ABSTRACT
The rigidity of materials in conjunction with the aspect of elasticity has been a concern of modern technologies and construction in recent centuries because of the advantages that expandable storage would bring to the fields of containment units with respect to population growth and space exploration. The world population is currently growing at an exponential rate, and as our population grows, the more important it will become to have containment units that can both contain large volumes of material as well as minuscule amounts of material without wasting space.
In order accomplish this, we will need a new type of storage container that utilizes the inherent strengths of both flexibility and rigidity to find a unique balance between the two. The purpose of this study is not to necessarily find the final answer to the question of expandable storage, but to narrow the range of questions that later research will use to finally answer the question, “How will we do it?” In order to research the utility of elastic material in creating storage devices in the same manner as has have described, this study would create an expandable backpack as a scaled-down case study.
The backpack utilizes grooved panels made of lightweight, rigid material such as PVC-plastic in conjunction with elastic cloth, made of a mix of nylon and spandex, to create a container that will stand rigid on its own, but also expand in horizontal directions so that it can hold objects larger than its original volume. By creating male and female connectors in the individual panels, the container will be able to stand rigid, but also expand using elastic cloth sandwiched between the halves of each panel. The front and back of the container will be made of two panels, but the sides will be made up of 4 panels, so that expansion is more likely to occur in those directions, as well as lessen the stress on the fabric.
In order to create the container, the team sampled multiple ratios of nylon-to-spandex, as well as tested the rigidity of different woods and plastics. Upon deciding on a material, PVC, a prototype was built and tested. The testing process involved filling the container to with varying amounts of weight, such as textbooks and laptops, and having a test subject walk around carrying the objects for varying amounts of time. The study also tested the amount of volume the backpack is able to expand, aiming for between five and ten percent increased volume. While the purpose of this study is not to solve the problem of expandable storage definitively, the concept of elastic cloth between interlocking panels has a high likelihood of being a step in the right direction.
PROBLEM DEFINITION
In order to combat the eventual side-effects of overpopulation, an expandable container that can rest at a small volume and can expand to hold a larger volume while still retaining its structural needs to be designed. As such, the Expandable Containing and Holding Unit, or E.C.H.U. as it will now be referred to for the sake of readability, is a containment unit that has a state of equilibrium, but can reach states of higher capacities and larger internal volumes when such demands are in place. Immediately identifiable applications would be mailing packages, shipping containers, long-term storage units, and space traversing storage systems.
DESIGN REQUIREMENTS
ECHU is required to be a rigid, stand-alone structure when under no duress, but maintain structural integrity when at the limitations of its expandability. It also must be highly water resistant to better protect the contents. ECHU will have one partition of access via a sealable lid. For immediate testing, ECHU will be a Liberty University Engineering student’s backpack for two days. As such, ECHU must also have straps that are adjustable in length to better accommodate the comfort of the user. A backpack design was settled upon, versus a shipping container, due to ease in transport and budget limitations.
FEASIBILITY
For each phase of the Project, certain deadlines had to be met. For the benefit of all members on the ECHU Team, soft deadlines were set up for each individual member so as to complete each hard deadline within an appropriate time constraint. Deadlines for each member were set a couple of days before the hard deadlines set by Liberty University to allow for any unforeseen delays or complications, as well for formatting and editing when all pieces were brought together.
CONCEPTUALIZATION
Mrs. Carolyn Ziebart, professor of Engineering at Liberty University, agreed to be the project’s faculty mentor, and directed the team to talk to her husband, Mr. Ziebart. He has been a Mechanical Engineer for over 25 years and met with the team to talk through the project. In explaining the problem and desired solution to him, Mr. Ziebart’s initial idea was to make a kind of balloon of tough material that was encased in a wooden or metal box frame. This idea would not be difficult to attain and effect, however, stacking multiple units on top of and alongside many others would be problematic as the enjoining sides are not flat.
DESIGN
With the aid of the Liberty University Machine Shop contained within the School of Engineering and Computer Sciences department, ECHU was assembled. The PVC was cut using the Universal Laser System PLS.45. The roll of spandex-nylon was cut using basic scissors with fabric tracing paper as a guide to make sure all pieces were of equivalent sizes and dimensions according to the section of ECHU that the pieces corresponded. Once cut, actual assembly was done on a covered table to prevent accidental adhesion of components to the table surface.
PROCEDURE OF EXPERIMENT
In order to determine whether or not ECHU would be a successful solution to the established problem, an experiment was designed to test ECHU. One of the team members, Joby Anthony III, wore the pack for 48 hours as his normal school bag, carrying an average amount of student’s materials to test if the backpack would handle carrying a small volume of items without structural decay. After doing so, it was decided that the maximum volume that the backpack should be calculated.
RESULTS
During the initial test itself, the weight of the objects did not stretch the elastic cloth over the two days, so initial indications are that it is able to operate fully functionally as a container when not holding enough objects to force the pack to expand.
With regards to the volume of the of the backpack, it’s volume at rest was found to be .87 cubic feet, but when it expanded, it had a volume of 1.72 cubic feet. This is just short of doubling the volume, rendering the experiment a success. But, not all of the results were positive. Shortly after reaching maximum expansion, the layered panels of the backpack began to separate due to the adhesive not being strong enough.
CONCLUSION
In conclusion, the experiment, on the whole, was a success. The backpack showed that it was able to reach a maximum expansion of nearly double its original volume. The purpose of the experiment was to prove that it was possible to create a box that used elastic materials to expand, while still retaining the characteristics of a solid container, and the study proved that.
The box held the key characteristics of its shape, rigidity and the ability to balance and stand up straight while still protecting the objects from basic harm, while also expanding to almost double its volume, Going forward into the next stages of research regarding this specific project, the next questions that need to be addressed are as follows:
- A stronger adhesion method needs to be found that will be able to sustainably hold the containers together.
- A method of waterproofing the container needs to be found if the methods described in this study are to ever be applied to larger container. This included filling the gaps that form as the fabric reshapes its surface area when expanding.
- Once these first two questions are answered, a method of mass production for products made through this method needs to be devised for this research to have any viable impact. A device cannot be practical and helpful if it cannot be produced.
Overall, the experiment was extremely successful and is a good, if very small, step towards solving a lesser-talked about issue when it comes to overpopulation. If the three questions laid out above are solved in an adequate manner, then elastic materials will be extremely viable in the use of expandable containment units.
Source: Liberty University
Authors: Andrew J. Eisenman | Joby Anthony III | David Satagaj