The characterisation and modelling of a double-layer dunnage bag

Bonsma, I. M. (2019-04)

Thesis (MEng)--Stellenbosch University, 2019.

Thesis

ENGLISH ABSTRACT: Dunnage bags are used to stabilize and secure cargo. Currently, the dunnage bags available are either single-layer dunnage bags which are expensive or inexpensive double-layer dunnage bags. However, due to the time-consuming production of a double-layer dunnage bag, an inexpensive single-layer dunnage bag material could be a viable alternative. The aim of the project is to develop a material criterion that can find candidate material properties that produce the same performance parameters as the current double-layer dunnage bags at the same cost. This material should provide the same properties and display the same behaviour at similar operating conditions as the original double-layer dunnage bag. Accordingly, a material criterion, that consists of parametric mathematical models, are developed. These models are developed using load cases that the dunnage bags experiences, along with various theoretical equations that are linked and validated by experiments. Large-scale experimental case studies and smaller swatch tests are performed to determine the actual behaviour and material properties of the double-layer dunnage bags. The experimental data of the tensile tests are analysed by using constitutive modelling. Finally, to create a material criterion, a Monte Carlo Simulation is used to input material properties, based on a normal distribution. Then, the material properties are fed into a pass criterion that is used to filter various material properties while being compared to the output of the model parameters. This finally leads to correlated candidate material properties.

AFRIKAANSE OPSOMMING: Stusakke word gebruik om vrag te stabiliseer en te beveilig. Tans is die stusakke beskikbaar in enkellaag sakke wat duur is of dubbellaagsakke wat goedkoper is. As gevolg van die tydrowende produksie van 'n dubbellaag stusak, word 'n goedkoper enkellaag stusakmateriaal ondersoek. Die doel van die projek is om 'n wesenlike kriterium te ontwikkel wat kandidaat materiaal eienskappe kan hê wat dieselfde prestasieparameters as die huidige dubbellaag stusakke teen dieselfde koste het. Hierdie materiaal moet dieselfde eienskappe verskaf en dieselfde gedrag vertoon by soortgelyke bedryfsvoorwaardes as die oorspronklike dubbellaagsak. Gevolglik word 'n wesenlike kriterium wat uit parametriese wiskundige modelle bestaan, ontwikkel. Hierdie modelle word ontwikkel met behulp van lasgevalle wat die stusakke ervaar, tesame met verskeie teoretiese vergelykings wat deur eksperimente gekoppel en gevalideer word. Grootskaalse eksperimentele gevallestudies en kleiner steekproewe word uitgevoer om die werklike gedrag van die dubbellaagsakke te bepaal. Die eksperimentele data van die trektoetse word ontleed aan die hand van konstitutiewe modellering. Ten slotte, om 'n wesenlike kriterium te skep, word die Monte Carlo Simulasie gebruik om insette van materiële eienskappe te stuur, gebaseer op 'n normale verspreiding. Dan word die materiaal eienskappe gevoer in 'n slaag of druip kriterium wat gebruik word om verskillende materiaal eienskappe te filtreer, terwyl dit vergelyk word met die uitset van die modelparameters.

Please refer to this item in SUNScholar by using the following persistent URL: http://hdl.handle.net/10019.1/106116
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