyses of measuring 3000 live human skull images have worked out the ratio and the distribution of the skull symmetry, so that dependable data are provided for establishing the human head injury biomechanics model. The results are of great practical value in the fields of anatomy, clinical medicine, biomechanies study, head injury analysis, etc.
Biomechanical Phenomena ; Cephalometry ; methods ; Female ; Humans ; Image Processing, Computer-Assisted ; methods ; Male ; Reference Values ; Skull ; anatomy & histology ; diagnostic imaging ; Tomography, X-Ray Computed

This study sought to measure accurately the thickness of the frontal, parietal and occipital bones of the alive human skull based on CT images. The images were treated with a series of processes by coding into a program: image segmentation and binary coding; eliminating edge interference; rectifying image deviation and clarifying boundary edge; redrawing the boundary and reference point fixing; and finally thickness measurement. The new method can measure not only the different points in one CT image but also the same point in massive CT images. The measurement results are of great practical value in the fields of anatomy, clinical medicine, biomechanics study, head injury analysis, etc.
Cephalometry ; methods ; Humans ; Radiographic Image Enhancement ; methods ; Skull ; anatomy & histology ; diagnostic imaging ; Tomography, X-Ray Computed

Objective To investigate the injury mechanisms of three-year-old child occupants by reconstructing a real traffic accident.Methods A traffic accident case from the CIREN database was reconstructed using a vehicle finite element model and a three-year-old child occupant injury bionic model(TUST IBMs 3YO-O).The Δv,mass of the vehicle,and deformation energy were comprehensively analyzed to calculate the collision velocity of the vehicle.This accident was simulated to present injuries to a child occupant,and the injury mechanisms were analyzed in depth.Results The TUST IBMs 3YO-O fully reconstructed the injuries of the child occupant in this case.The kinematic and biomechanical responses of the children's heads differed.The biomechanical response of the internal tissues and organs in the chest cavity showed no injury,however,the result ant chest acceleration at 3 ms reached 54 g,which exceeded the threshold.Conclusions In the future,it will be necessary to adopt biomechanical parameters for occupant safety evaluations.The application of human biomechanical models with high biofidelity to reconstruct occupant injuries in traffic accidents can not only be used to observe the kinematic responses of the occupant in the accident and analyze the injury mechanisms in depth,but also to provide references for virtual testing,as well as for the research and development of child occupant protection devices and the formulation of safety regulations.