Simple Impact Test Research Articles

An Experimental Comparison of Simple Measurements Used for the Characterization of Sand Equestrian Surfaces.

Simple SummaryConsistency of equestrian surfaces can contribute to safety and performance. An optimal surface is influenced by the design and material selection as well as maintenance and climate. To improve surfaces the quantitative testing of functional surface properties must expand beyond the current testing at the highest levels of competition. More widespread quantitative measurements would have a positive influence on animal welfare and rider safety. To expand beyond the current top levels of the sport, simple tools are required that can be shown to detect relevant changes in construction and maintenance. Our work suggests that the appropriate use of simple devices can help with both quality control of new surfaces and the monitoring of existing surfaces. Performance modifications to the layered surface design and addition of Geotextile were detected using the Going Stick and a simple impact test. These measured results are also influenced by other factors related to the surface condition such as moisture. Caution must be exercised in the interpretation of the results since these tools have not been demonstrated to correlate to either performance or safety of the surface. However, these results are encouraging and provide a justification for future development of this type of equipment.Quantitative measurements of performance parameters have the potential to increase consistency and enhance performance of the surfaces as well as to contribute to the safety of horses and riders. This study investigates how factors known to influence the performance of the surface, incorporation of a drainage package, control of the moisture control, and introduction of a geotextile reinforcement, affect quantitative measurements of arena materials. The measurements are made by using affordable lightweight testing tools which are readily available or easily constructed. Sixteen boxes with arena materials at a consistent depth were tested with the Going Stick (GS), both penetration resistance and shear, the impact test device (ITD), and the rotational peak shear device (RPS). Volumetric moisture content (VMC %) was also tested with time–domain reflectometry (TDR). Results obtained using GS, RPS, ITD, and TDR indicate that the presence of the drainage package, moisture content, and geotextile addition were detected. Alterations due to combinations of treatments could also be detected by GS, ITD, and TDR. While the testing showed some limitations of these devices, the potential exists to utilize them for quality control of new installations as well as for the monitoring of maintenance of the surfaces.

Additive manufacturing of single- and double-layer piezoelectric PVDF-TrFE copolymer sensors

Abstract The sensitivity of piezoelectric PVDF sensors is directly related to the concertation and orientation of the polar phases. Previous efforts in obtaining oriented polar phases during 3D printing proved to be challenging. In this paper the superiority of the co-polymer PVDF-TrFE when compared to PVDF for 3D printing is demonstrated. In contrast to PVDF, PVDF-TrFE forms nearly pure β-phase in solidification from melt. The emergence of more β-phase than the non-polar α-phase is demonstrated with XRD results. 3D printed double-layer samples were produced consisting of one electroactive layer of PVDF-TrFE, and a non-electroactive substrate and protective layer of PVDF. The 3D printed samples were poled with corona discharge to produce output signals up to 130V DC peak-to-peak from a simple impact test (flicking) on a 20×30 mm sample. We also observed high sensitivity to 2mm dynamic displacement loads that produced ~19V. The results presented here are considerably higher than any reported results from other additive manufacturing methods.

Determination of the Material Properties of Recycled Rubber for Explicit FEM Simulation

Recycled rubber materials are one of cheap and suitable materials for energy absorbers in protective structures. Standard tests of elastomers in uniaxial or biaxial tension is not suitable and efficient for energy absorbers made of recycled car tires. Simple compression test and simple impact test are described material properties from those tests are determined and compared with simulation in ANSYS/AUTODYN.

Dynamic Inter-Particle Force Inference in Granular Materials: Method and Application

Inter-particle force transmission in granular media plays an important role in the macroscopic static and dynamic behavior of these materials. This paper presents a method for inferring inter-particle forces in opaque granular materials during dynamic experiments. By linking experimental measurements of particle kinematics and volume-averaged strains to forces, the method provides a new tool for quantitatively studying force transmission and its relation to macroscopic behavior. We provide an experimental validation of the method, comparing inter-particle forces measured in a simple impact test on two-dimensional rubber grains to a finite-element simulation. We also provide an application of the method, using it to study inter-particle forces during impact of an intruder on a granular bed. We discuss the current challenges for applying the method to both model materials and real geologic materials.

THE EFFECTIVENESS OF THE COMPONENT IMPACT TEST METHOD FOR THE SIDE IMPACT INJURY ASSESSMENT OF THE DOOR TRIM

The complete evaluation of the side vehicle structure and the occupant protection is only possible by means of the full scale side impact crash test. But, auto part manufacturers such as door trim makers can not conduct the test especially when the vehicle is under the developing process. The main objective of this study is to obtain the design guidelines by a simple component level impact test. The relationship between the target absorption energy and impactor speed were examined using the energy absorbed by the door trim. Since each different vehicle type required different energy levels on the door trim. A simple impact test method was developed to estimate abdominal injury by measuring reaction force of the impactor. The reaction force will be converted to a certain level of the energy by the proposed formula. The target of absorption energy for door trim only and the impact speed of simple impactor are derived theoretically based on the conservation of energy. With calculated speed of dummy and the effective mass of abdomen, the energy allocated in the abdomen area of door trim was calculated. The impactor speed can be calculated based on the equivalent energy of door trim absorbed during the full crash test. With the proposed design procedure for the door trim by a simple impact test method was demonstrated to evaluate the abdominal injury. This paper describes a study that was conducted to determine sensitivity of several design factors for reducing abdominal injury values using the matrix of orthogonal array method. In conclusion, with theoretical considerations and empirical test data, the main objective, standardization of door trim design using the simple impact test method was established.

A finite element model for impact simulation with laminated glass

A computational technique for the modelling of laminated safety glass is presented using an explicit finite element solver. Coincident finite elements are used to model the layered set-up of laminated glass: shell elements with brittle failure for the glass components and membrane elements to simulate the ultimate load carrying capacity of the PVB-interlayer. Two different approaches are considered to model laminated glass: a physical model and a smeared model. In the physical model the glass is considered as elastic/brittle and the interlayer as a hyperelastic material. For the hyperelastic description of the interlayer, we give an overview of material models, which are widely used for explicit solvers, i.e. the laws by Blatz–Ko, Mooney–Rivlin and Ogden. The obtained stress–strain curves are fitted to experimental results of the interlayer. The hyperelastic model is applied to a simple impact test demonstrating the numerical robustness. In the smeared model, we use two shell elements of equal thickness with elasto-plastic material properties to obtain an improved bending response after fracture. For validation, experimental investigations have been carried out where a spherical impactor was shot against a windscreen. The acceleration of the impactor has been measured in this test and is compared to the numerical results.

On a simple impact test method for accurate measurement of material properties

A simple impact test method is presented to accurately measure the elastic and shear moduli and Poisson's ratio of a uniform Aluminum 6061-T651 cylindrical specimen with free boundary conditions. The elastic modulus is determined from the longitudinal vibration of the specimen and the shear modulus is determined from its torsional vibration. A new technique is developed to mount an accelerometer on the specimen to measure its torsional vibration. The Poisson's ratio determined for the specimen matches exactly with its known value.

鋼材の繰り返えし衝撃におけるせん移温度について

Repeated bending impact tests were carried out with test pieces of a rimmed steel at -40°C-30°C. It was found that, in the case where test pieces were broken at the repeated number fewer than 103, the transition temperature appeared at about 0°C. and did not appear at more than 103. The trasition domain of the case where the cleavage was assumed to be made by the last one impact under repeated impact test was higher than that in case of simple impact test.