Measured Impact Force Research Articles

How accurately do finite element models predict the fall impact response of ex vivo specimens augmented by prophylactic intramedullary nailing?

Hip fracture prevention approaches like prophylactic augmentation devices have been proposed to strengthen the femur and prevent hip fracture in a fall scenario. The aim of this study was to validate the finite element model (FEM) of specimens augmented by prophylactic intramedullary nailing in a simulated sideways fall impact against ex vivo experimental data. A dynamic inertia-driven sideways fall simulator was used to test six cadaveric specimens (3 females, 3 males, age 63-83 years) prophylactically implanted with an intramedullary nailing system used to augment the femur. Impact force measurements, pelvic deformation, effective pelvic stiffness, and fracture outcomes were compared between the ex vivo experiments and the FEMs. The FEMs over-predicted the effective pelvic stiffness for most specimens and showed variability in terms of under- and over-predicting peak impact force and pelvis compression depending on the specimen. A significant correlation was found for time to peak impact force when comparing ex vivo and FEM data. No femoral fractures were found in the ex vivo experiments, but two specimens sustained pelvic fractures. These two pelvis fractures were correctly identified by the FEMs, but the FEMs made three additional false-positive fracture identifications. These validation results highlight current limitations of these sideways fall impact models specific to the inclusion of an orthopaedic implant. These FEMs present a conservative strategy for fracture prediction in future applications. Further evaluation of the modelling approaches used for the bone-implant interface is recommended for modelling augmented specimens, alongside the importance of maintaining well-controlled experimental conditions.

DropletMask: Leveraging visual data for droplet impact analysis

AbstractMachine learning‐assisted computer vision represents a state‐of‐the‐art technique for extracting meaningful features from visual data autonomously. This approach facilitates the quantitative analysis of images, enabling object detection and tracking. In this study, we utilize advanced computer vision to precisely identify droplet motions and quantify their impact forces with spatiotemporal resolution at the picoliter or millisecond scale. Droplets, captured by a high‐speed camera, are denoised through neuromorphic image processing. These processed images are employed to train convolutional neural networks, allowing the creation of segmented masks and bounding boxes around moving droplets. The trained networks further digitize time‐varying multi‐dimensional droplet features, such as droplet diameters, spreading and sliding motions, and corresponding impact forces. Our innovative method offers accurate measurement of small impact forces with a resolution of approximately 10 pico‐newtons for droplets in the micrometer range across various configurations with the time resolution at hundreds of microseconds.

The Influence of Effective Mass on the Striking Force of Lead Jab and Rear Cross Punches of Boxers

Background: Modern combat sports, including boxing, categorize participants by body mass to ensure fairness and safety. The effective mass, or the ability to maximize body mass during a punch, significantly impacts striking force. This study aims to explore the relationship between effective mass and striking force in lead jab and rear cross punches of boxers. Material and methods: Thirteen male boxers with an average body mass of 90.6 kg and average height of 184 cm participated. The study employed an AMTI MC12-2K force plate (AMTI, Watertown, MA, USA) and Noraxon Ultium EMG sensors (Noraxon, Scottsdale, AZ, USA) to measure impact force and acceleration. Each boxer performed five maximum-force strikes with both lead jab and rear cross techniques. Results: The rear cross punch generated significantly higher ground reaction force (1709.28 ± 486.62 N) compared to the lead jab (1182.56 ± 250.81 N). However, effective mass values were similar for both punches: lead jab (18.95 ± 5.29 kg, 21.51% of body mass) and rear cross (18.50 ± 5.56 kg, 21.04% of body mass). Higher body mass and longer training tenure positively correlated with higher effective mass. An inverse relationship was found between fist acceleration and effective mass. Conclusions: Effective mass plays a crucial role in punch biomechanics, with similar utilization between lead jab and rear cross punches despite the latter’s higher force. Training focused on optimizing body mass utilization and refining punch techniques can enhance punch effectiveness.

Impact force measurement by in-plane piezoelectricity of polyvinylidene fluoride films

This manuscript provides a new idea to solve the problems related to measurement of impact force wave especially in the situation with a strong environment noise by utilizing the polyvinylidene fluoride (PVDF) film instead of strain gauge. According to our experimental results, an extremely high ratio between output signal and noise in environment (SN ratio) is realized even the infrequently employed in-plane piezoelectricity of film is utilized. Instead of piezoelectricity in thickness direction, attachment of film on Hopkinson pressure bar based on in-plane piezoelectricity could help us to avoid the influence from separation of Hopkinson pressure bar on measurement result. We could conclude that a more precise measurement could be realized by a short film rather than long one even though the short film shows a relative lower output signal. However, the output signal could be amplified by increasing its width. Besides, comparing with the use of strain gauge, broader bandwidth of film measurement is discovered. In the situation where the duration of impact force wave is extremely short, high accuracy measurement should be realized by PVDF film rather than strain gauge.

Finite elements analysis of drop weight impact loading on GLARE-6A

Fibre Metal Laminate (FML) is a damage-tolerant material being opted in modern aerospace industries. FML impact absorbing properties were studied for determining FML response against impact loading. The author contributed by experimentation of drop weight impacts on FML GLARE 6A samples. In this paper, the author reproduced drop weight impact simulation using Finite Element Analysis (FEA). The author modeled GLARE FML, and a simulation of drop weight impact was performed using the explicit dynamics module of ANSYS. The drop weight impact method in Ansys was used to analyse the impact force effect on GLARE FML. Simulation results depicted drop weight impacts measured impact force, velocity, and energy vs time. Maximum deformation of plots was presented.

Advancements in Bicycle Safety: Integrating Control Sensors and Artificial Intelligence for Enhanced Airbag Innovation

Abstract: Motorcycle safety is a critical concern in traffic systems worldwide. This paper introduces a novel approach to enhancing rider safety through the integration of airless tires and advanced airbag systems, underpinned by artificial intelligence (AI) and control sensors. Airless tires contribute to vehicle stability by eliminating the risk of sudden deflation, while AI-driven airbag systems promise dynamic protection for riders during collisions. The study begins with an analysis of airless tire technology, emphasizing its impact on motorcycle stability and safety. It then transitions to the development of motorcyclespecific airbag systems, which utilize AI to process sensor data and make real-time decisions regarding airbag deployment. The effectiveness of these systems is validated through crash simulation tests and impact force measurements, demonstrating a substantial reduction in injury severity. Challenges such as cost, user acceptance, and technical constraints are thoroughly examined. The paper concludes with a discussion on future trends, including the potential for AI to predict and prevent accidents before they occur, thereby setting a new standard for motorcycle safety.

Hopkinson bar impact force measurement for application to development of an artificial bird

A test method has been published for measuring forces from bird cadavers and artificial birds to demonstrate equivalency to support the use of artificial birds in aircraft certification testing. The test method involves a large diameter Hopkinson bar as the technique for measuring and comparing forces. The method involves the assumption that a force on one end of the bar results in a one-dimensional plane wave that travels down the bar. To avoid reflected waves from the end of the bar overlapping the input pulse, and due to practical limitations on the length of the bar, strain transducers are located relatively close to the impacted face of the bar, raising questions about the validity of the assumption of one-dimensional wave propagation. In addition, the large diameter of the bar can introduce dispersion effects in the propagated pulse. These must be assessed to determine the impact on the accuracy of impact force measurements and, if significant, dispersion correction techniques must be used. In this study analytical, experimental, and computational methods are used to analyze the wave propagation characteristics for impact forces expected from realistic bird impacts. While wave dispersion and effects of non-concentric impacts are present, the resulting errors are small relative to typical test-to-test variation observed in bird impact testing. For the response we expect to see in bird impacts up to velocities of approximately 300 m/s the large diameter Hopkinson bar test appears to be an acceptable method for measuring the impact forces and comparing the response of real and proposed artificial birds.

Optimization of Composite Cavitation Nozzle Parameters Based on the Response Surface Methodology

Cavitation is typically observed when high-pressure submerged water jets are used. A composite nozzle, based on an organ pipe, can increase shear stress on the incoming flow, significantly enhancing cavitation performance by stacking Helmholtz cavities in series. In the present work, the flow field of the composite nozzle was numerically simulated using Large Eddy Simulation and was paired with the response surface method for global optimizing the crucial parameters of the composite nozzle to examine their effect on cavitation behavior. Utilizing peak gas-phase volume percent as the dependent variable and the runner diameter, Helmholtz chamber diameter, and Helmholtz chamber length as independent variables, a mathematical model was constructed to determine the ideal parameters of the composite nozzle through response surface methodology. The optimized nozzle prediction had an error of only 2.04% compared to the simulation results, confirming the accuracy of the model. To learn more about the cavitation cloud properties, an experimental setup for high-pressure cavitation jets was also constructed. Impact force measurements and high-speed photography tests were among the experiments conducted. The simulated evolution period of cavitation cloud characteristics is highly consistent with the experimental period. In the impact force measurement experiment, the simulated impact force oscillates between 256 and 297 N, and the measured impact force oscillates between 260 N and 289 N, with an error between 1.5% and 2.7%. The simulation model was verified by experimental results. This study provides new insights for the development of cavitation jet nozzle design theory.

Impact Force and Velocities for Kicking Strikes in Combat Sports: A Literature Review.

Kicking strikes are fundamental in combat sports such as Taekwondo, karate, kickboxing, Muay Thai, and mixed martial arts. This review aimed to explore the measurement methods, kinematics such as velocities, kinetics such as impact force, determinants, and injury potential of kicking strikes in combat sports. Searches of Academic Search Premier, The Allied and Complementary Medicine Database, CINAHL Plus, MEDLINE, SPORTDiscus, Scopus, and Web of Science databases were conducted for studies that measured kicking velocity and impact force. A total of 88 studies were included in the review. Studies most frequently involved only male participants (49%) aged between 18 and 30 years of age (68%). Studies measuring velocity predominantly implemented camera-based motion capture systems (96%), whereas studies measuring impact force displayed considerable heterogeneity in their measurement methods. Five primary strikes were identified for which foot velocities ranged from 5.2 to 18.3 m/s and mean impact force ranged from 122.6 to 9015 N. Among the techniques analysed, the roundhouse kick exhibited the highest kicking velocity at 18.3 m/s, whilst the side kick produced the highest impact force at 9015 N. Diverse investigation methodologies contributed to a wide value range for kicking velocities and impact forces being reported, making direct comparisons difficult. Kicking strikes can be categorised into throw-style or push-style kicks, which modulate impact through different mechanisms. Kicking velocity and impact force are determined by several factors, including technical proficiency, lower body strength and flexibility, effective mass, and target factors. The impact force generated by kicking strikes is sufficient to cause injury, including fracture. Protective equipment can partially attenuate these forces, although more research is required in this area. Athletes and coaches are advised to carefully consider the properties and potential limitations of measurement devices used to assess impact force.

Impact load measurement of small multi-bubble explosions near solid wall

The interaction of multiple spark-generated bubbles near solid boundary is investigated experimentally. Qualitative study is done with high-speed imaging for bubble shape evolution and PVDF sensor for impact force measurement. Similar-sized bubbles are created synchronously and distance between bubbles or boundary is chosen to be as small as possible. The jet direction of two horizontally aligned bubbles is strongly influenced by proximity parameter (γ) near boundary. The role of inter bubble distance (η) between bubbles and its contribution to intensity of impulsive force is also presented. It is found that strongest impact is recorded for horizontal pair, compared to vertical pair and diagonal pair, for small η values. Three bubbles are arranged with middle one which is smaller, similar or bigger than left and right bubbles. Allocating bigger bubble in the center indeed produces the most destructive impact on boundary among all cases. Moreover, diverse bubble deformation features are witnessed for various combination of dimensionless parameter applied in this study.

Influence of trapping efficiency on the pile-up geometry of granular flows behind slit dams

The post spacing of slit dams is a key parameter that controls the trapping efficiency of these open-type countermeasures. In this study we conduct flume experiments of quasi-monodisperse spherical particles passing through slits to investigate the relationship between the trapping efficiency and the pile-up geometry, as well as the impact of the latter on the interaction between granular flows and slit dams. The ratio of the slit width relative to the particle size b/d is varied while the flume inclination is held constant. Tests reveal that at a critical ratio b/d∼2.3 trapping is most unstable. The trapping efficiency influences the geometry of the granular pile-up that deposits behind the dam after it has been jammed. When >52% of the granular mass is trapped (occurring at b/d≤2.3), the height of the final deposit changes with the trapping efficiency, whereas below this threshold value (when b/d≥3.1)the flow-wise length becomes more sensitive to the trapping. Impact force measurements further shed light on the mechanisms relating the trapping efficiency and the geometry and their effect on the total force fluctuations.

Benchtop impaction device replicates cadaveric loading conditions of the transforaminal lumbar interbody fusion (TLIF) procedure

Background contextLumbar spine disc pathologies often necessitate removal of the intervertebral disc and implantation of a lumbar interbody fusion (LIF) device. Herein, the objective was to measure use condition forces while simulating intra-operative loading conditions of transforaminal lumbar interbody fusion (TLIF) procedures. MethodsIn this work, we developed a transferable method to measure impact forces in a cadaveric intra-operative setting and designed a drop weight benchtop device equipped with force and displacement sensors to replicate cadaveric impact conditions, including number of strikes required for interbody device insertion, peak force, initial slope of the impact waveform, impact duration, and area under the force-time curve (impulse). Following cadaveric testing, a benchtop biomechanical study varying interbody device height, drop height, and drop weight was performed to evaluate the utility of the benchtop device to replicate impact loading conditions which occurred in the cadaveric model. ResultsSeveral benchtop test groups replicated the cadaver group in number of strikes required for device insertion. The average cadaveric peak force, 13.03 kN, was replicated by three benchtop groups: 12 mm device height, 60 cm drop height, 0.75 lb drop weight; 12 mm device height, 60 cm drop height, 1.0 lb drop weight; and 14 mm device height, 60 cm drop height, 0.50 lb drop weight. The initial slope of the impact waveform was replicated best by 12 mm devices. Both the impact duration and impulse were lower in all benchtop groups than in cadaver testing. ConclusionsThis work validated the outfitting of an impact force sensor onto an interbody device insertion instrument as a reproducible, quantifiable method for collecting impact loading data in a cadaveric model. This benchtop device and methodology will aid in testing interbody devices relative to anticipated use conditions, enhance interbody device designs, and accelerate surgical technique refinement.

Estimation of Nondestructive Compressive Strength of Concrete Using Impact Force Response Signal

Abstract This study examined the potential of the impact force response signal induced by impacting an object to estimate the compressive strength of concrete nondestructively. For this study, an automatic impacting device was devised, a system was set up to measure impact force signal, and a program was developed to analyze the obtained signal and estimate the compressive strength. Concrete test specimens were manufactured and tested. Impacts were carried out on the specimens, and the impact force signals were obtained. The signals were analyzed to obtain the total impact force signal energy, and a uniaxial compressive strength test was carried out on each specimen to measure the compressive strength directly. A good relationship was formed between the total impact force signal energy and the uniaxial compressive strength. The strength was estimated from the obtained relationship for new test specimens and compared with the directly measured strength. The comparison indicated that the estimated strength and the measured strength had a close relationship. In addition, a Schmidt hammer test was carried out on the new specimens before the uniaxial compressive test, and the test results were compared with those from the impact force signal energy. The strength estimation using the impact force signal energy had a better result. The study results show that the compressive strength of concrete materials could be estimated nondestructively using the proposed method.

Exploring the effect of building openings and orientation on induced loads due to extreme flood events

Understanding the impact of building features on flood-induced loads remains a major challenge. This study experimentally investigated the effect of building openings and orientation on horizontal forces and overturning moments by unsteady extreme floods. The physical model experiments for flood impacts were conducted concerning three intensity flood events (Hi), four porosities (P) resulting by opening, and seven orientations (γ) by building rotation. Measurement of impact forces and moments on the building model was carried out to explore the flood impacts on structures under unsteady flow conditions. By introducing a reduction coefficient of maximum horizontal force ηF, the influence of the porosity and orientation on flood loads was discussed. Results showed that either the building openings or the orientation exhibit a reduction effect on the resulting force and moment, and the magnitude of the reduction is negatively related to the flood intensity. For the permeable building with oriented exposures, the reduction coefficient ηF showed a W-shaped variation trend concerning γ at certain P, exhibiting a variable behavior of force reduction and increase with changes in P and γ. Finally, the load formulas, including maximum horizontal force and maximum overturning moment, were modified by quantifying the effects of openings and orientation, supporting hydraulic engineers for the load design of building structures.

Research on measurement methods and sensor selection of rocket gas jet impact force

Based on a rocket launcher gas jet impact force measurement method, this paper designed an experiment to study the influence of different types of sensors on the test results. By comparing and analysing the data waveforms and amplitudes measured by the three sensors at different distances, the accuracy of the test results of each sensor is obtained. The test results show that, for the gas jet impact force measurement method introduced in this paper, the choice of the DYLY-107 S-type strain gauge force sensor can more accurately monitor the impact flow field and impact force amplitude.

Elastodynamics of an overconstrained 8-SS platform for touchdown impact force measurement

Passive overconstrained parallel mechanism has many advantages due to extra constraints to the platform. When applied to the force sensor field, it can increase the capability, stiffness and dynamic response of the sensor. In this study, an overconstrained [Formula: see text] platform is presented to measure the multi-dimensional landing impact force. Screw theory is used to obtain the concentrated inertia force. Then, by adding the inertial force into the VJM (Virtual Joint Method) stiffness model, the static analysis is extended to elastodynamics analysis. Natural frequency and modal are derived from the elastodynamics equation and show well agreement with the FEA result in Abaqus. Theoretical force measurement equation is deduced. The FEA simulation result proves the effectiveness of the theoretical equation. Experiments are also conducted to verify the feasibility of the platform.

Multiple debris-resisting barriers with basal clearance: A study on impact force

Optimising debris-resisting barriers is of paramount importance on constructing cost-effective and eco-friendly mitigation works. Multiple barriers with basal clearance can potentially serve as an optimal approach because they can facilitate flow energy dissipation, reduce the impact force on each barrier, ease the maintenance and resist a large flow volume. However, the design impact force of multiple barriers with basal clearance remains empirical. In this study, physical model tests were carried out to investigate the impact force of idealised dry granular flow against dual rigid barriers with basal clearance using a 5-m-long flume model. Measured impact forces show that basal clearance attenuates the impact force exerted on the second barrier by apportioning the impact forces from basal discharge and overflow. Basal discharge dissipates the kinetic energy of landing flow and reduces the impact force of overflow. A rational design of basal clearance serves as an efficient measure for optimising the design of multiple barriers.

A tri-axial ice model for simulating ice-stiffened panel impact: Experiments and numerical modeling

The interaction of ice with a polar ship is complex, which may involve several ice failure mechanisms such as local crushing, tensile, cracking, bending, shearing, sliding and the ship structures could attain permanent deformations. A reasonable modeling of ice behavior is, therefore, critical to the analysis of ship-ice interactions. This paper reports an experimental and numerical study on the behavior of stiffened panels subject to the impact of a wedge-shaped ice block/indenter. The tested stiffened panel was mounted to a Falling Weight Impact Tester, and measurements were taken to help understand the dynamic responses of the structure and the ice, and also the permanent deformations. Finite element analyses using ABAQUS/EXPLICIT were also performed for the lab tests. The proposed ice model features a multi-surface yield function, empirical failure criteria for a few ice failure modes, and a representation of the remaining load carrying capacity of crushed ice. This ice model is implemented in a user-defined subroutine VUMAT and uses the cohesive element in a numerical solution. The predicted and measured impact force and structural deformation compared very well with the tests, indicating that the proposed ice model coded in VUMAT is reasonable. A series of parametric studies was then carried out to identify the key parameters of this new ice model that would have major effects on the prediction of ice impacts. The paper intends to provide test data that may be useful in understanding the complex ice-ship interaction and to introduce a numerical solution with a new ice model that improves the simulation of high-energy ice-ship impacts.

Methodology for Measuring the Impact Force of Compaction Rammers

In this paper a methodology to measure impact force is proposed. It includes conceptual description of the sequence of the steps, tools needed to carry out the measurement, validation and the post processing of the collected data and automated data acquisition during end-of-line testing. The proposed concept is also putting requirements to the needed equipment..

Shock absorber lateral and impact force measurement using a column-type sensor

A novel method for the lateral and impact force measurement of shock absorbers using a three-component column-type sensor is proposed in this study. The strain gauge configuration and the bridge connection were designed, and the outputs of each designed measuring bridge under both alignment and eccentric loading were theoretically analyzed. Simulations and experimental tests were conducted to validate the measuring bridge output of the theoretical analysis; the results from the theoretical analysis, simulation, and experiments agree well with one another. In accordance with the specifications put forth in the SAE J2570 standard, the designed sensor was calibrated to obtain its performance parameters and calibration coefficients, which were then applied to acquire the lateral and impact force of a shock absorber. The calibration results demonstrate that the maximum nonlinearity and hysteresis were 0.51% and 0.87% (full-scale), respectively, and the sensor had good linearity and weak coupling between dimensional characteristics.