scholarly journals An Evidence Basis for Future Equestrian Helmet Lateral Crush Certification Tests

2020 ◽  
Vol 10 (7) ◽  
pp. 2623 ◽  
Author(s):  
Thomas A. Connor ◽  
J. Michio Clark ◽  
Pieter Brama ◽  
Matt Stewart ◽  
Aisling Ní Annaidh ◽  
...  
Keyword(s):  
Time History ◽  
Test Method ◽  
Published Data ◽  
Mean Values ◽  
Safety Outcome ◽  
Certification Tests ◽  
Impact Location ◽  
Peak Loads ◽  
Equestrian Sports ◽  
Force Time

The aim of this study is to determine what loads are likely to be applied to the head in the event of a horse falling onto it and to determine by how much a typical equestrian helmet reduces these loads. An instrumented headform was designed and built to measure applied dynamic loads from a falling horse. Two differently weighted equine cadavers were then dropped repeatedly from a height of 1 m (theoretical impact velocity of 4.43 m/s) onto both the un-helmeted and helmeted instrumented headforms to collect primary force–time history data. The highest mean peak loads applied to the headform by the lighter horse were measured at the bony sacral impact location (15.57 kN ± 1.11 SD). The lowest mean peak loads were measured at the relatively fleshier right hind quarter (7.91 kN ± 1.84 SD). For the heavier horse, highest mean peak loads applied to the headform were measured at the same bony sacral impact location (16.02 kN ± 0.83 SD), whilst lowest mean peak loads were measured at the more compliant left hind quarter (10.47 kN ± 1.08 SD). When compared with the un-helmeted mean values, a reduction of 29.7% was recorded for the sacral impact location and a reduction of 43.3% for the lumbosacral junction location for helmeted tests. Notably, all measured loads were within or exceeded the range of published data for the fracture of the adult lateral skull bone. Current helmet certification tests are not biofidelic and inadequately represent the loading conditions of real-world “lateral crush” accidents sustained in equestrian sports. This work presents the first ever evidence basis upon which any future changes to a certification standards test method might be established, thereby ensuring that such a test would be both useful, biofidelic, and could ensure the desired safety outcome.

Determination of impact events on a plate-like composite structure

2016 ◽  
Vol 120 (1228) ◽  
pp. 984-1004 ◽  
Author(s):  
L. Xu ◽  
Y. Wang ◽  
Y. Cai ◽  
Z. Wu ◽  
W. Peng
Keyword(s):  
Composite Structures ◽  
Transfer Functions ◽  
Flat Glass ◽  
Time History ◽  
Identification Algorithm ◽  
Impact Location ◽  
Force Time ◽  
The Impact ◽  
The Relationship ◽  
Impact Events

ABSTRACTComposite materials have been increasingly used in aircraft structures. However, these composite structures are susceptible to damage from external low-velocity impacts. In this paper, an impact identification algorithm is proposed to estimate the impact location and force time history simultaneously. A localisation method based on basis vectors is proposed, and the impact force time history is reconstructed by simplified transfer functions. The basis vector stands for the relationship between the impact location and the sensor signals, and the transfer function shows the relationship of the sensor signal and the force time history. An experiment is conducted on a flat glass fibre-epoxy matrix composite plate to verify the developed algorithm using only four sensors. The soft impactor and hard impactor are two typical impactors for impact events; therefore, the impact experiment is performed by the rubber and the steel impactors, respectively. The experimental results indicate that the proposed algorithm is feasible for the identification of impact events on plate-like composite structures.

Brain Tissue Material and Damage Properties for Blast Trauma

2018 ◽  
Author(s):  
Soroush Assari ◽  
Kurosh Darvish
Keyword(s):  
Tissue Damage ◽  
Tissue Injury ◽  
Time History ◽  
Bovine Brain ◽  
Test Method ◽  
Material Behavior ◽  
Strain Rates ◽  
Path Dependent ◽  
Force Time ◽  
Blast Induced Neurotrauma

The aim of this study was to develop a test method to characterize the material behavior of bovine brain samples in large shear deformations and high strain rates relevant to blast-induced neurotrauma (BINT) and evaluate tissue damage. A novel shear test setup was designed and built capable of applying strain rates ranging from 300 to 1000 s−1. Based on the shear force time history and propagation of shear waves, it was found that the instantaneous shear modulus (about 6 kPa) was more than 3 times higher than the values previously reported in the literature. The shear wave velocity was found to be strain path dependent which is an indication of tissue damage at strains greater than 10%. The results of this study can help in improving finite element models of the brain for simulating tissue injury during BINT.

Physical Modelling of Hydrodynamic Loads on Piggyback Pipelines in Combined Wave and Current Conditions

2010 ◽  
Author(s):  
Masˇa Brankovic´ ◽  
Hammam Zeitoun ◽  
James Sutherland ◽  
Andrew Pearce ◽  
Vagner Jacobsen ◽  
...  
Keyword(s):  
Time History ◽  
Physical Modelling ◽  
Model Tests ◽  
Test Method ◽  
Hydrodynamic Loads ◽  
Time Histories ◽  
Flow Mechanisms ◽  
Force Time ◽  
The Stability ◽  
Pipeline Design

One of the aspects of pipeline design is ensuring pipeline stability on the seabed under the action of environmental loads. During the 1980s, significant efforts were made to improve the understanding of hydrodynamic loads on single pipeline configurations on the seabed (Reference 1). The stability of piggyback (bundled) pipeline configurations is less well understood, with little quantitative data readily available to the design engineer for practical application in engineering problems (References 2–6). This paper describes an extensive set of physical model tests performed for piggyback on-seabed and piggyback-raised-from seabed (spanning or lifting pipeline) configurations to determine hydrodynamic forces in combined wave and current conditions. The piggyback is nominally in the 12 o’clock position. The well-established carriage technique was used, in order to obtain data for use in full-scale stability modelling. The model tests are benchmarked against existing test data, to confirm the validity of the test method. Key findings are presented in terms of non-dimensional coefficients, and force time histories for the vertical and horizontal forces. A brief interpretation of the hydrodynamic load behaviour of the Piggyback System is provided by considering the physical flow mechanisms causing the force time history variation; furthermore the influence of the seabed separation on the piggyback loads is also discussed.

scholarly journals Hygrothermal Ageing Influence on BVI-Damaged Carbon/Epoxy Coupons under Compression Load

Polymers ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 2038
Author(s):  
Maria Pia Falaschetti ◽  
Matteo Scafé ◽  
Nicola Zavatta ◽  
Enrico Troiani
Keyword(s):  
Residual Strength ◽  
Impact Damage ◽  
Mechanical Analysis ◽  
Test Method ◽  
Combined Loading ◽  
Compression Load ◽  
Impact Location ◽  
Hygrothermal Ageing ◽  
Influence Of Water ◽  
Compressive Tests

Composite materials usage in several industrial fields is now widespread, and this leads to the necessity of overcoming issues that are still currently open. In the aeronautic industry, this is especially true for Barely Visible Impact Damage (BVID) and humidity uptake issues. BVID is the most insidious kind of impact damage, being rather common and not easily detectable. These, along with the ageing that a composite structure could face during its operative life, could be a cause of fatal failures. In this paper, the influence of water absorption on impacted specimens compressive residual strength was studied. Specimens were impacted using a modified Charpy pendulum. Two different locations were chosen for comparison: Near-Edge (NE) and Central (CI). Accelerated hygrothermal ageing was conducted on impacted and reference nonimpacted coupons, placing them in a water-filled jar at 70 °C. Compressive tests were performed in accordance with the Combined Loading Compression (CLC) test method. A Dynamic Mechanical Analysis (DMA) was performed as well. The results showed the influence of hygrothermal ageing, as expected. Nevertheless, the influence of impact location on compressive residual strength is not clearly noticeable in aged specimens, leading to the conclusion that hygrothermal ageing may have a greater effect on composite compressive strength than the analysed BVI damage.

An Energy-Based Method for Testing Cushioning Durability of Running Shoes

1993 ◽  
Vol 9 (1) ◽  
pp. 27-46 ◽  
Author(s):  
John F. Swigart ◽  
Arthur G. Erdman ◽  
Patrick J. Cain
Keyword(s):  
Maximum Energy ◽  
Test Method ◽  
New Method ◽  
Testing System ◽  
Materials Testing ◽  
Wear Factor ◽  
Time Profiles ◽  
Running Shoes ◽  
Computer Controlled ◽  
Force Time

A new method for quantifying shoe cushioning durability was developed. This method used a computer-controlled, closed-loop materials testing system to subject the shoes to force-time profiles that were indicative of running. The change in the magnitude of the maximum energy absorbed by a shoe and the change in the magnitude of the energy balance of the shoe were quantified after the shoe had been worn running for a given distance. A shoe that changed very little in these quantities had a small energy wear factor and was deemed to have durable cushioning. The test method was roughly validated through comparison of three shoes of different midsole constructions with known relative durabilities. The shoes were tested at four simulated running speeds for energy properties when they were new and after they were run in for 161 km. The relative durabilities of the tested shoes were consistent with expectations based on the shoes' materials and constructions, showing that the new method has promise in predicting shoe cushioning durability, and thus more complete studies of the method may prove useful.

scholarly journals Automatic measurement and characterization of the dynamic properties of tethered membrane wings

2019 ◽  
Vol 4 (1) ◽  
pp. 41-55 ◽  
Author(s):  
Jan Hummel ◽  
Dietmar Göhlich ◽  
Roland Schmehl
Keyword(s):  
Dynamic Properties ◽  
Test Procedure ◽  
Control Unit ◽  
Automatic Measurement ◽  
Simulation Models ◽  
Test Method ◽  
Subsequent Work ◽  
Aerodynamic Parameter ◽  
Mean Values

Abstract. We have developed a tow test setup for the reproducible measurement of the dynamic properties of different types of tethered membrane wings. The test procedure is based on repeatable automated maneuvers with the entire kite system under realistic conditions. By measuring line forces and line angles, we determine the aerodynamic coefficients and lift-to-drag ratio as functions of the length ratio between power and steering lines. This nondimensional parameter characterizes the angle of attack of the wing and is varied automatically by the control unit on the towed test bench. During each towing run, several test cycles are executed such that mean values can be determined and errors can be minimized. We can conclude from this study that an objective measurement of specific dynamic properties of highly flexible membrane wings is feasible. The presented tow test method is suitable for quantitatively assessing and comparing different wing designs. The method represents an essential milestone for the development and characterization of tethered membrane wings as well as for the validation and improvement of simulation models. On the basis of this work, more complex maneuvers and a full degree of automation can be implemented in subsequent work. It can also be used for aerodynamic parameter identification.

Damage Detection in Rods Using Wave Propagation and Regression Analysis

1999 ◽  
Author(s):  
K. T. Feroz ◽  
S. O. Oyadiji
Keyword(s):  
Wave Propagation ◽  
Regression Analysis ◽  
Damage Detection ◽  
Numerical Study ◽  
Time History ◽  
Ball Impact ◽  
Spherical Ball ◽  
Time Histories ◽  
Measured Strain ◽  
Force Time

Abstract The phenomena of wave propagation in rods was studied both numerically and experimentally. The finite element (FE) code ABAQUS was used for the numerical study while PZT (lead zirconium titanate) sensors and a 50 MHz transient recorder were used experimentally to monitor and to capture the propagation of stress pulses. For the study of damage detection in the rods the analyses and the experiments were repeated by introducing slots in a fixed axial location of the rod. A longitudinal wave was induced in the rod via collinear impact which was modelled in the FE analyses using the force-time history computed from the classical Hertz contact theory. In the experimental measurements this was achieved by a spherical ball impact at one plane end of the rods. It is shown that the predicted and measured strain-time histories for the defect-free rod and for the rods with defect correlate quite well. These results also show that defects can be located using the wave propagation phenomena. A regression analysis technique of the predicted and measured strain histories of the defect free rod and of the rod with defect was also performed. The results show that this technique is more efficient for smaller defects. In particular, it is shown that the area enclosed by the regression curve increases as the defect size increases.

Methods of calculation and testing of gas equipment. Lecture № 6. Part 5. Test method of gas equipment for CNG operation

2020 ◽  
Keyword(s):  
Natural Gas ◽  
Technological Process ◽  
Test Methods ◽  
Test Method ◽  
Schematic Diagram ◽  
Compressed Natural Gas ◽  
Certification Tests ◽  
Gas Cylinder ◽  
And Control ◽  
Gas Supply

The method of testing the gas supply systems of HBA for tightness and strength of connections is described. A schematic diagram of CNG accumulation is presented. Diagrams of test stands for compressed natural gas equipment are presented. A schematic diagram of checking the tightness of a singlefuel compressed natural gas supply system is presented. The technological process of checking the tightness of gas cylinder equipment in production conditions is presented. The technological process of inspection of a highpressure cylinder is given. The scheme of certification tests of a cylindrical CNG gas cylinder is shown. The scheme of certification and control of production of CNG cylinders is given. The diagram for testing and tightness of a twostage compressed natural gas reducer is given. Keywords rules and test methods; leakproofness; certification; singlefuel and dualfuel system; compressed natural gas; test modes; certification tests of the cylinder and gas equipment components; destruction of the cylinder

The threshold of sweet taste recognition among a sample of Moroccan population

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Yasmine Guennoun ◽  
Nada Benajiba ◽  
Khalid Elkari ◽  
Amina Bouziani ◽  
Laila Elammari ◽  
...  
Keyword(s):  
Age Groups ◽  
Sweet Taste ◽  
Test Method ◽  
Recognition Threshold ◽  
Taste Perception ◽  
Choice Test ◽  
Sample Population ◽  
Content Type ◽  
Mean Values ◽  
Moroccan Population

Purpose Sugar consumption in Morocco is high, which is involved in triggering serious health conditions. Hence, assessing the recognition threshold of sweet taste among Moroccans is strongly needed. This study aims to determine the threshold of sweet taste recognition and to evaluate differences by sex, age and body mass index among a sample of Moroccan population. Design/methodology/approach This single-blind trial was conducted among 199 healthy participants to determine the sweet taste. Age and anthropometric characteristics were registered. Nine sucrose solutions of the following concentrations (0; 0.111; 0.333; 1; 3; 9; 27; 81; 243 mmol/L) were prepared. Sweet taste perception thresholds were determined based on the validated 3-alternative forced choice test method. Findings The average age of the sample population was 21.5 ± 26.1. And more than half (51.7%) detected the taste at the concentration of 9 mmol/L, while 91.9% recognized it at a concentration of 27 mmol/L. In terms of sex, the recognition of taste was not different between females and males (p > 0.05). The mean values of the threshold among women were significantly lower (20 ± 20.8 mmol/L) compared to men (23.9 ± 33.2 mmol/L). The age group 49–59 years old had the lowest threshold with a mean of 13.4 ± 10.2 mmol/L, and the groups with BMI in the overweight category had mean of 16.9 ± 18.2 mmol/L. However, no statistical difference was observed among either age groups or BMI categories. Originality/value The sweet recognition threshold among the studied population is high. Therefore, it is strongly recommended to educate the population about the necessity of a progressive reduction of sugar in food items to combat non-communicable disorders.

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