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Increased agility for the research and development of dynamic roof support products
Published in Charlie C. Li, Xing Li, Zong-Xian Zhang, Rock Dynamics – Experiments, Theories and Applications, 2018
The limitation of a dynamic impact tester with respect to the simulation of an underground rock burst are clearly understood. However, “the main advantage of the drop test approach lies in the capacity to perform a relatively large number of tests at a reasonable cost without interfering with mining operations.” (Hadjigeorgiou & Yves 2011). Based on this, NCM commissioned the development of a drop tester capable of fulfilling the following requirements: low cost configuration, test a tendon system and capability to inducing failure in a single impulse. The low configuration cost allows for a large number of tests to be performed on the tendon system including the washer, nut and face plate. The ability to impart enough energy to induce failure in a single drop will allow the effects of the input parameters on the results of testing to be fully understood.
How Do We Test Rockets?
Published in Travis S. Taylor, Introduction to Rocket Science and Engineering, 2017
For vehicles that land like an airplane or even like the LEM on the Moon missions, they need to be tested as well. Landing and drop test are specifically useful in experimentally verifying the design of the landing gear of these vehicles. Figure 6.44 shows a landing test taking place at the NASA Aircraft Landing Dynamics Facility at Langley. This particular test examines how landing gear interacts with the runway during touchdown at high speeds.
Protective Headgear in Sports
Published in Youlian Hong, Routledge Handbook of Ergonomics in Sport and Exercise, 2013
Kevin Laudner, Robert C. Lynall
While the testing varies slightly between helmets of various sports, several factors remain constant. Headform impacts are measured via a triaxial accelerometer mounted at the centre of gravity of the headform. This accelerometer must provide measurements in three orthogonal axes and be able to provide appropriate measurements at severity index (SI) levels of ± 2 per cent across a range of 600–2,500. Severity index is a measure of the severity of impact with respect to the instantaneous acceleration detected by the headform during a collision. In order to calculate SI, the following formula is applied: SI=∫0TA2.5dt, where ‘A’ is equal to instantaneous resultant acceleration and ‘dt’ are time increments in seconds with the integration carried out over the essential duration of the acceleration pulse (NOCSAE, 2012j). The helmet must fit the headform in accordance with the helmet manufacturers’ specifications. Drop tests are conducted in various helmet locations after the equipment has been exposed to several temperatures, including ambient laboratory temperature of 22 ± 3°C and a high temperature environment in which the equipment is conditioned for a minimum of 4 hours at a temperature of 46 ± 3°C. Each piece of equipment has standard drop test impact velocities, ranging from 3.46 m.s−1 to 5.46 m.s−1, which must be achieved in order for the test to be considered valid (NOCSAE, 2012j). Standards also exist to test headgear against projectiles, such as a baseball, softball, or hockey puck. Projectile velocities for these tests range from 24.6 m.s−1 to 28 m.s−1 (NOCSAE, 2012a, 2012c). These standards are similar to the drop testing in that the headgear is exposed to impacts at various velocities and in multiple locations at both an ambient and high temperature condition.
Crashworthiness analysis of an aircraft fuselage section with an auxiliary fuel tank using a hybrid multibody/plastic hinge approach
Published in International Journal of Crashworthiness, 2020
Yi Yang Tay, Paulo Flores, Hamid Lankarani
Once the component level simulations and MB modelling of the fuselage are completed, an initial velocity of 9.14 m/s is assigned to the fuselage to simulate a 4.27 m vertical drop. The drop test is aimed to evaluate the structural integrity of the fuselage section in a severe, but survivable impact condition. The dynamic responses of the MB model such as the kinematic and dynamic behaviour of the cabin floor are obtained for comparison with the test article and FE model.