Energy absorbed by elastic waves during impact

Hunter, Simon C.

doi:10.1016/0022-5096(57)90002-9

Cited by 303 publications

(130 citation statements)

References 2 publications

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“…After the reflection from target borders, the wave comes back towards the contact area. If the contact time is longer than the period of wave propagation through the plate from contact point to the bottom wall of plate and return to the contact point then the waves will reach the contact partners and lead to loss of kinetic energy which was first calculated by Hunter [33]. Because of reflected waves the granule looses additional energy which leads to a decrease of the restitution coefficient.…”

Section: Apparatus and Methods For Free-fall Experimentsmentioning

confidence: 99%

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Energy absorption during compression and impact of dry elastic-plastic spherical granules

et al. 2010

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The discrete modelling and understanding of the particle dynamics in fluidized bed apparatuses, mixers, mills and others are based on the knowledge about the physical properties of particles and their mechanical behaviour during slow, fast and repeated stressing. In this paper model parameters (modulus of elasticity, stiffness, yield pressure, restitution coefficient and strength) of spherical granules ( γ -Al 2 O 3 , zeolites 4A and 13X, sodium benzoate) with different mechanical behaviour have been measured by single particle compression and impact tests. Starting with the elastic compression behaviour of granules as described by Hertz theory, a new contact model was developed to describe the force-displacement behaviour of elastic-plastic granules. The aim of this work is to understand the energy absorption during compression (slow stressing velocity of 0.02 mm/s) and impact (the impact velocity of 0.5-4.5 m/s) of granules. For all examined granules the estimated energy absorption during the impact is found to be far lower than that during compression. Moreover, the measured restitution coefficient is independent of the impact velocity in the examined range and independent of the load intensity by compression (i.e. maximum compressive load). In the case of repeated loading with a constant load amplitude, the granules show cyclic hardening with increasing restitution coefficient up to a certain saturation in the plastic deformation. A model was proposed to describe the increase of the contact stiffness with the number of cycles. When the load amplitude is subsequently increased, further plastic deformation takes place and the restitution coefficient strongly decreases.

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Section: Apparatus and Methods For Free-fall Experimentsmentioning

confidence: 99%

“…The Hertzian contact theory of the elastic spheres has certain restrictions regarding description of a dynamic collision [33]. The first condition of this theory can be formulated as follows: the contact pressure must increase slow enough to consider the quasi-static conditions.…”

Section: Introductionmentioning

confidence: 99%

Energy absorption during compression and impact of dry elastic-plastic spherical granules

et al. 2010

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“…1 Kinetics of the box system under drop impact In this equation, μ i,s and E i,s are the Poisson's ratio and Young's modulus of the impactor and the impacted surface, respectively. Analytical solution for equation (5) is impossible due to the high nonlinearity, but Hunter [11] provides an approximation for δ and F as a semi-sinusoidal progression over the contact time T i :…”

Section: System Kineticsmentioning

confidence: 99%

Experimental and Analytical Study of Free-Fall Drop Impact Testing of Portable Products

2012

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Portable products can suffer critical damage due to drop impact and thus, such load cases must be taken into account in the conceptual and detailed design phases of such products. One method explored in the current study for alleviating the peak accelerations resulting from impact is to isolate fragile components from the product housing using internal shock mounts. There is a lack of studies that address this method in a systematic and reliable manner. This paper presents an experimental and analytical study on the dynamic behaviour during impact of portable products with internal shock mounting. Using a special drop tower with guiding frame for controlled-angle free-fall drop impact, representative products are dropped at different angles and the acceleration is recorded both on the outer case and on an internally-mounted plate. A simplified analytical procedure, suitable for conceptual design purposes, is proposed for predicting the resulting dynamic response. The work affirms the suitability of guide-and-release facilities in impact experiments; additionally, it may facilitate the conceptual design for impact resistance of portable products.

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“…As defined by Hunter [12], an impact half-space case is the situation where the projectile mass is very small with respect to the mass of the impacted structure. Consequently there is little motion of the structure and then the impact response is considered to be localized [1,8,13,14].…”

Section: Half-space Casementioning

confidence: 99%

Estimation of the Impact Duration for Several Types of Structures

Jacquelin

Pashah

Lainé

et al. 2012

Shock and Vibration

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Abstract. The impact duration between two structures is not easy to forecast. Indeed it depends on many parameters including local parameters as well as structural parameters which characterize the dynamics of the structures.In this paper we will show that it is possible to have a prior estimation of the impact duration. In fact the simulations show that this parameter is connected to some characteristics of a specific model, the so-called antioscillator model, even for the complex case of the impact between two flexible structures. All the simulations carried out on different cases show the close relationship between the first impact duration and the antioscillator characteristics. However some limitations exist and have been highlighted.

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Energy absorbed by elastic waves during impact

Cited by 303 publications

References 2 publications

Energy absorption during compression and impact of dry elastic-plastic spherical granules

Energy absorption during compression and impact of dry elastic-plastic spherical granules

Experimental and Analytical Study of Free-Fall Drop Impact Testing of Portable Products

Estimation of the Impact Duration for Several Types of Structures

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