Transport vibration laboratory simulation: On the necessity of multiaxis testing

Abstract

Nowadays, the packaging industry, like many other sectors, is coping with new demands resulting from fi nancial and environmental constraints. The importance of accurate laboratory simulation of transport vibration as a tool for packaging optimization is therefore increasing, as is highlighted by the International Safe Transit Association testing procedures (ISTA series). In this context, many studies can be found in the literature focusing on the special nature of transport vibrations, analysing the most suitable power spectral density profi les related to route and vehicle characteristics and the best statistical description for acceleration in order to achieve realistic simulation in the laboratory. Most of these works deal only with vertical vibrations because of the of the high energy content such vibrations represent, and only a limited number also analyse longitudinal and transversal acceleration spectra. This paper describes a non-comprehensive set of measurements in real transport situations with the purpose of providing an initial description of the six-degrees-of-freedom vibration produced inside a truck trailer. In addition, the importance of nonvertical random excitation is investigated in the laboratory by means of a multiaxis shaker table used to study the difference in the dynamic response of corrugated containers in stacked shipping units. The results show that the amount of energy neglected using only vertical testing procedures can be signifi cant, and that the packaging bending modes are not excited as they would be in a real transport situation. This demonstrates the necessity of multiaxis testing.

Measuring the mechanical and climatic conditions encountered by palletized products in handling and transport

“…Then, a testing machine has to be able to analyse the dynamic behaviour of a load when all these directions are combined. In this sense, in [52] it is recommended the use of a 6 degree of freedom (DoF) shaking table, in addition to the simultaneous detection on a large number of points on trailer. The research showed, once more, that the real movements of the truck load bed during transport cannot be properly described with vertical acceleration alone.…”

Dynamic Performance of Stacked Packaging Units

“…The effects of vertical restraint tension and stiffness were taken into account . Bernad et al investigated the dynamics of different corrugated stacked packaging units by means of operational modal analysis technique and a 6 degrees of freedom multi‐axis shaker table to demonstrate the necessity of multiaxis testing …”

Some characteristics of the heave, pitch and roll vibrations within urban delivery routes

“…To date, two publications compare the results of simulated uniaxial (heave) and multi‐axial vibrations of various packaging systems and identify important differences in the excitation of lateral mode shapes of staked packaging units and overall load stability. Attempts at evaluating the level and character of pitch and roll vibrations have been limited to a few observations .…”