scholarly journals Dynamic Responses of Female Volunteers in Rear Impact Sled Tests at Two Head Restraint Distances

2021 ◽  
Vol 9 ◽  
Author(s):  
Anna Carlsson ◽  
Stefan Horion ◽  
Johan Davidsson ◽  
Sylvia Schick ◽  
Astrid Linder ◽  
...  
Keyword(s):  
Dynamic Responses ◽  
Accelerometer Data ◽  
Velocity Change ◽  
Test Configuration ◽  
Head Restraint ◽  
Rear Impact ◽  
Injury Criteria ◽  
Time Histories ◽  
Test Event ◽  
Angular Displacements

The objective of this study was to assess the biomechanical and kinematic responses of female volunteers with two different head restraint (HR) configurations when exposed to a low-speed rear loading environment. A series of rear impact sled tests comprising eight belted, near 50th percentile female volunteers, seated on a simplified laboratory seat, was performed with a mean sled acceleration of 2.1 g and a velocity change of 6.8 km/h. Each volunteer underwent two tests; the first test configuration, HR10, was performed at the initial HR distance ∼10 cm and the second test configuration, HR15, was performed at ∼15 cm. Time histories, peak values and their timing were derived from accelerometer data and video analysis, and response corridors were also generated. The results were separated into three different categories, HR10C (N = 8), HR15C (N = 6), and HR15NC (N = 2), based on: (1) the targeted initial HR distance [10 cm or 15 cm] and (2) whether the volunteers’ head had made contact with the HR [Contact (C) or No Contact (NC)] during the test event. The results in the three categories deviated significantly. The greatest differences were found for the average peak head angular displacements, ranging from 10° to 64°. Furthermore, the average neck injury criteria (NIC) value was 22% lower in HR10C (3.9 m2/s2), and 49% greater in HR15NC (7.4 m2/s2) in comparison to HR15C (5.0 m2/s2). This study supplies new data suitable for validation of mechanical or mathematical models of a 50th percentile female. A model of a 50th percentile female remains to be developed and is urgently required to complement the average male models to enhance equality in safety assessments. Hence, it is important that future protection systems are developed and evaluated with female properties taken into consideration too. It is likely that the HR15 test configuration is close to the limit for avoiding HR contact for this specific seat setup. Using both datasets (HR15C and HR15NC), each with its corresponding HR contact condition, will be possible in future dummy or model evaluation.

Effect of Head Restraint Position and Neck Injury Criteria in Rear Impact

2002 ◽  
Author(s):  
John DeRosia ◽  
Narayan Yoganandan ◽  
Frank A. Pintar
Keyword(s):  
Motor Vehicle ◽  
Vehicle Safety ◽  
Bending Moments ◽  
Safety Standards ◽  
Acceleration Pulse ◽  
Head Restraint ◽  
Rear Impact ◽  
Injury Criteria ◽  
Hybrid Iii ◽  
Impact Acceleration

The objective of this study was to determine the forces and bending moments at the top of the Hybrid III dummy neck secondary to rear impact acceleration and evaluate the various proposed injury criteria. Rear impact sled tests were conducted by applying the Federal Motor Vehicle Safety Standards FMVSS 202 acceleration pulse. Differing positions of the head restraint in terms of height (750 and 800 mm) and backset (zero, 50, and 100 mm) were used to determine the axial and shear forces, bending moments, and injury criteria (NIC, Nij, and Nkm). The time sequence of attainment of these parameters was determined along with peak values.

Comparison on General Track Spectrum for Chinese Main Railway Lines and Track Spectrum of American Railway Lines

2011 ◽  
Vol 250-253 ◽  
pp. 3822-3826 ◽  
Author(s):  
Xian Mai Chen ◽  
Xia Xin Tao ◽  
Gao Hang Cui ◽  
Fu Tong Wang
Keyword(s):  
Dynamic Performance ◽  
Dynamic Responses ◽  
Wave Band ◽  
Wheel Load ◽  
Railway Line ◽  
Acceleration Rate ◽  
Time Histories ◽  
Railway System ◽  
Dynamic Performances ◽  
Track Irregularity

The general track spectrum of Chinese main railway lines (ChinaRLS) and the track spectrum of American railway lines (AmericaRLS) are compared in terms of character of frequency domain, statistical property of time domain samples and dynamic performance. That the wavelength range of the ChinaRLS, which is characterized by the three levels according to the class of railway line, is less than AmericaRLS at common wave band of 1~50m is calculated. Simultaneously, the mean square values of two kinds of track spectra are provided at the detrimental wave bands of 5~10m, 10~20m, and so on. The time-histories of ChinaRLS and AmericaRLS are simulated according to the trigonometric method, and the digital statistical nature of simulated time samples is analyzed. With inputting the two kinds of time-histories into the vehicle-railway system, the comparative analysis of the two kinds of dynamic performances for ChinaRLS and AmericaRLS is done in terms of car body acceleration, rate of wheel load reduction, wheel/rail force, and the dynamic responses of track structure. The result shows that ChinaRLS can characterize the feature of the Chinese track irregularity better than AmericaRLS, the track irregularity with the ChinaRLS of 200km/h is superior to the AmericaRLS, and the track irregularity with the ChinaRLS of 160km/h corresponds to with the sixth of AmericaRLS.

Load-Based Lower Neck Injury Criteria for Females from Rear Impact from Cadaver Experiments

2017 ◽  
Vol 45 (5) ◽  
pp. 1194-1203 ◽  
Author(s):  
Narayan Yoganandan ◽  
Frank A. Pintar ◽  
Anjishnu Banerjee
Keyword(s):  
Neck Injury ◽  
Rear Impact ◽  
Injury Criteria ◽  
Lower Neck

Experimental Investigation of the Modal Response of a Rail Span during and after Wheel Passage

2020 ◽  
Vol 2674 (12) ◽  
pp. 15-24
Author(s):  
Korkut Kaynardag ◽  
Giuseppe Battaglia ◽  
Chi Yang ◽  
Salvatore Salamone
Keyword(s):  
Field Tests ◽  
Dynamic Responses ◽  
Modal Parameters ◽  
Moving Loads ◽  
Additional Information ◽  
Time Histories ◽  
Propagation Parameters ◽  
Displacement Force ◽  
Force Time ◽  
Comparison Of The Results

This paper examines the vibrations of a rail span (rail section between two consecutive sleepers) during and after the passage of a rail car’s wheel as well as under impact hammer excitation. In literature, the dynamic response of railway tracks under moving loads has been studied extensively. Many of these studies focus on the responses in relation to displacement/force-time histories and wave propagation parameters. These responses are investigated for the time instants when rail car wheels transverse over the rail spans of interest. In this context, an investigation of responses in relation to modal parameters during and after moving loads might provide additional information. Such information can be used to examine how the loading and additional masses induced by the moving wheels affect the dynamic responses. To this end, field tests were carried out at Transportation Technology Center Inc. (TTCI) facility in Colorado, U.S. First, to find the flexural modes of a rail span under no loading, data was collected from three accelerometers placed on the span under vertical impact hammer excitation. Next, the accelerometers were placed underneath the rail span, and data was collected while a rail car traveled over the span. The signal segments corresponding to during and after a wheel passage were analyzed for the identification of modal parameters. The comparison of the results demonstrated that the frequencies of the rail span increased as the loading induced by the wheel increased.

scholarly journals A Procedure to Select Earthquake Time Histories for Deterministic Seismic Hazard Analysis: Case Studies of Major Cities in Taiwan

2017 ◽  
Author(s):  
Duruo Huang ◽  
Wenqi Du
Keyword(s):  
Seismic Hazard ◽  
Ground Motion ◽  
Ground Surface ◽  
Strong Motion ◽  
Response Spectra ◽  
Dynamic Responses ◽  
Motion Time ◽  
Acceleration Time Histories ◽  
Time Histories ◽  
Deterministic Seismic Hazard

Abstract. In performance-based seismic design, ground-motion time histories are needed for analyzing dynamic responses of nonlinear structural systems. However, the number of strong-motion data at design level is often limited. In order to analyze seismic performance of structures, ground-motion time histories need to be either selected from recorded strong-motion database, or numerically simulated using stochastic approaches. In this paper, a detailed procedure to select proper acceleration time histories from the Next Generation Attenuation (NGA) database for several cities in Taiwan is presented. Target response spectra are initially determined based on a local ground motion prediction equation under representative deterministic seismic hazard analyses. Then several suites of ground motions are selected for these cities using the Design Ground Motion Library (DGML), a recently proposed interactive ground-motion selection tool. The selected time histories are representatives of the regional seismic hazard, and should be beneficial to earthquake studies when comprehensive seismic hazard assessments and site investigations are yet available. Note that this method is also applicable to site-specific motion selections with the target spectra near the ground surface considering the site effect.

scholarly journals Design and Evaluation of the Initial 50th Percentile Female Prototype Rear Impact Dummy, BioRID P50F – Indications for the Need of an Additional Dummy Size

2021 ◽  
Vol 9 ◽  
Author(s):  
Anna Carlsson ◽  
Johan Davidsson ◽  
Astrid Linder ◽  
Mats Y. Svensson
Keyword(s):  
Angular Displacement ◽  
Crash Test ◽  
Head Restraint ◽  
Response Data ◽  
Rear Impact ◽  
Protection Systems ◽  
Crash Test Dummy ◽  
Rear Impacts ◽  
Lumbar Spinal ◽  
Head Neck

The objective of this study was to present the design of a prototype rear impact crash test dummy, representing a 50th percentile female, and compare its performance to volunteer response data. The intention was to develop a first crude prototype as a first step toward a future biofidelic 50th percentile female rear impact dummy. The current rear impact crash test dummy, BioRID II, represents a 50th percentile male, which may limit the assessment and development of whiplash protection systems with regard to female occupants. Introduction of this new dummy size will facilitate evaluation of seat and head restraint (HR) responses in both the average sized female and male in rear impacts. A 50th percentile female rear impact prototype dummy, the BioRID P50F, was developed from modified body segments originating from the BioRID II. The mass and rough dimensions of the BioRID P50F is representative of a 50th percentile female. The prototype dummy was evaluated against low severity rear impact sled tests comprising six female volunteers closely resembling a 50th percentile female with regard to stature and mass. The head/neck response of the BioRID P50F prototype resembled the female volunteer response corridors. The stiffness of the thoracic and lumbar spinal joints remained the same as the average sized male BioRID II, and therefore likely stiffer than joints of an average female. Consequently, the peak rearward angular displacement of the head and T1, and the rearward displacement of the T1, were lesser for the BioRID P50F in comparison to the female volunteers. The biofidelity of the BioRID P50F prototype thus has some limitations. Based on a seat response comparison between the BioRID P50F and the BioRID II, it can be concluded that the male BioRID II is an insufficient representation of the average female in the assessment of the dynamic seat response and effectiveness of whiplash protection systems.

scholarly journals Near Fault Effect on the Response of Single Hinged Compliant Offshore Tower

2018 ◽  
Vol 203 ◽  
pp. 01015
Author(s):  
Syed Yusuf Javed
Keyword(s):  
Offshore Structures ◽  
Dynamic Responses ◽  
Simultaneous Action ◽  
Integration Scheme ◽  
Random Waves ◽  
Sea Waves ◽  
Offshore Structure ◽  
Wave Condition ◽  
Near Fault ◽  
Time Histories

The response of compliant offshore structure under simultaneous action of random waves and earthquake loading has been analyzed. Since earthquake forces play a significant role in affecting the response of these offshore structures, comparative studies have been carried out considering near fault and far fault seismic excitations in the presence of moderate random sea waves. The offshore tower is modeled as an inverted pendulum with a cylindrical shaft connected by an articulated joint at the base. Seismic forces are evaluated by dividing the tower shaft into finite elements with masses lumped at the nodes. The nonlinearities associated with the system owing to variable submergence, drag force, variable buoyancy along with the geometry are considered in the analysis. The nonlinear dynamic equation of motion is formulated considering Lagrangian approach, which is solved in time domain by the Newmark-beta integration scheme. The sea state conditions, more precisely the water particle kinematics are evaluated using Airy’s wave theory along with the stretching modifications, as suggested by Chakrabarti. To minimize the dynamic responses, emphasis has to be given to the variations in height and position of the buoyancy chamber in extreme wave condition. The results are expressed in the form of time histories of deck displacement, hinge rotation, hinge shear and the bending moment. Parameters like maximum, minimum, mean and standard deviation are also determined by statistical analysis of response time histories of the dynamic responses at articulated joint.

Evaluation of Rear Impact Seat System Performance Using a Combined Load Neck Injury Criteria and Hybrid III Surrogates

2001 ◽  
Author(s):  
Kenneth J. Saczalski ◽  
Joseph Lawson Burton ◽  
Paul R. Lewis ◽  
Todd K. Saczalski ◽  
Peter E. Baray
Keyword(s):  
System Performance ◽  
Dynamic Tests ◽  
Actual Case ◽  
Combined Load ◽  
Occupant Protection ◽  
Rear Impact ◽  
Injury Criteria ◽  
Vehicle To Vehicle ◽  
Hybrid Iii

Abstract Vehicle to vehicle rear impact crash tests and sled buck tests were run to evaluate seat system performance related to Hybrid III surrogate response and comparison with NHTSA proposed combined load injury assessment values, as well as standard injury criteria. The crash and sled buck test impact conditions were modeled after actual case study incidents where changes in the rear impacted vehicle speeds ranged from about 25 to 50 kph. With the exception of one baseline vehicle-to-vehicle rear impact test, the dynamic tests provided side-by-side comparisons, and test-to-test evaluations, of surrogate response in conventional yielding front seats versus much stronger seat systems such as the belt integrated seat designs. Head, neck and chest injury criteria were used in the evaluations, including both the proposed NHTSA combined load neck criteria and SAE J 885 injury values. The surrogate response injury levels for the conventional yielding seats correlated well with the actual case study injury results. The seat comparison response generally indicated much reduced head and neck injury potential to surrogates seated in the stronger seat designs. The dynamic tests also demonstrate the importance of testing within the full vehicle interior structure to insure that floor strength is compatible with seat strength, so as to attain optimum occupant protection in stronger seat designs, and to assess injury risk to occupants in yielding or collapsing seat designs, as well as rear seated occupants, such as children. The tests indicate that quasi-static seat strength measurements made with more realistic “torso body block” load devices can provide reasonable estimates on the ultimate failure modes and dynamic load capabilities of the seat systems if the seat systems are properly mounted to the vehicle. Quasi-static seat strength results are presented for a variety of conventional collapsing seat designs and stronger seat systems like the belt integrated designs. One sled buck test was run with a rear-seated child surrogate to demonstrate the hazard of front seat collapse into the rear seat occupant area. The results of these tests further demonstrate the need for dynamic testing to assess total seat system performance and full occupant protection in rear impacts.

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