Behaviour of Multi-Layered Corrugated Paperboard Cushioning Systems under Impact Loads

2006 ◽  
Vol 3-4 ◽  
pp. 383-390 ◽  
Author(s):  
Michael A. Sek ◽  
Vincent Rouillard
Keyword(s):  
Extreme Events ◽  
High Speed ◽  
Shock Loading ◽  
Response Spectrum ◽  
Field Measurements ◽  
Mechanical Shocks ◽  
Impulsive Loads ◽  
Shock Response ◽  
Original Field ◽  
Shock Response Spectrum

This paper presents some of the latest results of a research project aimed at using composite corrugated paperboard structures for protection of products against mechanical shocks and vibration during transportation and handling. Specifically, the behaviour of multi-layered corrugated paperboard (MCPB) under shock loading is investigated. Conventionally, packaging cushion design requires the determination of the maximum expected shock levels or equivalent drop which are usually determined from statistical analysis of original field measurements. With this approach, it is generally acknowledged that the cushioning element is engineered to provide adequate protection for statistically likely events but not for extreme events with low statistical likelihood. It is reluctantly accepted that, should it occur, the latter will result in damage to the product. MCPB can be formed with a broad range of compressive characteristics and with various proportions of elastic and plastic behaviour. The objective of this experimental investigation was to determine the optimum elastic/plastic proportion to extend the protective range to include large shock levels. The experimental results obtained include the effects of compression history on the stress-strain properties of MCPB as well as the behaviour of the material in both virgin and pre-compressed form under impulsive loads. The mechanism of deformation of the corrugations (flutes) was studied using high-speed video equipment. The complex acceleration signals produced during deformation of the composite corrugated paperboard cushions under shock loading were analysed by means of the shock response spectrum. Experiments have shown that inserting a sacrificial crumple element of virgin corrugated paperboard at the optimum contact area ratio dramatically lowers the overall level of the resulting shock response spectrum. This has the effect of increasing the allowable drop height for a limited number of extreme events. The main conclusion of the research is that MCPB in both virgin and pre-compressed forms can be combined to provide significantly enhanced protection to products against mechanical hazards during distribution.

Critical Shock Response Spectrum of a Beam Under Shock Loading

2016 ◽  
Author(s):  
Bingwei Li ◽  
Qingming Li ◽  
Bo Liu ◽  
Zhiling Niu ◽  
Zijun Nangong ◽  
...  
Keyword(s):  
Shock Loading ◽  
Response Spectrum ◽  
Offshore Structures ◽  
Shock Response ◽  
Shock Response Spectrum ◽  
Shock Environment ◽  
Severe Shock ◽  
Structural Failures ◽  
Structural Engineers ◽  
The Relationship

The offshore structures experience severe shock environment caused by storms, episodic waves, icebergs or supply ships. The aerospace equipment may also encounter severe shock loadings due to pyrotechnic shock. The intensive shock causes structural failures, or even results in fatal consequences on the related facilities and persons. Therefore it is important to study the response and the damage behavior of structures under shock loading. The damage boundary of a beam under shock is studied, based on the structural dynamics and the shock response spectrum analysis. The relationship between the critical real velocity and the critical pseudo velocity is investigated, and the concept of loading factor is proposed. A simple and practical rule of estimating structure fragility is developed based on the pseudo velocity shock response spectrum and the loading factor. The explicit numerical simulation of a beam under shock loading is carried out using LS-DYNA. The critical shock response spectrums as well as the loading factor of the beam is obtained. This paper has an important significance of helping structural engineers to design the offshore and aerospace equipment under shock environment.

scholarly journals Aspects of Strength Testing of Tank Containers in Compliance with the Requirements of the UN Navigation Rules and Regulations

2021 ◽  
Vol 9 (3) ◽  
pp. 349
Author(s):  
Andrii Sulym ◽  
Pavlo Khozia ◽  
Eduard Tretiak ◽  
Václav Píštěk ◽  
Oleksij Fomin ◽  
...  
Keyword(s):  
Natural Frequencies ◽  
Response Spectrum ◽  
Experimental Curve ◽  
Bulk Liquid ◽  
Frequency Range ◽  
Test Configuration ◽  
Shock Response ◽  
Shock Response Spectrum ◽  
Spectrum Curve ◽  
The Impact

This article deals with the method of computer-aided studies of the results of tank container impact tests to confirm the ability of portable tanks and multi-element gas containers to withstand the impact in the longitudinal direction on a specially equipped test rig or using a railway flat car by impacting a flat car with a striking car, in compliance with the requirements of the UN Navigation Rules and Regulations. It is shown that the main assessed characteristic of the UN requirements is the spectrum of the shock response (accelerations) for the interval natural frequencies of the shock pulse. The calculation of the points of the shock response spectrum curve based on the test results is reproduced in four stages. A test configuration of the impact testing of the railway flat car with a tank container is presented, and the impact is performed in such a way that, under a single impact, the shock spectrum curve obtained during the tests for both fittings subjected to impact repeats or exceeds the minimum shock spectrum curve for all frequencies in the range of 2 Hz to 100 Hz. Formulas for determining the relative displacements and accelerations for the interval natural frequencies of the shock wave are given. The research results are presented in graphical form, indicating that the experimental values of the shock response spectrum exceed the minimum permissible values; the equation of the experimental curve of the shock response spectrum in the frequency range 0–100 Hz is described by power-law dependence. The coefficients of the equation were determined by the statistical method of maximum likelihood with the determination factor being 0.897, which is a satisfactory value; a comparative analysis showed that the experimental curve of the impact response spectrum in the frequency range 0–100 Hz exceeds the normalized curve, which confirms compliance with regulatory requirements. A new test configuration is proposed using a tank car with a bulk liquid, the processes in which upon impact differ significantly from other freight wagons under longitudinal impact loads of the tank container. The hydraulic impact resulting from the impact on the tank container and the platform creates an overturning moment that causes the rear fittings to be unloaded.

Overview: High Speed Dynamics and Modelling as It Applies to Energetic Solids

1992 ◽  
Vol 296 ◽  
Author(s):  
J. Covino ◽  
S. A. Finnegan ◽  
O. E. R Heimdahl ◽  
A. J. Lindfors ◽  
J. K. Pringle
Keyword(s):  
Energetic Materials ◽  
High Speed ◽  
Shock Loading ◽  
Dynamic Deformation ◽  
Two Dimensional ◽  
State Data ◽  
Impact Modelling ◽  
Shock Response ◽  
Hazard Assessments ◽  
Reaction Thresholds

AbstractThis paper discusses experimental techniques and modelling tools used to characterize energetic solids subjected to dynamic deformation and shock. Critical experiments have been designed to study shock response and impact sensitivity of energetic materials. For example, a simplified two dimensional experiment has been developed to study the critical phenomena involved in delayed detonation reactions (XDT). In addition, wedge tests are used to obtain equation-of-state data. Coupled with hydrocodes, these experiments give us an in-depth understanding of the response of energetic materials subjected to shock loading. A coupled methodology using both experimental and modelling tools is presented. Consisting of three parts, it addresses all possible responses to fragment impact. The three parts are: (1) Fragment impact modelling (hydrocodes and empirically based codes); (2) Experiments to obtain accurate data for predicting prompt detonation; and (3) Tests with planar rocket motor models to explore mechanisms related to bum reaction thresholds and degree of violence. This methodology is currently being used in weapon design and munitions hazard assessments.

Analytical Determination of Shock Response Spectra for an Impulse-Loaded Proportionally Damped System

Volume 1 ◽  
2004 ◽  
Author(s):  
R. David Hampton ◽  
Nathan S. Wiedenman ◽  
Ting H. Li
Keyword(s):  
Transient Response ◽  
Shock Loading ◽  
Response Spectrum ◽  
Response Spectra ◽  
Analytical Determination ◽  
System Response ◽  
Mechanical Shock ◽  
Shock Response ◽  
Mass Spring ◽  
The Impact

Many military systems must be capable of sustained operation in the face of mechanical shocks due to projectile or other impacts. The most widely used method of quantifying a system’s vibratory transient response to shock loading is called the shock response spectrum (SRS). The system response for which the SRS is to be determined can be due, physically, either to a collocated or to a noncollocated shock loading. Taking into account both possibilities, one can define the SRS as follows: the SRS presents graphically the maximum transient response (output) of an imaginary ideal mass-spring-damper system at one point on a flexible structure, to a particular mechanical shock (input) applied to an arbitrary (perhaps noncollocated) point on the structure, as a function of the natural frequency of the imaginary mass-spring-damper system. For a response point sufficiently distant from the impact area, many Army platforms (such as vehicles) can be accurately treated as linear systems with proportional damping. In such cases the output due to an impulsive mechanical-shock input can be decomposed into exponentially decaying sinusoidal components, using normal-mode orthogonalization. Given a shock-induced loading comprising such components, this paper provides analytical expressions for the various common SRS forms. The analytical approach to SRS-determination can serve as a verification of, or an alternative to, the numerical approaches in current use for such systems. No numerical convolution is required, because the convolution integrals have already been accomplished analytically (and exactly), with the results incorporated into the algebraic expressions for the respective SRS forms.

Swept Sine Vibration Test Conservatism

1995 ◽  
Vol 38 (6) ◽  
pp. 13-17
Author(s):  
M. Hine
Keyword(s):  
Response Spectrum ◽  
Three Dimensional ◽  
Test Method ◽  
Vibration Test ◽  
Transient Vibration ◽  
Mass Model ◽  
Dynamic Mass ◽  
Shock Response ◽  
Order Of Magnitude ◽  
Shock Response Spectrum

The excessive overtest associated with the swept sine vibration test method was measured quantitatively using the index of conservatism and the associated overtest factor for a dynamic mass model of a typical spacecraft component. The response to a fixed amplitude sine sweep test was compared with the flight transient vibration environment for sweep rates of 2, 4, and 6 octaves/min and 300 Hz/min. A response-limited test was also conducted at 6 octaves/min. The conservatism was measured using several characterizations; namely: number of peaks exceeding, ranked peaks, shock response spectrum, shock intensity, three-dimensional shock response spectrum, and ranked peaks. Overtest factors exceeding an order of magnitude were measured for the test response with the number of peaks exceeding and the three-dimensional shock response spectrum.

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