Browsing by Author "Venter, Martin Philip"

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    Development and validation of a numerical model for an inflatable paper dunnage bag using finite element methods
    (Stellenbosch : University of Stellenbosch, 2011-03) Venter, Martin Philip; Venter, Gerhard; University of Stellenbosch. Faculty of Engineering. Dept. of Mechanical and Mechatronic Engineering.
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    A methodology for numerical prototyping of inflatable dunnage bags
    (Stellenbosch : Stellenbosch University, 2015-03) Venter, Martin Philip; Venter, Gerhard; Stellenbosch University. Faculty of Engineering. Dept of Mechanical and Mechatronic Engineering.
    ENGLISH ABSTRACT: Dunnage bags are an inflatable dunnage variant, positioned and inflated between goods in multi-modal containers to restrain and protect the goods while in transit. This project endeavours to develop a simple method of generating new numerical prototypes for dunnage bags suitable for simulating operational loading of the bags. Previous research has produced a model that simulates the inflation of a paper dunnage bag using a simple pressure load. A dunnage bag reinforced with plain-woven polypropylene was chosen as the test case. Woven polypropylene is a highly non-linear, non-continuous, non-homogeneous material that requires specialised material models to simulate. A key aspect of this project was to develop a simple method for characterising woven-polypropylene and replicating it's response with material models native to LS-DYNA. The mechanical response of the plain-woven polypropylene was tested using a bi-axial tensile test device. The material response from physical testing was then mapped to two material models using the numerical optimiser LS-OPT. The response of the calibrated material models was found to correlate well with the measured response of the woven material. Dunnage bags are subjected to cyclic loading in operation. In order to capture the effects of compressing the contained gas, a gas inflation model was added to the model that calculates the pressure in the bag based on the Ideal Gas Law. A full bag model making use of the calibrated material models and the inflation model was subjected to a cycled boundary condition simulating loading and unloading of an inflated dunnage bag. The two prototype models captured the pressure drop in the bag due to material plastic deformation and the restraining force produced by the bag to within 10 %. The prototype models were also found suitable for predicting burst pressure in voids of arbitrary size and shape.