Pulse Shape and Duration in Frontal Crashes

Warner, Charles Y.; Warner, Mark H.; Crosby, Charles L.; Armstrong, Michael J.

doi:10.4271/2007-01-0724

Cited by 7 publications

(8 citation statements)

References 22 publications

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“…For example, the contact to the ground (stiffness, damping properties) are crucial and should not be neglected. This is also evident in Equation (11) (given by substituting the mass ratio MR in Equation 4), which relates eigenfrequency f 0 to stiffness k, mass ratio MR, and mass of packaging m 1 .…”

Section: Parametric Model Based On Maximum Rigid Body Deflectionmentioning

confidence: 86%

“…This effect is described by the characteristics of the impact force F impact and depends on the properties of the packaging, such as deformability and drop position. 10,11 In Figure 9, an example of an impact pad vibration is shown, which corresponds to the rigid body motion assumption described in Equation (3). Equations ( 5)-( 8) are used to derive the first maximum velocity value of the impact target _ d t 1 ð Þ considering the law of conservation of momentum 12 at time t ¼ t 1 and t ¼ t 2 (see Equation 5).…”

Section: Parametric Model Based On Maximum Rigid Body Deflectionmentioning

confidence: 99%

“…Lastly, the terms J Dt 1 , J Dt 2 , and ΔJ D relate to the impulse of deformation 11,12 caused by the impact force F impact in the time periods Δt 10 ¼ t 1 À t 0 , Δt 20 ¼ t 2 À t 0 , and Δt 21 ¼ t 2 À t 1 , respectively.…”

Section: Parametric Model Based On Maximum Rigid Body Deflectionmentioning

confidence: 99%

“…Packaging characteristics such as material properties and drop position are very important as well. Furthermore, the stiffness of the impact target's connection to the ground is essential and should not be neglected considering Equations ( 10) and (11), that is, significantly higher stiffness of the connection to the ground results in significantly lower deflection values. Consequently, a mass ratio of 1:50 on its own is not a necessary criterion.…”

Section: Validation Of Parametric Model Based On Maximum Rigid Body D...mentioning

confidence: 99%

“…Both new criteria need to be fulfilled for the impact target in 2. However, the deflection ratio function f α, MR, ζ ð Þyields a value of f ¼ 1:3 according to Equation (11); the second criterion is not satisfied.…”

Section: Example Of Application In Practicementioning

confidence: 99%

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Improved criteria for evaluating impact targets in regulative drop tests of dangerous goods packagings

et al. 2023

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For dangerous goods packagings, drop testing onto an essential unyielding target can be used to assess the mechanical resistance to impact loads. Adopted regulations like Agreement concerning the International Carriage of Dangerous Goods by Road (ADR)/Regulation concerning the International Carriage of Dangerous Goods by Rail (RID) require that the impact surface provided shall be integral with a mass at least 50 times than that of the heaviest package to be tested. The problem is that many manufacturers do not possess impact targets that satisfy the required 50 times mass ratio for regulative drop tests during series production. The objective of this work is to verify existing and define improved criteria for impact target structures based on systematic investigations. Previous evidence highlights the relevance of other parameters in addition to the mass ratio. Therefore, in this research, a variation of drop test parameters was carried out experimentally. Furthermore, numerical vibration analysis was applied to investigate the deformability of the impact surface. The results conclude that the mass ratio of 1:50 cannot be defined as a decisive criterion. In order to determine the influence of further drop test parameters, the research findings were used to validate a parametric model that assesses impact target deflection. An approximation quality of over 90% was achieved. As a result, new evaluation criteria are proposed. First, a method for identifying critical impact target designs is provided. Second, a new comprehensive formula compares the approximated maximum deflection of a real impact target to the respective theoretical threshold derived from a worst‐case assumption. In practice, this leads to great advantages in the evaluation of already installed impact targets for dangerous goods packagings.

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Section: Parametric Model Based On Maximum Rigid Body Deflectionmentioning

confidence: 86%