Vibration Testing of Intermediate Bulk Containers for Dangerous Goods

Intermediate bulk containers (IBCs) for liquid dangerous goods require a vibration test for type approval introduced in the United Nations Recommendations on the transport of dangerous goods. The test has to be performed as a repetitive shock test practically identical to the test procedure previously prescribed by the US Department of Transport. It is conceptually simple but has several drawbacks. The kinetics and dynamics of a bouncing IBC have been investigated by means of simple computational models. With increasing complexity, partially plastic impact, elastodynamic response and the excitation of internal vibrations not directly affected by the bounces can be covered. The latter is a model for the sidewall vibrations. The numerical results show that the control over the specimens' response is only partially defined in the test procedure. Chaotic movements at resonance are possible and must be suppressed by changing the test parameters, which is mostly left to the test engineer. Accordingly, it is not possible to interpret the test results with a sound relation to real transport vibration environment. Experimental results, however, suggest that vibration testing of IBCs improves safety because resonance effects in a frequency range excited by typical transportation loads exist. A more detailed numerical model is necessary for the assessment of the fatigue damage imposed on IBCs by the prescribed or alternative, more realistic test procedures. Copyright (c) 2011 John Wiley & Sons, Ltd.