Delft University of Technology
Faculty Mechanical, Maritime and Materials Engineering
Transport Technology

Y.S. Chan De inklapbare container. Verificatie hangstangenconcept.
Engineering Assignment, Report 2003.TT.5639, Transport Technology.

The research project "The collapsible container", of the Port of Rotterdam and Delft University of Technology, revealed logistical and financial opportunities of using collapsible containers. At this moment, many containers are transported while they are empty. By using the collapsible container, five containers can be stored as one.
In the same project, several concepts of this container are generated. One of them, "crossbars", is promising and already patented. However, more research and development is necessary before the container can be launched into the market.

The tasks are very diverse. It contains aspects of construction, simulation and creativity as well.
The concept of the crossbars must be worked out constructively. Moreover, we are interested in the folding process of the container, which must be validated by means of the multi-body program ADAMS. ADAMS should also be used to find the best solution for the container concerning the link between the roof and the sidewalls. Furthermore solutions need to be generated in order to set up the container.

The results of the simulations are summarized in an appendix to the report. The dynamic behavior of the crossbars concept appears to be quite similar with the concept of plates. For constructive reasons, the crossbars concept is chosen for further examination.
The (reaction) forces in the simulation are used to calculate the dimensions of the bars in the container. Detailed drawings of the construction (made in Pro-Engineer) are contained in an appendix to the report.
To set up the container, several ideas are developed. According to a simulation, setting up the container can simply be done manually. Concerning safety aspects, the working conditions in the harbors are quite rough (e.g. the twist locks are still being handled by hand below a loaded container). So it is open for discussion. Another solution makes use of elastic cables. These will be stretched while lifting the roof. The cables are attached in a specific way to pull out the walls at the desired moment. This system is safe and can efficiently be carried out by one person. However, the implementation of the cables may increase the costs of the container.

The simulation model is slightly restricted in use. The reliability of the maximum and minimum forces may be insecure. These lacks however, are inevitable due to the nature of the problem. Consequently some parameters cannot be found at the desired accuracy. Moreover the force vector substituting a joint is necessary to avoid a redundant constraint (which in this case will crash the model). This resuits in a higher local error in the integration process. Therefore, a high safety factor should be applied for the maximum and minimum forces (concerning the bars, a safety factor of five is applied).
The validation of the folding process is based on the results of the simulation, as well as the associated analyses and plausible interpretation of the results, assumed positively.

The simulation model appears to be of great help for tracing problems. However, the obtained results are not proportional to the invested time. Practically, one should carefully consider whether there is a balance between the problem and the time needed.

Reports on Transport Engineering (in Dutch)
Modified: 2003.02.16; , TU Delft / 3mE / TT / LT.