Lateral Impact Research Articles

Lateral Crushing and Energy Absorption Behavior of Multicellular Tube Structures

Thin-walled metallic tubular elements are extensively employed as an impact energy attenuator in modern vehicles owing to light weight, easy fabrication and average cost. Besides, the novel multi-cell tubular structures have superior energy absorption characteristics related to a conventional simple cell tube. In this research article, the finite element simulation of thin-walled aluminium alloy extruded multicellular structure under lateral impact loading is investigated. Nonlinear impact simulations were performed on multicellular tubes of various configurations using finite element ABAQUS/CAE explicit code. From the outcomes attained, the energy absorption capability of various multicellular tube structures were compared and it shows that multicellular tubes have more remarkable than that of traditional simple cell tubes. Moreover, square shaped multicellular structure tube were retained as most prominent for higher energy absorption. This type of multicellular tubes was found to be effective one to improve the lateral crashworthiness performance.

The derailment behaviour and mechanism of a subway train under frontal oblique collisions

Frontal oblique collision is more likely to cause train derailment and result in more serious consequences. In order to investigate the effect of impact angle on the derailment behaviour and mechanism of a subway train under frontal oblique collisions, a finite element model of train-rigid wall is established based on a four-section train running at 25 km/h. The oblique impact angle ranges from 6.34° to 45°. Numerical results indicate that middle coupler movements and lateral impact force are two main factors influencing derailment behaviours of the train during oblique collisions. For this reason, at 6.34°, the train has no risk of derailment. As the impact angle increases to 11.31°, train derails in saw-tooth mode and rear bogie of vehicle 1 derails. In oblique collisions of 15° and 20°, little-zigzag mode occurs with vehicle 1 and front bogie of vehicle 2 completely dropping from rail. However, once impact angle exceeds 25°, different movements of middle couplers have little influence on train derailment behaviours because impact force plays a leading role. In this condition, only vehicle 1 derails and the rest vehicles are not affected. Train derails in large displacement lateral mode. As to the analysis above, limiting yawing movement of middle couplers and improving lateral crashworthiness of vehicle structures are effective measures to decrease the risk of train derailment during oblique collisions.

The Impact of Brain Lateralization and Anxiety-Like Behaviour in an Extensive Operant Conditioning Task in Zebrafish (Danio rerio)

Several studies in mammals, birds, and fish have documented better cognitive abilities associated with an asymmetrical distribution of cognitive functions in the two halves of the brain, also known as ‘functional brain lateralization’. However, the role of brain lateralization in learning abilities is still unclear. In addition, although recent studies suggest a link between some personality traits and accuracy in cognitive tasks, the relation between anxiety and learning skills in Skinner boxes needs to be clarified. In the present study, we tested the impact of brain lateralization and anxiety-like behaviour in the performance of an extensive operant conditioning task. Zebrafish tested in a Skinner box underwent 500 trials in a colour discrimination task (red vs. yellow and green vs. blue). To assess the degree of lateralization, fish were observed in a detour test in the presence of a dummy predator, and anxiety-like behaviour was studied by observing scototaxis response in an experimental tank divided into light and dark compartments. Although the low performance in the colour discrimination task did not permit the drawing of firm conclusions, no correlation was found between the accuracy in the colour discrimination task and the behaviour in the detour and scototaxis tests. This suggests that neither different degrees of asymmetries in brain lateralization nor anxiety may significantly impact the learning skills of zebrafish.

Experimental and numerical study on impact resistance of RC bridge piers under lateral impact loading

Vehicle collisions with piers are main threat to bridge structures, thus the impact resistance of pier is significant for bridge structure safety. This paper presents the experimental and numerical work undertaken for investigating the impact process, damage and failure mode, dynamic behavior, and impact resistance evaluation method of reinforced concrete (RC) piers under lateral impact loading. By using a horizontal impact system, a series of simplified truck model collision test on the square sectional RC piers are performed, in which two main designing parameters, i.e., impact velocity and longitudinal reinforcement ratio, are especially concerned. Moreover, the detailed finite element models are established by the commercial program LS-DYNA, which are verified against the test results. It indicates that, the shape of impact force time-history does not exhibit the platform stage compared with that of the conventional drop hammer impact tests attributed to the shear failure mode occurred for the present columns; the damage level, impact force, displacement at impact position and energy dissipation rise with increasing the impact velocity; increasing the longitudinal reinforcement ratio improves the impact resistance of RC piers effectively; a plastic hinge forms with the hoop reinforcement yielding before the shear failure of column; the impact force causes a considerable change of the axial force of RC piers during the impact process. Finally, based on the energy conservation law, the residual displacement at the impact position is adopted and validated as the reasonable criterion for evaluating the impact resistance of RC piers. The present work can provide helpful references for the anti-collision design and impact resistance evaluation of the urban and highway bridge piers.

EFFECT OF MATERIAL MODEL SELECTION ON LATERAL IMPACT SIMULATIONS OF PELVIC COMPLEX

Material mechanical behavior plays an important role in pelvic complex simulation under lateral impact. Aiming to investigate effects of material model selection on the responses of lateral impact simulations, a seating pelvic complex model was constructed. The model was subjected to a series of impacts at velocity of 3–10[Formula: see text]m/s, and two material models were, respectively, assigned to the pelvic bone to evaluate the accuracy of the simulation. The results showed that the pelvic response and fracture pattern with plastic–elastic material model agreed well with the literature, while linear elastic material model was dissatisfied factory, especially the pelvic response at low velocity deviated from most cadaveric test data. In addition, drastic change of arterial pressure was responsible for hemorrhages associated with pelvic fracture. Ligament loading sequence verified that the posterior pelvic ring bore the greatest amount of load during the impact. Based on the above findings, we concluded that a plastic–elastic with strain rate effect material model can improve the simulation accuracy of pelvic complex under lateral impact, and pelvic fracture pattern may help to estimate the parameters’ selection in impact simulation.

Compression-based injury variables from chestbands in far-side impact THOR sled tests

Objective: This study seeks to determine compression (Cmax) and compression-related injury variables (velocity and viscous injury criterion: Vmax and VCmax) from chestband data in pure lateral and oblique far-side impact sled tests.Methods: The 3-point belt–restrained mid-sized male Test Device for Human Occupant Restraint (THOR) dummy was placed on a buck and subjected to side impacts with and without center-mounted airbags. The change in velocity was 8.3 m/s for all conditions. Two chestbands were routed around the outer circumference of the THOR at the levels of the third and sixth ribs. Maximum chest deflections were computed using strain gauge signals from the chestbands and their temporal contours. Three methods were used to determine deflection metrics. The first method paralleled methods used in previously published human cadaver studies; the second method used the actual anchor point location and actual alignment of the dummy’s internal sensors; and the third method used the anchor location of the internal sensor but determined the sensor’s locations on the contour confining to the aspect of the sensor. These 3 approaches are abbreviated as the SD, ID, and TD variables. The injury variables Cmax, Vmax, and VCmax were determined according to accepted procedures. Their peak magnitudes were extracted and an evaluation of their accuracy was made based on the SD method.Results: The average SD-based Cmax magnitudes for the upper and lower chest levels were 0.12 and 0.17 m/s, the Vmax magnitudes were 5.3 and 1.8 m/s, and the VCmax magnitudes were 0.24 and 0.15 m/s, respectively. Other data are given for all variables at the 2 levels of the thorax in the body of this paper. The ID-based peak variables were the lowest, and this observation was true regardless of the aspect, right or left side. In contrast, the SD method produced the greatest magnitudes of the variables. The VCmax variable had the greatest normalized difference among all 3 injury variables.Conclusions: Though the present study is limited in scope, the predetermined placement of the internal sensors in the THOR dummy underpredicted chest deflection-related injury variables, and the viscous criterion was the least reliable variable in these lateral and oblique far-side impact sled tests.

Ultimate Capacity of Guardrail Supporting Pile Subjected to Lateral Impact Load Using Centrifuge Model Test

Ultimate Capacity of Guardrail Supporting Pile Subjected to Lateral Impact Load Using Centrifuge Model Test

An experimental and numerical study of reinforced conventional concrete and ultra-high performance concrete columns under lateral impact loads

This paper presents an experimental and numerical study on the dynamic behaviour of axially-loaded reinforced conventional concrete (RC) and ultra-high performance concrete (UHPC) columns against low-velocity impact loading. The test specimens were divided into two groups with square and circular cross-section shapes, and each group includes both RC and UHPC columns. The impact scenario was modelled with a drop weight falling freely on the column mid-span. Brittle failure with shear plug formation was observed in RC columns while UHPC columns remained a flexure response with minimal damage under severe impact loads. To further interpret the experimental data, detailed finite element (FE) models were developed for RC and UHPC columns. A Continuous Surface Cap Model (CSCM) which accounts for the triaxial material strength, post peak softening and strain rate effect was adopted for UHPC material. After validating the material and structural model based on the testing data, extensive numerical simulations were performed to predict the UHPC column residual loading capacity after lateral impacts. Impact mass-velocity (M-V) diagrams were derived for the UHPC column damage assessment, and analytical formulae which could be easily applied to generate M-V diagrams were derived based on parametric studies.

ATD Biodynamics During Lateral Impact for USAF Neck Injury Criteria

Research was conducted involving a series of lateral impact tests on a horizontal sled facility by scientists at the Air Force Research Laboratory (AFRL). The purpose of the research was to conduct an assessment of the biodynamic response of an anthropomorphic test device (ATD) to support the development of AFRL neck injury criteria. Impacts were completed using a 50th male Hybrid III aerospace ATD due to this ATD being used by the USAF to qualify and evaluate ejection systems. A test matrix was developed to assess ATD response as a function of various seat configurations which were an approximation of the seat configurations used by the Medical College of Wisconsin (MCW) for previously conducted lateral impact tests of PMHS subjects (post-mortem human subjects). The specially fabricated seat configurations were a rigid seat fixture with a 5-point harness and a padded rigid seat with a 3-point harness. The input acceleration pulses were trapezoidal in shape and varied in peak magnitude from 8.5 to 17 G. The rigid and padded seat configurations both generated fairly linear ATD responses across the input acceleration range. The ATD’s response with the padded seat and the 3-point restraint was greater than the ATD’s response with the rigid seat and the 5-point restraint with the upper neck. The My torque showed the greatest increase from the rigid seat configuration to the padded seat configuration. This highlights the importance of a proper restraint and the importance of controlling the motion of the torso since it could reduce the loads and torques of the unrestrained head and neck, resulting in a lower probability of injury. The lateral impact program with the ATD provided critical impact data to fill data gaps that support the development of the ATD-to-human transfer functions for AFRL’s Multi-Axial Neck Injury Criteria (MANIC) for lateral impact or MANICy calculation. The program also highlighted gaps in human and PMHS head response data in identical lateral impact configurations that would not only improve the current MANICy transfer function but would allow the investigation of the efficacy of using the 6F-MANICy to replace the current MANICy.

Resistance mechanism and reliability analysis of reinforced concrete columns subjected to lateral impact

In the present study, reliability analysis is carried out to evaluate the structural safety of prototype reinforced concrete (RC) columns under lateral impact loading. Since RC columns are prone to suffer shear failure due to the large shear force forming in a short interval of time, the resistance mechanism in the local response stage is numerically investigated using finite element (FE) models verified against experimental results from the literature. Based on the simulation results, a novel methodology is proposed and validated to predict the inertial force distribution of RC columns at the peak impact force, and empirical formulas for predicting the impact actions in the local response stage are derived. Moreover, a simplified analytical model on the basis of the shear failure mechanism is proposed to determine the dynamic shear demand of the column. Incorporating the uncertainties associated with the structural and impact loading properties, shear failure probabilities of RC columns are evaluated with Monte Carlo simulation method to derive fragility curves dedicated to risk analysis. The limit state function is set up based on the dynamic shear capacity for the damage assessment. From the analysis results, it is found that the structural reliability of RC columns under impact loadings is sensitive to impact mass, impact velocity, section area and concrete strength. In addition, the proposed method is convenient to implement and could be a powerful tool for the anti-impact design of RC components.

Piles and lateral loads: comparison of calculation methods

Introduction. Calculation and analysis of pile resistance to loads remains to be a relevant problem in geoengineering. The design of pile foundations is currently performed using diverse analytical, empirical and numerical methods. However, the reliability of these methods remains to be a topic of interest among researchers and designers. This research paper analyses methods used for calculating the lateral-load capacity of piles in comparison with field-test data. Materials and methods. The paper dwells upon the development of reliable analytical expressions based on mathematical models of the pile–soil interaction. Main existing mathematical models of the soil environment, including the Mohr – Coulomb elastic ideal plastic model and the hardening soil model (HSM) were analysed. A particular attention was paid to a variety of factors affecting the pile–soil interaction, such as natural factors, pile types, pile sinking depth and technology, configurations of loads, as well as time-changed processes. A comparison of methods for calculating the lateral-load capacity of piles was conducted. To that end, calculations using the Mohr – Coulomb model and the local elastic strain theory (still required by building codes) were performed. High-level solid elements were used to develop and compute a finite-element pile-in-soil model in a spatial setting. Another model on the basis of parametric pile elements was designed using the MIDAS software. Results. It is established that the use of numerical calculation methods for evaluating the capacity and movements of pile foundations provides results comparable to those of field tests. These methods demonstrate a higher reliability compared to standardized analytical techniques. Conclusions. The reliability of numerical calculations of pile resistance to lateral impact is shown to be sufficiently high, thus being feasible for use in geoengineering. The use of these methods should be based on advanced non-linear soil models, such as HS, CamClay, etc.

Performances of magnesium- and steel-based 3D fiber-metal laminates under various loading conditions

The marriage of composites and metals is becoming an increasingly popular approach for obtaining resilient and lightweight materials. Our research group recently combined a 3D fiberglass/epoxy composite and thin magnesium sheets to render a significantly more effective and resilient light-weight material system. We are now interested in evaluating the feasibility of using steel as an alternative to magnesium due to the widespread use of steel in the automobile industry. Therefore, in this paper, the static buckling, impulse buckling, post-buckling, and lateral impact performances of the magnesium-based and steel-based 3D fiber-metal laminates (3D-FML) are systematically investigated and compared.

Multifunctional Arc-Welding Controller Using SOSMC Technique

With the help from all round technological growth, the control needs of many engineering processes are now better understood and better controlled. It has been noticed that during the prolonged concept development phase of sliding mode control (SMC), the control needs in arc-welding process, in particular, have drifted significantly. Now, single controller is capable of making all type of joint characteristics using different methods. Well-researched SMC concept has not been tried yet to develop multifunctional arc controller to cater multi input applications. Proportional-plus-integral controller, with assistance from modern soft-switched power converter topology, in particular, is strongly placed. In this brief, using super-twisting algorithm, the second-order SMC concept has been applied to design a complete multifunctional arc-welding controller. Apart from demonstrating superior control characteristics, this brief also elaborates the lateral impact of robustness measures. It also explores whether the proposed controller can deliver as a superior alternate for complete control of arc-welding process.

Bidirectional self-locked energy absorbing system: Design and quasi-static compression properties

Thin-walled tubes are widely utilized as energy absorption element. It is necessary to realize the bidirectional self-locked of thin-walled tube system without any constraint under lateral and oblique impact for emergency protection and improving energy absorption. In this study, we designed a novel 3D printed thin-walled tube with variable section achieving rapid assembly of bidirectional self-locked thin-walled system. Comparison among the thin-walled tube with variable section, dumbbell-shaped tube, rectangular-shaped tube and three corresponding systems were conducted with regard to deformation and energy absorption. The typical deformation modes of three kinds of tube and system were obtained by experimental results. Oblique quasi-static compression tests were conducted to validate the bidirectional self-locked effect of system. Geometrical restriction satisfying bidirectional self-locked effect and parametric analysis of presented tube is discussed. It was found that specific energy absorption of the presented thin-walled tube with variable section is superior to these of dumbbell-shaped configuration and rectangular-shaped configuration from both perspectives of tube and system.

Prediction of stress shielding around implant screws induced by three-point and four-point bending

Implant screws failure commonly occurs due to the load that constantly generated by the patient’s body to the fracture area. Bending load is often encountered in femur bone due to lateral impact which affected the bone and also the implants installed. Consequently, the load will lead to the failure of implants that can cause loosening or tightening of implants. Henceforth, in this manner, it is significant to study the bending behavior of bone implant in femur bone. The aim of this study was to analyze the stress shielding of bone implant on the internal fixator. 3D technique is able to show the overall deformation and stress distribution. The lower the biomechanical compatibility, the lower the STP value obtained. In addition, the variation of elastic modulus (E) of the screws materials, 200GPa (Stainless Steel) and 113.8GPa (Titanium) resulted in the increase of the total stress transferred (STP) between screw and bone interface. In this work, strain energy density (SED) was determined as a good indicator of stress shielding.

Lateral impact behavior of double-skin steel tubular (DST) members with ultra-high performance fiber-reinforced concrete (UHPFRC)

This study investigates the lateral impact behavior of double-skin steel tubular (DST) members with ultra-high performance fiber-reinforced concrete (UHPFRC). A total of six specimens were prepared and tested under lateral impact loading. In addition to UHPFRC filled DST members, normal strength concrete (NSC) filled DST member was also tested for comparison. Other investigated parameters in this study include the impact energy, the outer steel tube thickness, the inner steel tube thickness, and the presence of axial force. The test results demonstrate that the UHPFRC filled DST members exhibit significantly higher lateral impact resistance capacity than the NSC filled DST member. The impact energy and the outer steel tube thickness significantly affect the lateral impact behavior of UHPFRC filled DST members, while the influence of inner steel tube thickness is insignificant. With the applied axial force in this study, the influence of axial force is also insignificant. Afterwards, numerical model was developed and validated by the present test results. Based on the validated numerical model, the mid-span bending moment distributions and the stress wave propagations were investigated. Finally, parametric analyses were carried out to investigate the influences of different parameters on the lateral impact behavior of UHPFRC filled DST members.

Study on the impact behaviour of concrete-encased CFST box members

This paper presents an experimental and numerical study on the lateral impact behaviour of concrete-encased concrete-filled steel tubular (CFST) box beams and columns. A total of 20 specimens with test parameters including the impact energy, the boundary conditions and the axial load level, are tested under a drop hammer impact apparatus. The experimental results, namely the failure modes, the time-history of the impact force and mid-span deflection, as well as the whole impact process, are analysed. It shows that the specimens fail in a shear-flexural pattern under the impact. The major features of the impact force and mid-span deflection curves are summarised and analysed. The influence of test parameters on the impact behaviour of the specimens, namely the peak value of the impact force, the impact duration and the residual mid-span deflection, are also discussed. A finite element analysis (FEA) model is established to investigate the composite effects between the RC and CFST components. The analysis shows that the RC component is the major impact resistance component in the structure. The CFST components, on the other hand, is well protected by the RC component and do not experience severe damage. The composite effects make the structure safer under impact loading and easier to be restored after impact.

Crashworthiness analysis and bionic design of multi-cell tubes under axial and oblique impact loads

Creatures in nature adapt to the environment by a long-term evolution, they often obtain the optimization structures for hunting and self-defence. One such example is a marine crustaceans named Odontodactylus scyllarus (O. scyllarus) has hammer-like dactyl clubs, which can bear high-velocity impacts and absorb the impact energy efficiently. In this paper, a novel bionic multi-cell tube (BMT) with three layers of circular columns was designed, inspired by dactyl clubs structure of O. scyllarus. The crashworthiness of BMTs with different bionic-cell numbers were investigated under axial and oblique loads using nonlinear finite element (FE) method through LS-DYNA. Secondly, a complex proportional assessment (COPRAS) method was used to select the best possible sectional configuration under multiple loading angles. According to this method, the BMT with five cells (BMT-5) was determined to be the best design based on multicriteria process. Finally, a metamodel-based multiobjective optimization method based on polynomial regression (PR) metamodel and multiobjective particle optimization (MOPSO) algorithm were employed to optimize the dimensions of the BMT-5, where Fmax and EA were taken as objectives and wall thickness t and middle circle diameter D2 regarded as the design variables. The multiobjective optimization results showed that the BMT-5 has variant optimal solutions under different single loading angles. The optimal solutions of mulitobjective optimization under the multiple loading angles was highly dependent on the selection of weighting factors for different loading cases. Further research is required to investigate the crashworthiness analysis of BMTs under lateral impact.

Study of Hydraulic Steering Process for Articulated Heavy Vehicles Based on the Principle of the Least Resistance

This paper presents a new model for the hydraulic steering mode of articulated heavy vehicles (AHVs). The objective is to obtain the more accurate vehicle performance during steering process. The dynamic analyses of the hydraulic steering system, and the kinematic analyses of steering mechanical structure, including the steering wheel, articulation joint, and struts provide the constraints for the study of steering process with the principle of the least resistance. Meanwhile, a three-DOF dynamic model is developed to analyze the force characteristics of vehicle components. In order to verify the model, field tests and the comparisons with existing research works are performed. The results show that the present model is more effective and similar with the real steering process of AHVs. Moreover, another three conclusions can also be drawn: 1) Only 20% of the hydraulic pressure provides steering driving force. The rest is wasted, which is used to overcome the resistance of outlet pressure in hydraulic system itself. 2) The lateral resistance of each wheel is much greater than the longitudinal, but for the energy consumptions of lateral direction only accounting for 0.1% of longitudinal. Therefore, the lateral forces cannot be ignored in the dynamic model. But for the control strategy with minimum energy consumption, it is useless to consider the energy of lateral impact. 3) Road conditions or vehicle parameters such as the load, the wheel tread, or the wheel base, influence wheel resistances easily, which further influence the vehicle steering process. Furthermore, the vehicle trajectory and differential forces of each wheel obtained from the model are credible to be the reference of intelligent control for AHVs.

Validated thoracic vertebrae and costovertebral joints increase biofidelity of a human body model in hub impacts

Objective: A recent emphasis on nontraditional seating and omnidirectional impact directions has motivated the need for deformable representation of the thoracic spine (T-spine) in human body models. The goal of this study was to develop and validate a deformable T-spine for the Global Human Body Models Consortium (GHBMC) M50-O (average male occupant) human model and to demonstrate improved biofidelity.Methods: Eleven functional spinal units (FSUs) were developed with deformable vertebrae (cortical and trabecular), spinal and costovertebral ligaments, and intervertebral discs. Material properties for all parts were obtained from the literature.FSUs were subjected to quasistatic loads per Panjabi et al. (1976) in 6 degrees of freedom. Stiffness values were calculated for each moment (Nm/°) and translational force (N/µm). Updated costovertebral (CV) joints of ribs 2, 6, and 10 were subjected to moments along 3 axes per Duprey et al. (2010). The response was optimized by maximum force and laxity in the ligaments. In both cases, updated models were compared to the baseline approach, which employed rigid bodies and joint-like behavior. The deformable T-spine and CV joints were integrated into the full M50-O model Ver. 5.0β and 2 full-body cases were run: (1) a rear pendulum impact per Forman et al. (2015) at speeds up to 5.5 m/s. and (2) a lateral shoulder impact per Koh (2005) at 4.5 m/s. Quantitative evaluation protocols were used to evaluate the time history response vs. experimental data, with an average correlation and analysis (CORA) score of 0.76.Results: All FSU responses showed reduced stiffness vs. baseline. Tension, extension, torsion, and lateral bending became more compliant than experimental data. Like the experimental results, no trend was observed for joint response by level. CV joints showed good biofidelity. The response at ribs 2, 6, and 10 generally followed the experimental data.Conclusions: Deformable T-spine and CV joint validation has not been previously published and yielded high biofidelity in rear impact and notable improvement in lateral impact at the full body level. Future work will focus on localized T-spine injury criteria made possible by the introduction of this fully deformable representation of the anatomy.