{"title":"Strain-Rate Dependency of Axonal Tolerance for Uniaxial Stretching.","authors":"Hiromichi Nakadate, Evrim Kurtoglu, Hidenori Furukawa, Shoko Oikawa, Shigeru Aomura, Akira Kakuta, Yasuhiro Matsui","doi":"10.4271/2017-22-0003","DOIUrl":"https://doi.org/10.4271/2017-22-0003","url":null,"abstract":"<p><p>This study aims to clarify the relation between axonal deformation and the onset of axonal injury. Firstly, to examine the influence of strain rate on the threshold for axonal injury, cultured neurons were subjected to 12 types of stretching (strains were 0.10, 0.15, and 0.20 and strain rates were 10, 30, 50, and 70 s<sup>-1</sup>). The formation of axonal swellings and bulbs increased significantly at strain rates of 50 and 30 s<sup>-1</sup> with strains of 0.15 and 0.20, respectively, even though those formations did not depend on strain rates in cultures exposed to a strain of 0.10. Then, to examine the influence of the strain along an axon on axonal injury, swellings were measured at every axonal angle in the stretching direction. The axons that were parallel to stretching direction were injured the most. Finally, we proposed an experimental model that subjected an axon to more accurate strain. This model observed the process of axonal injury formation by detecting the same neuron before and after stretching. These results suggest that the strain-rate dependency of axonal tolerance is induced by a higher magnitude of loading strain and an experiment focusing on axonal strain is required for obtaining more detailed injury criteria for an axon.</p>","PeriodicalId":35289,"journal":{"name":"Stapp car crash journal","volume":"61 ","pages":"53-65"},"PeriodicalIF":0.0,"publicationDate":"2017-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"35788384","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Mike W J Arun, Prasannaah Hadagali, Klaus Driesslein, William Curry, Narayan Yoganandan, Frank A Pintar
{"title":"Biomechanics of Lumbar Motion-Segments in Dynamic Compression.","authors":"Mike W J Arun, Prasannaah Hadagali, Klaus Driesslein, William Curry, Narayan Yoganandan, Frank A Pintar","doi":"10.4271/2017-22-0001","DOIUrl":"https://doi.org/10.4271/2017-22-0001","url":null,"abstract":"<p><p>Recent epidemiology studies have reported increase in lumbar spine injuries in frontal crashes. Whole human body finite element models (FEHBM) are frequently used to delineate mechanisms of such injuries. However, the accuracy of these models in mimicking the response of human spine relies on the characterization data of the spine model. The current study set out to generate characterization data that can be input to FEHBM lumbar spine, to obtain biofidelic responses from the models. Twenty-five lumbar functional spinal units were tested under compressive loading. A hydraulic testing machine was used to load the superior ends of the specimens. A 75N load was placed on the superior PMMA to remove the laxity in the joint and mimic the physiological load. There were three loading sequences, namely, preconditioning, 0.5 m/s (non-injurious) and 1.0 m/s (failure). Forces and displacements were collected using six-axis load cell and VICON targets. In addition, acoustic signals were collected to identify the times of failures. Finally, response corridors were generated for the two speeds. To demonstrate the corridors, GHBMC FE model was simulated in frontal impact condition with the default and updated lumbar stiffness. Bi-linear trend was observed in the force versus displacement plots. In the 0.5 m/s tests, mean toe- and linear-region stiffnesses were 0.96±0.37 and 2.44±0.92 kN/mm. In 1.0 m/s tests, the toe and linear-region stiffnesses were 1.13±0.56 and 4.6±2.5 kN/mm. Lumbar joints demonstrated 2.5 times higher stiffness in the linear-region when the loading rate was increased by 0.5 m/s.</p>","PeriodicalId":35289,"journal":{"name":"Stapp car crash journal","volume":"61 ","pages":"1-25"},"PeriodicalIF":0.0,"publicationDate":"2017-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"35788382","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Association of Impact Velocity with Serious-injury and Fatality Risks to Cyclists in Commercial Truck-Cyclist Accidents.","authors":"Yasuhiro Matsui, Shoko Oikawa, Kazuhiro Sorimachi, Akira Imanishi, Takeshi Fujimura","doi":"10.4271/2017-22-0013","DOIUrl":"https://doi.org/10.4271/2017-22-0013","url":null,"abstract":"<p><p>This study aimed to clarify the relationship between truck-cyclist collision impact velocity and the serious-injury and fatality risks to cyclists, and to investigate the effects of road type and driving scenario on the frequency of cyclist fatalities due to collisions with vehicles. We used micro and macro truck-cyclist collision data from the Japanese Institute for Traffic Accident Research and Data Analysis (ITARDA) database. We classified vehicle type into five categories: heavy-duty trucks (gross vehicle weight [GVW] ≥11 × 10<sup>3</sup> kg [11 tons (t)], medium-duty trucks (5 × 10<sup>3</sup> kg [5 t] ≤ GVW < 11 × 10<sup>3</sup> kg [11 t]), light-duty trucks (GVW <5 × 10<sup>3</sup> kg [5 t]), box vans, and sedans. The fatality risk was ≤5% for light-duty trucks, box vans, and sedans at impact velocities ≤40 km/h and for medium-duty trucks at impact velocities ≤30 km/h. The fatality risk was 6% for heavy-duty trucks at impact velocities ≤10 km/h. Thus, the fatality risk appears strongly associated with vehicle class and impact velocity. The results revealed that a 10 km/h reduction in impact velocities could mitigate the severity of cyclist injuries at impact velocities ≥30 km/h for all five vehicle types. The frequency of cyclist fatalities at intersections with traffic signals involving heavy-duty trucks was significantly higher during daytime than that at nighttime. Fatalities involving vehicles making a left turn generally increased with vehicle weight. The frequency of cyclist fatalities involving vehicles making a left turn was the largest for heavy-duty trucks both during daytime (67.6%) and at nighttime (52.3%).</p>","PeriodicalId":35289,"journal":{"name":"Stapp car crash journal","volume":"61 ","pages":"355-371"},"PeriodicalIF":0.0,"publicationDate":"2017-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"35787394","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Julie Klima, Jian Kang, AnnMarie Meldrum, Steven Pankiewicz
{"title":"Neck Injury Response in High Vertical Accelerations and its Algorithmical Formalization to Mitigate Neck Injuries.","authors":"Julie Klima, Jian Kang, AnnMarie Meldrum, Steven Pankiewicz","doi":"10.4271/2017-22-0008","DOIUrl":"https://doi.org/10.4271/2017-22-0008","url":null,"abstract":"<p><p>Tank Automotive Research, Development and Engineering Center (TARDEC) conducted a comprehensive analysis of data collected during the evaluation of head and neck impact during injurious and non-injurious loading. This evaluation included impact velocity, helmet to roof clearance, and neck angle using a fully instrumented Hybrid III head and neck assembly. The results of this effort were compared against post mortem human subject (PMHS) data from similar testing conducted in conjunction with the Warrior Injury Assessment Manikin (WIAMan) program. The results identified the most severe helmet to roof clearance and neck angles. TARDEC used this knowledge as the foundation for continued research into head and neck impact injury mitigation through the use of passive technology and interior vehicle design.</p>","PeriodicalId":35289,"journal":{"name":"Stapp car crash journal","volume":"61 ","pages":"211-225"},"PeriodicalIF":0.0,"publicationDate":"2017-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"35788387","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Kent Butz, Chad Spurlock, Rajarshi Roy, Cameron Bell, Paul Barrett, Aaron Ward, Xudong Xiao, Allen Shirley, Colin Welch, Kevin Lister
{"title":"Development of the CAVEMAN Human Body Model: Validation of Lower Extremity Sub-Injurious Response to Vertical Accelerative Loading.","authors":"Kent Butz, Chad Spurlock, Rajarshi Roy, Cameron Bell, Paul Barrett, Aaron Ward, Xudong Xiao, Allen Shirley, Colin Welch, Kevin Lister","doi":"10.4271/2017-22-0007","DOIUrl":"https://doi.org/10.4271/2017-22-0007","url":null,"abstract":"<p><p>Improving injury prediction accuracy and fidelity for mounted Warfighters has become an area of focus for the U.S. military in response to improvised explosive device (IED) use in both Iraq and Afghanistan. Although the Hybrid III anthropomorphic test device (ATD) has historically been used for crew injury analysis, it is only capable of predicting a few select skeletal injuries. The Computational Anthropomorphic Virtual Experiment Man (CAVEMAN) human body model is being developed to expand the injury analysis capability to both skeletal and soft tissues. The CAVEMAN model is built upon the Zygote 50<sup>th</sup> percentile male human CAD model and uses a finite element modeling approach developed for high performance computing (HPC). The lower extremity subset of the CAVEMAN human body model presented herein includes: 28 bones, 26 muscles, 40 ligaments, fascia, cartilage and skin. Sensitivity studies have been conducted with the CAVEMAN lower extremity model to determine the structures critical for load transmission through the leg in the underbody blast (UBB) environment. An evaluation of the CAVEMAN lower extremity biofidelity was also carried out using 14 unique data sets derived by the Warrior Injury Assessment Manikin (WIAMan) program cadaveric lower leg testing. Extension of the CAVEMAN lower extremity model into anatomical tissue failure will provide additional injury prediction capabilities, beyond what is currently achievable using ATDs, to improve occupant survivability analyses within military vehicles.</p>","PeriodicalId":35289,"journal":{"name":"Stapp car crash journal","volume":"61 ","pages":"175-209"},"PeriodicalIF":0.0,"publicationDate":"2017-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.4271/2017-22-0007","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"35787390","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Biofidelity Evaluation of the THOR and Hybrid III 50<sup>th</sup> Percentile Male Frontal Impact Anthropomorphic Test Devices.","authors":"Daniel Parent, Matthew Craig, Kevin Moorhouse","doi":"10.4271/2017-22-0009","DOIUrl":"https://doi.org/10.4271/2017-22-0009","url":null,"abstract":"<p><p>The objective of this study is to present a quantitative comparison of the biofidelity of the THOR and Hybrid III 50<sup>th</sup> percentile male ATDs. Quantitative biofidelity was assessed using NHTSA's Biofidelity Ranking System in a total of 21 test conditions, including impacts to the head, face, neck, upper thorax, lower oblique thorax, upper abdomen, lower abdomen, femur, knee, lower leg, and whole-body sled tests to evaluate upper body kinematics and thoracic response under frontal and frontal oblique restraint loading. Biofidelity Ranking System scores for THOR were better (lower) than Hybrid III in 5 of 7 body regions for internal biofidelity and 6 of 7 body regions for external biofidelity. Nomenclature is presented to categorize the quantitative results, which show overall good internal and external biofidelity of the THOR compared to the good (internal) and marginal (external) biofidelity of the Hybrid III. The results highlight the excellent internal and external biofidelity of the THOR thorax.</p>","PeriodicalId":35289,"journal":{"name":"Stapp car crash journal","volume":"61 ","pages":"227-276"},"PeriodicalIF":0.0,"publicationDate":"2017-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"35787388","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Application of Extreme Value Theory to Crash Data Analysis.","authors":"Lan Xu, Guy Nusholtz","doi":"10.4271/2017-22-0011","DOIUrl":"https://doi.org/10.4271/2017-22-0011","url":null,"abstract":"<p><p>A parametric model obtained by fitting a set of data to a function generally uses a procedure such as maximum likelihood or least squares. In general this will generate the best estimate for the distribution of the data overall but will not necessarily generate a reasonable estimation for the tail of the distribution unless the function fitted resembles the underlying distribution function. A distribution function can represent an estimate that is significantly different from the actual tail data, while the bulk of the data is reasonably represented by the central part of the fitted distribution. Extreme value theory can be used to improve the predictive capabilities of the fitted function in the tail region. In this study the peak-over-threshold approach from the extreme value theory was utilized to show that it is possible to obtain a better fit of the tail of a distribution than the procedures that use the entire distribution only. Additional constraints, on the current use of the extreme value approach with respect to the selection of the threshold (an estimate of the beginning of the tail region) that minimize the sensitivity to individual data samples associated with the tail section as well as contamination from the central distribution are used. Once the threshold is determined, the maximum likelihood method was used to fit the exceedances with the Generalized Pareto Distribution to obtain the tail distribution. The approach was then used in the analysis of airbag inflator pressure data from tank tests, crash velocity distribution and mass distribution from the field crash data (NASS). From the examples, the extreme (tail) distributions were better estimated with the Generalized Pareto Distribution, than a single overall distribution, along with the probability of the occurrence for a given extreme value, or a rare observation such as a high speed crash. It was concluded that the peak-over-threshold approach from extreme value theory can be a useful tool in the vehicle crash, biomechanics and injury tolerance data analysis and in estimation of the occurrence probability of an extreme phenomenon given a set of accurate observations.</p>","PeriodicalId":35289,"journal":{"name":"Stapp car crash journal","volume":"61 ","pages":"287-298"},"PeriodicalIF":0.0,"publicationDate":"2017-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"35787393","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Sajal Chirvi, Frank Pintar, Narayan Yoganandan, Anjishnu Banerjee, Mike Schlick, William Curry, Liming Voo
{"title":"Human Foot-Ankle Injuries and Associated Risk Curves from Under Body Blast Loading Conditions.","authors":"Sajal Chirvi, Frank Pintar, Narayan Yoganandan, Anjishnu Banerjee, Mike Schlick, William Curry, Liming Voo","doi":"10.4271/2017-22-0006","DOIUrl":"https://doi.org/10.4271/2017-22-0006","url":null,"abstract":"<p><p>Under body blast (UBB) loading to military transport vehicles is known to cause foot-ankle fractures to occupants due to energy transfer from the vehicle floor to the feet of the soldier. The soldier posture, the proximity of the event with respect to the soldier, the personal protective equipment (PPE) and age/sex of the soldier are some variables that can influence injury severity and injury patterns. Recently conducted experiments to simulate the loading environment to the human foot/ankle in UBB events (~5ms rise time) with variables such as posture, age and PPE were used for the current study. The objective of this study was to determine statistically if these variables affected the primary injury predictors, and develop injury risk curves. Fifty belowknee post mortem human surrogate (PMHS) legs were used for statistical analysis. Injuries to specimens involved isolated and multiple fractures of varying severity. The Sanders classification was used to grade calcaneus severity and the AO/OTA classification for distal tibia fracture. Injury risk curves were developed using survival regression analysis and covariates were included whenever statistically significant (p<0.05). With peak force as the injury predictor and age and boot as covariates, the model was statistically significant. However, boot use changed the pattern of injury from predominately calcaneus to predominantly tibia. Also, a severity based risk curve showed tolerance differences between calcaneus (minor/major) and tibia (severity-I/ severity- II) injuries. The tibia demonstrated higher tolerance as compared to either minor or major calcaneus injury. These findings can play a vital role in development of safety systems to mitigate injuries to the occupant.</p>","PeriodicalId":35289,"journal":{"name":"Stapp car crash journal","volume":"61 ","pages":"157-173"},"PeriodicalIF":0.0,"publicationDate":"2017-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"35788386","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Optimal Specifications for the Advanced Pedestrian Legform Impactor.","authors":"Takahiro Isshiki, Jacobo Antona-Makoshi, Atsuhiro Konosu, Yukou Takahashi","doi":"10.4271/2017-22-0014","DOIUrl":"https://doi.org/10.4271/2017-22-0014","url":null,"abstract":"<p><p>This study addresses the virtual optimization of the technical specifications for a recently developed Advanced Pedestrian Legform Impactor (aPLI). The aPLI incorporates a number of enhancements for improved lower limb injury predictability with respect to its predecessor, the FlexPLI. It also incorporates an attached Simplified Upper Body Part (SUBP) that enables the impactor's applicability to evaluate pedestrian's lower limb injury risk also with high-bumper cars. The response surface methodology was applied to optimize both the aPLI's lower limb and SUBP specifications, while imposing a total mass upper limit of 25 kg that complies with international standards for maximum weight lifting allowed for a single operator in the laboratory setting. All parameters were virtually optimized considering variable interaction, which proved critical to avoid misleading specifications. The results from this study can be used to construct physical aPLIs that are expected to be used in future car-to-pedestrian crash safety testing programs worldwide.</p>","PeriodicalId":35289,"journal":{"name":"Stapp car crash journal","volume":"61 ","pages":"373-395"},"PeriodicalIF":0.0,"publicationDate":"2017-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"35788790","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Jingwen Hu, Matthew P Reed, Jonathan D Rupp, Kurt Fischer, Paul Lange, Angelo Adler
{"title":"Optimizing Seat Belt and Airbag Designs for Rear Seat Occupant Protection in Frontal Crashes.","authors":"Jingwen Hu, Matthew P Reed, Jonathan D Rupp, Kurt Fischer, Paul Lange, Angelo Adler","doi":"10.4271/2017-22-0004","DOIUrl":"https://doi.org/10.4271/2017-22-0004","url":null,"abstract":"Recent field data have shown that the occupant protection in vehicle rear seats failed to keep pace with advances in the front seats likely due to the lack of advanced safety technologies. The objective of this study was to optimize advanced restraint systems for protecting rear seat occupants with a range of body sizes under different frontal crash pulses. Three series of sled tests (baseline tests, advanced restraint trial tests, and final tests), MADYMO model validations against a subset of the sled tests, and design optimizations using the validated models were conducted to investigate rear seat occupant protection with 4 Anthropomorphic Test Devices (ATDs) and 2 crash pulses. The sled tests and computer simulations were conducted with a variety of restraint systems including the baseline rear-seat 3-point belt, 3-point belts with a pre-tensioner, load limiter, dynamic locking tongue, 4-point belts, inflatable belts, Bag in Roof (BiR) concept, and Self Conforming Rear seat Air Bag (SCaRAB) concept. The results of the first two sled series demonstrated that the baseline 3-point belt system are associated with many injury measures exceeding injury assessment reference values (IARVs); showed the significance of crash pulse and occupant size in predicting injury risks; and verified the potential need of advanced restraint features for better protecting the rear-seat occupants. Good correlations between the tests and simulations were achieved through a combination of optimization and manual fine-tuning, as determined by a correlation method. Parametric simulations showed that optimized belt-only designs (3-point belt with pre-tensioner and load limiter) met all of the IARVs under the soft crash pulse but not the severe crash pulse, while the optimized belt and SCaRAB design met all the IARVs under both the soft and severe crash pulses. Two physical prototype restraint systems, namely an \"advanced-belt only\" design and an \"advanced-belt and SCaRAB\" design, were then tested in the final sled series. With the soft crash pulse, both advanced restraint systems were able to reduce all the injury measures below the IARVs for all four ATDs. Both advanced restraint systems also effectively reduced almost all the injury measures for all ATDs under the severe crash pulse, except for the THOR. The design with the advanced-belt and SCaRAB generally provided lower injury measures than those using the advanced belt-only design. This study highlighted the potential benefit of using advanced seatbelt and airbag systems for rear-seat occupant protection in frontal crashes.","PeriodicalId":35289,"journal":{"name":"Stapp car crash journal","volume":"61 ","pages":"67-100"},"PeriodicalIF":0.0,"publicationDate":"2017-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"35788381","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}