Nicholas Shewchenko - Academia.edu (original) (raw)

Papers by Nicholas Shewchenko

Research paper thumbnail of Crash Injury Biomechanics: Proceedings of a Conference Held in Adelaide, South Australia, 19-21 July 1992

Abstract: The following papers were presented at the conference: The importance of biomechanics i... more Abstract: The following papers were presented at the conference: The importance of biomechanics in the development of vehicle safety (Digges, K); Impact biomechanics for safety improvement (Cesari, D); Need for the study of clarifying injury mechanisms based ...

Research paper thumbnail of Heading in football. Part 2: Biomechanics of ball heading and head response

British Journal of Sports Medicine, Aug 1, 2005

Research paper thumbnail of Biofidelity Improvements to the Hybrid III Neck

Proceedings of the 14th International Technical Conference on the Enhanced Safety of Vehicles (ESV), 1995

This paper describes the steps taken to improve the biomechanical fidelity of the neck of the fro... more This paper describes the steps taken to improve the biomechanical fidelity of the neck of the frontal impact test dummy, the Hybrid III, to make it more suitable for motorcycle crash testing. On the basis of volunteer and cadaver studies, several refinements have been made to the Hybrid Ill neck. These include changes to the range of motion of the head/neck joint and its means of static adjustment, a change in the neck stiffness in flexion/extension, and the improvement of torsional biofidelity. The purpose of these modifications is to improve the response characteristics of the neck: (1) to allow the dummy to be used in a larger range of postures than the standard; and (2) to make the neck and head respond more realistically during the testing of current motorcycle safety systems. (A) For the covering abstract of the conference see IRRD 894848.

Research paper thumbnail of Tolerance limits for mild traumatic brain injury derived from numerical head impact replication

Research paper thumbnail of Design of a motorcyclist anthropometric test device

Proceedings of the 12th International Technical Conference on Experimental Safety Vehicles (ESV), 1989

Research paper thumbnail of A New Biomechanical Assessment of Mild Traumatic Brain Injury. Part I: Methodology

This paper follows Part I that was presented at the 1999 IRCOBI Conference. A methodology, descri... more This paper follows Part I that was presented at the 1999 IRCOBI Conference. A methodology, described in Part 1, has been developed that permits the reconstruction of certain incidents that occur in American football. Twenty-four cases of helmeted head impact, for which concussion was diagnosed in 9 cases, have been replicated with Hybrid III ATDs. Rigid body translational and rotational head accelerations have been measured in each case. Correlations between head injury and head kinematics have been sought. Peak translational and peak rotational acceleration and velocity, HIC and the Gadd SI, as well as the GAMBIT have all been considered. A new approach employing the maximum value of the global rate of energy dissipation has proven to provide the best correlation between concussion probability and head kinematics. This new relationship provides a basis for a new head injury criterion function, the HEAD IMPACT POWER.

Research paper thumbnail of Concussion in Professional Football

Neurosurgery, Sep 1, 2006

ABSTRACT

Research paper thumbnail of Head, neck, and body coupling in reconstructions of helmeted head impacts

A mathematical modeling study is conducted to investigate neck coupling in helmeted head impacts.... more A mathematical modeling study is conducted to investigate neck coupling in helmeted head impacts. The main objective of the study is to provide direction for the experimental reconstruction of American football player impacts. Head responses are compared in MADYMO simulations of various impact scenarios without neck coupling, with an improved human neck model, and with a Hybrid-III neck model. The human neck model is a continued development of an existing neck model, with improved multi-directional biofidelity. Also the helmet model has substantial effect on the interpretation of the simulation results, and a model of an American football helmet is developed. In the simulated impact scenarios, linear head accelerations show limited change as a result of neck coupling, but angular head accelerations change drastically depending on whether or not a neck is included in the model. Effects of body mass on head accelerations are limited for the impact conditions simulated in this study. This study shows that neck coupling should be accounted for if head linear and angular accelerations obtained from accident reconstructions are to be used to establish human tolerance.

Research paper thumbnail of Research to Evaluate Safety Technologies for Vulnerable Fuel Tanks

PROCEEDINGS OF 18TH INTERNATIONAL TECHNICAL CONFERENCE ON THE ENHANCED SAFETY OF VEHICLES, HELD NAGOYA, JAPAN, 19-22 MAY 2003, May 1, 2003

... Kennerly Digges Automotive Safety Research Institute USA Edmund Fournier Matthew KeownJim Kot... more ... Kennerly Digges Automotive Safety Research Institute USA Edmund Fournier Matthew KeownJim Kot Nicholas Shewchenko Biokinetics & Associated, Ltd. ... Break-away couplings in the fuel lines, a flapper valve in the filler tube and shielding of vulnerable fuel lines were tested ...

Research paper thumbnail of Heading in football. Part 3: Effect of ball properties on head response

British Journal of Sports Medicine, Aug 1, 2005

Research paper thumbnail of The Skull and Brain

CRC Press eBooks, May 22, 2017

Research paper thumbnail of Development of an infant impact headform

Research paper thumbnail of A Practical Ballistic Yaw Sensor

It is widely recognized that angled or yawed projectile impacts on armour can affect the perceive... more It is widely recognized that angled or yawed projectile impacts on armour can affect the perceived performance due to changes in projectile’s interactions with the armour-. Furthermore, spurious results and greater uncertainty in armour performance can result from variations in yaw angles if not accounted for. While many ballistic test standards limit the allowable incident angle, its measurement has long been accomplished with yaw cards despite having poor precision and possible effect on trajectory. This paper describes the development of a non-contact ballistic yaw sensor for small calibre ammunition and fragment simulating projectiles that meets the requirements of ballistic standards while providing much greater precision and ease of use over that of yaw cards. The use of computer vision methods combined with LED lighting has resulted in a system that is quick and simple to use. The setup, operation, data analysis and accuracy are described with examples of its use.

Research paper thumbnail of The Skull and Brain : Test Methods, Behind Armour Blunt Trauma and Helmet Design

Research paper thumbnail of Uncertainty: What Does It Mean for Ballistic Chronographs?

Proceedings of the 32nd International Symposium on Ballistics, May 9, 2022

Two of the most cited performance properties of ballistic armour systems that characterize resist... more Two of the most cited performance properties of ballistic armour systems that characterize resistance to penetration are the ballistic limit (V50) and the proof velocity (Vproof). It is therefore critical that the test velocities are measured with a high degree of certainty for gaining confidence in the ballistic performance assessment for research and development, demonstration of compliance, and quality control purposes (i.e., ISO 17025). Unfortunately, common ballistic testing standards (NIJ 0101.06, ASTM E3062, etc.) do not provide sufficient clarity regarding contributors to consider, coverage factors, or interpretation of stated accuracy limits, leaving significant room for interpretation. This work applies principles of the Guide to the expression of uncertainty in measurement (GUM) to a COTS ballistic chronograph (SpeedTube™) to form a basis for discussions regarding interpretation of standards and the need for standards to use language consistent with the International Vocabulary of Metrology (VIM) for the benefit of researchers, manufacturers, and test facilities.

Research paper thumbnail of The Effect of Anthropomorphic Test Device Lower Leg Surrogate Selection on Impact Mitigating System Evaluation in Low- and High-Rate Loading Conditions

Military Medicine, Sep 1, 2017

Introduction: The lower legs are at risk of substantial injury during events such as frontal auto... more Introduction: The lower legs are at risk of substantial injury during events such as frontal automotive crashes and antivehicular mine blasts. Loading to occupants can be assessed using an instrumented anthropomorphic test device (ATD), whose measurements can be compared to established injury criteria. NATO's AEP-55 STANAG 4569 recognizes two surrogates for lower leg injury assessments from impacts with intruding floor pans resulting from underbelly blast loads; (1) the rigid Hybrid III instrumented lower leg, and; (2) the compliant MILitary Lower eXtremity (MIL-LX). The established injury criterion for the Hybrid III leg specifies a maximum lower tibia compressive load of 5.4 kN, whereas the MIL-LX limit is 2.6 kN measured at the upper tibia for similar injury severity levels. The difference in compliance between the two legs could affect the evaluation of protection levels, resulting in an over-or underestimation of the force attenuation of energy attenuating (EA) floor mats. Materials and Methods: The responses of the two lower leg surrogates were evaluated at impact velocities up to 12 m/s, representing floor intrusions during antivehicle mine blasts. An air cannon was used to accelerate a rigid or padded floor plate into the sole of the surrogate lower legs, loading them axially, in order to assess the protective capability of commercial EA floor mats. The peak load from the lower and upper load cells in the Hybrid III and MIL-LX legs were compared to identify at what point their respective injury criteria would be exceeded in both the padded and unpadded conditions. Results: Comparisons of the surrogate legs' responses resulted in different evaluations of risk, with the Hybrid III leg exceeding its limit at an impact speed of 6.0 m/s, and the MIL-LX exceeding its limit at 5.5 m/s (for tests including an EA product). Furthermore, the inclusion of an EA mat had a greater relative protective effect on the Hybrid III than the MIL-LX leg, with padding reducing the force to 17 to 34% of the unpadded condition for the Hybrid III, versus 67 to 89% of the unpadded condition for the MIL-LX. The load reduction was found to be velocity dependent for both surrogates. Conclusion: These results indicate that the two surrogates are not equivalent in their assessment of protective capability. Therefore, the selection of ATD leg for testing of EA mats (and other protective devices) will influence the evaluation of these systems, and more robust metrics are required to identify which is the most appropriate surrogate for evaluating injury to the lower limb.

Research paper thumbnail of Heading in football. Part 1: Development of biomechanical methods to investigate head response

British Journal of Sports Medicine, Aug 1, 2005

Research paper thumbnail of Biomechanical investigation of head impacts in football

British Journal of Sports Medicine, Aug 1, 2005

This study sought to measure the head accelerations induced from upper extremity to head and head... more This study sought to measure the head accelerations induced from upper extremity to head and head to head impact during the game of football and relate this to the risk of mild traumatic brain injury using the Head Impact Power (HIP) index. Furthermore, measurement of upper neck forces and torques will indicate the potential for serious neck injury. More stringent rules or punitive sanctions may be warranted for intentional impact by the upper extremity or head during game play. Methods: Game video of 62 cases of head impact (38% caused by the upper extremity and 30% by the head of the opposing player) was provided by F-MARC. Video analysis revealed the typical impact configurations and representative impact speeds. Upper extremity impacts of elbow strike and lateral hand strike were re-enacted in the laboratory by five volunteer football players striking an instrumented Hybrid III pedestrian model crash test manikin. Head to head impacts were re-enacted using two instrumented test manikins. Results: Elbow to head impacts (1.7-4.6 m/s) and lateral hand strikes (5.2-9.3 m/s) resulted in low risk of concussion (,5%) and severe neck injury (,5%). Head to head impacts (1.5-3.0 m/s) resulted in high concussion risk (up to 67%) but low risk of severe neck injury (,5%). Conclusion: The laboratory simulations suggest little risk of concussion based on head accelerations and maximum HIP. There is no biomechanical justification for harsher penalties in this regard. However, deliberate use of the head to impact another player's head poses a high risk of concussion, and justifies a harsher position by regulatory bodies. In either case the risk of serious neck injury is very low.

Research paper thumbnail of Uncertainty: What Does It Mean for Ballistic Chronographs?

Proceedings of the 32nd International Symposium on Ballistics, May 9, 2022

Research paper thumbnail of Development of an infant impact headform

Research paper thumbnail of Crash Injury Biomechanics: Proceedings of a Conference Held in Adelaide, South Australia, 19-21 July 1992

Abstract: The following papers were presented at the conference: The importance of biomechanics i... more Abstract: The following papers were presented at the conference: The importance of biomechanics in the development of vehicle safety (Digges, K); Impact biomechanics for safety improvement (Cesari, D); Need for the study of clarifying injury mechanisms based ...

Research paper thumbnail of Heading in football. Part 2: Biomechanics of ball heading and head response

British Journal of Sports Medicine, Aug 1, 2005

Research paper thumbnail of Biofidelity Improvements to the Hybrid III Neck

Proceedings of the 14th International Technical Conference on the Enhanced Safety of Vehicles (ESV), 1995

This paper describes the steps taken to improve the biomechanical fidelity of the neck of the fro... more This paper describes the steps taken to improve the biomechanical fidelity of the neck of the frontal impact test dummy, the Hybrid III, to make it more suitable for motorcycle crash testing. On the basis of volunteer and cadaver studies, several refinements have been made to the Hybrid Ill neck. These include changes to the range of motion of the head/neck joint and its means of static adjustment, a change in the neck stiffness in flexion/extension, and the improvement of torsional biofidelity. The purpose of these modifications is to improve the response characteristics of the neck: (1) to allow the dummy to be used in a larger range of postures than the standard; and (2) to make the neck and head respond more realistically during the testing of current motorcycle safety systems. (A) For the covering abstract of the conference see IRRD 894848.

Research paper thumbnail of Tolerance limits for mild traumatic brain injury derived from numerical head impact replication

Research paper thumbnail of Design of a motorcyclist anthropometric test device

Proceedings of the 12th International Technical Conference on Experimental Safety Vehicles (ESV), 1989

Research paper thumbnail of A New Biomechanical Assessment of Mild Traumatic Brain Injury. Part I: Methodology

This paper follows Part I that was presented at the 1999 IRCOBI Conference. A methodology, descri... more This paper follows Part I that was presented at the 1999 IRCOBI Conference. A methodology, described in Part 1, has been developed that permits the reconstruction of certain incidents that occur in American football. Twenty-four cases of helmeted head impact, for which concussion was diagnosed in 9 cases, have been replicated with Hybrid III ATDs. Rigid body translational and rotational head accelerations have been measured in each case. Correlations between head injury and head kinematics have been sought. Peak translational and peak rotational acceleration and velocity, HIC and the Gadd SI, as well as the GAMBIT have all been considered. A new approach employing the maximum value of the global rate of energy dissipation has proven to provide the best correlation between concussion probability and head kinematics. This new relationship provides a basis for a new head injury criterion function, the HEAD IMPACT POWER.

Research paper thumbnail of Concussion in Professional Football

Neurosurgery, Sep 1, 2006

ABSTRACT

Research paper thumbnail of Head, neck, and body coupling in reconstructions of helmeted head impacts

A mathematical modeling study is conducted to investigate neck coupling in helmeted head impacts.... more A mathematical modeling study is conducted to investigate neck coupling in helmeted head impacts. The main objective of the study is to provide direction for the experimental reconstruction of American football player impacts. Head responses are compared in MADYMO simulations of various impact scenarios without neck coupling, with an improved human neck model, and with a Hybrid-III neck model. The human neck model is a continued development of an existing neck model, with improved multi-directional biofidelity. Also the helmet model has substantial effect on the interpretation of the simulation results, and a model of an American football helmet is developed. In the simulated impact scenarios, linear head accelerations show limited change as a result of neck coupling, but angular head accelerations change drastically depending on whether or not a neck is included in the model. Effects of body mass on head accelerations are limited for the impact conditions simulated in this study. This study shows that neck coupling should be accounted for if head linear and angular accelerations obtained from accident reconstructions are to be used to establish human tolerance.

Research paper thumbnail of Research to Evaluate Safety Technologies for Vulnerable Fuel Tanks

PROCEEDINGS OF 18TH INTERNATIONAL TECHNICAL CONFERENCE ON THE ENHANCED SAFETY OF VEHICLES, HELD NAGOYA, JAPAN, 19-22 MAY 2003, May 1, 2003

... Kennerly Digges Automotive Safety Research Institute USA Edmund Fournier Matthew KeownJim Kot... more ... Kennerly Digges Automotive Safety Research Institute USA Edmund Fournier Matthew KeownJim Kot Nicholas Shewchenko Biokinetics & Associated, Ltd. ... Break-away couplings in the fuel lines, a flapper valve in the filler tube and shielding of vulnerable fuel lines were tested ...

Research paper thumbnail of Heading in football. Part 3: Effect of ball properties on head response

British Journal of Sports Medicine, Aug 1, 2005

Research paper thumbnail of The Skull and Brain

CRC Press eBooks, May 22, 2017

Research paper thumbnail of Development of an infant impact headform

Research paper thumbnail of A Practical Ballistic Yaw Sensor

It is widely recognized that angled or yawed projectile impacts on armour can affect the perceive... more It is widely recognized that angled or yawed projectile impacts on armour can affect the perceived performance due to changes in projectile’s interactions with the armour-. Furthermore, spurious results and greater uncertainty in armour performance can result from variations in yaw angles if not accounted for. While many ballistic test standards limit the allowable incident angle, its measurement has long been accomplished with yaw cards despite having poor precision and possible effect on trajectory. This paper describes the development of a non-contact ballistic yaw sensor for small calibre ammunition and fragment simulating projectiles that meets the requirements of ballistic standards while providing much greater precision and ease of use over that of yaw cards. The use of computer vision methods combined with LED lighting has resulted in a system that is quick and simple to use. The setup, operation, data analysis and accuracy are described with examples of its use.

Research paper thumbnail of The Skull and Brain : Test Methods, Behind Armour Blunt Trauma and Helmet Design

Research paper thumbnail of Uncertainty: What Does It Mean for Ballistic Chronographs?

Proceedings of the 32nd International Symposium on Ballistics, May 9, 2022

Two of the most cited performance properties of ballistic armour systems that characterize resist... more Two of the most cited performance properties of ballistic armour systems that characterize resistance to penetration are the ballistic limit (V50) and the proof velocity (Vproof). It is therefore critical that the test velocities are measured with a high degree of certainty for gaining confidence in the ballistic performance assessment for research and development, demonstration of compliance, and quality control purposes (i.e., ISO 17025). Unfortunately, common ballistic testing standards (NIJ 0101.06, ASTM E3062, etc.) do not provide sufficient clarity regarding contributors to consider, coverage factors, or interpretation of stated accuracy limits, leaving significant room for interpretation. This work applies principles of the Guide to the expression of uncertainty in measurement (GUM) to a COTS ballistic chronograph (SpeedTube™) to form a basis for discussions regarding interpretation of standards and the need for standards to use language consistent with the International Vocabulary of Metrology (VIM) for the benefit of researchers, manufacturers, and test facilities.

Research paper thumbnail of The Effect of Anthropomorphic Test Device Lower Leg Surrogate Selection on Impact Mitigating System Evaluation in Low- and High-Rate Loading Conditions

Military Medicine, Sep 1, 2017

Introduction: The lower legs are at risk of substantial injury during events such as frontal auto... more Introduction: The lower legs are at risk of substantial injury during events such as frontal automotive crashes and antivehicular mine blasts. Loading to occupants can be assessed using an instrumented anthropomorphic test device (ATD), whose measurements can be compared to established injury criteria. NATO's AEP-55 STANAG 4569 recognizes two surrogates for lower leg injury assessments from impacts with intruding floor pans resulting from underbelly blast loads; (1) the rigid Hybrid III instrumented lower leg, and; (2) the compliant MILitary Lower eXtremity (MIL-LX). The established injury criterion for the Hybrid III leg specifies a maximum lower tibia compressive load of 5.4 kN, whereas the MIL-LX limit is 2.6 kN measured at the upper tibia for similar injury severity levels. The difference in compliance between the two legs could affect the evaluation of protection levels, resulting in an over-or underestimation of the force attenuation of energy attenuating (EA) floor mats. Materials and Methods: The responses of the two lower leg surrogates were evaluated at impact velocities up to 12 m/s, representing floor intrusions during antivehicle mine blasts. An air cannon was used to accelerate a rigid or padded floor plate into the sole of the surrogate lower legs, loading them axially, in order to assess the protective capability of commercial EA floor mats. The peak load from the lower and upper load cells in the Hybrid III and MIL-LX legs were compared to identify at what point their respective injury criteria would be exceeded in both the padded and unpadded conditions. Results: Comparisons of the surrogate legs' responses resulted in different evaluations of risk, with the Hybrid III leg exceeding its limit at an impact speed of 6.0 m/s, and the MIL-LX exceeding its limit at 5.5 m/s (for tests including an EA product). Furthermore, the inclusion of an EA mat had a greater relative protective effect on the Hybrid III than the MIL-LX leg, with padding reducing the force to 17 to 34% of the unpadded condition for the Hybrid III, versus 67 to 89% of the unpadded condition for the MIL-LX. The load reduction was found to be velocity dependent for both surrogates. Conclusion: These results indicate that the two surrogates are not equivalent in their assessment of protective capability. Therefore, the selection of ATD leg for testing of EA mats (and other protective devices) will influence the evaluation of these systems, and more robust metrics are required to identify which is the most appropriate surrogate for evaluating injury to the lower limb.

Research paper thumbnail of Heading in football. Part 1: Development of biomechanical methods to investigate head response

British Journal of Sports Medicine, Aug 1, 2005

Research paper thumbnail of Biomechanical investigation of head impacts in football

British Journal of Sports Medicine, Aug 1, 2005

This study sought to measure the head accelerations induced from upper extremity to head and head... more This study sought to measure the head accelerations induced from upper extremity to head and head to head impact during the game of football and relate this to the risk of mild traumatic brain injury using the Head Impact Power (HIP) index. Furthermore, measurement of upper neck forces and torques will indicate the potential for serious neck injury. More stringent rules or punitive sanctions may be warranted for intentional impact by the upper extremity or head during game play. Methods: Game video of 62 cases of head impact (38% caused by the upper extremity and 30% by the head of the opposing player) was provided by F-MARC. Video analysis revealed the typical impact configurations and representative impact speeds. Upper extremity impacts of elbow strike and lateral hand strike were re-enacted in the laboratory by five volunteer football players striking an instrumented Hybrid III pedestrian model crash test manikin. Head to head impacts were re-enacted using two instrumented test manikins. Results: Elbow to head impacts (1.7-4.6 m/s) and lateral hand strikes (5.2-9.3 m/s) resulted in low risk of concussion (,5%) and severe neck injury (,5%). Head to head impacts (1.5-3.0 m/s) resulted in high concussion risk (up to 67%) but low risk of severe neck injury (,5%). Conclusion: The laboratory simulations suggest little risk of concussion based on head accelerations and maximum HIP. There is no biomechanical justification for harsher penalties in this regard. However, deliberate use of the head to impact another player's head poses a high risk of concussion, and justifies a harsher position by regulatory bodies. In either case the risk of serious neck injury is very low.

Research paper thumbnail of Uncertainty: What Does It Mean for Ballistic Chronographs?

Proceedings of the 32nd International Symposium on Ballistics, May 9, 2022

Research paper thumbnail of Development of an infant impact headform