Blowing up bottles: the procedure

First thing to be tested is the performance of the PET bottles. The procedure of this experiment was defined with the guidance of Dr.Ir. F.A.Veer, Associate Professor of Materials Science in the Faculty of Architecture, TU Delft.

Thus, the experiment can be organised in the following series of steps:

1. Define the dosage of dry ice the PET bottle can support
a. Start with extreme dosages to determine the maximum amount of dry ice the bottle can support 

b. Lower dosage to observe the reaction of the bottle and the form it takes 

    when subjected to different amounts of pressure (if the bottle curves extensively it will 

    cooperate less with its adjacent bottles)

Step 1

2. Test various types of bottles in terms of shape

a. Bottles of rectangular section will probably cooperate better than those with a circular 

b. Bottles' elevation, again in terms of contact surface between the bottles

1. Step 2

3. Check leakage and therefore for how long will the bottles be stable

a. Add dry ice in the bottles and close them normally. 

    Measure daily for a week’s period the diameter of the bottles to estimate possible leakage 

b. Heat-seal the bottles and repeat the experiment

Step 3

 

4. Test the bottles in compression (different types of bottles and different dosages)

Step 4

 5. Place a number bottles together and test them under lateral compression 

Step 5

Prototyping and testing: series of steps and questions to be answered

To investigate the behavior of the floating module, a series of prototypes will be produced and tested in compression. First step is to identify the properties of the core and work towards its optimization in terms of strength and lightness. Once satisfactory results are reached, the optimized core will be laminated with a layer of FRP and, consequently, the properties of the composite module will be defined, through compression tests.

More specifically, the research will be organized as following:

By this stage the questions that need to be answered are summarized as such:

 Core

          

              PET bottles:

o      Grams of dry ice needed

o      Compressive strength of the carbonated bottled containing the dry ice

o      Packing method (vacuum membrane, band, adhesive?)

o      Should the void space between the bottles be filled?

o      Relation/Connection with the FRP layer

              PET Foam:

o      Is the lowest-density version of this foam material (80kg/m³) suitable?

o      Relationship with the exterior FRP layer (needs protection? Infusion holes in foam?)

o      Relationship with the bottles’ caps- should a sheet layer be placed in between?

Then the second phase contains the core with the surrounding FRP layer:

 Issues to be determined by this stage:

FRP layer

            Resin:

o      Resin to be used (in terms of strength, sustainability-recycling, durability)

o      Total thickness of the material

o      Volume shrinkage? Absorption from

             Fiber reinforcement:

o      Fiber reinforcement to be used  (in terms of strength, sustainability-recycling)

o      Type of fabric

o      Volume percentage of reinforcement

o      Direction of reinforcement

             Gelcoat:

o      Is it necessary?

o      If so, what kind of gelcoating should be applied

Floating Component

o      Compressive and bending strength

o      Total mass. How can the optimum strength-mass ratio be achieved?

o      How is the highest part (more foam) behaving in comparison with the lowest

When the stage of prototyping and testing is over, digital simulations will be required, to further understand the behavior of the platform as a whole:

Both for the physical tests and the digital simulations a list of criteria will be made, for the assessment of the different alternatives.

Issues for investigation

At this stage of the design, a composite floating module is developed based on a series of assumptions that have to be clarified in order to guarantee for its efficiency. The designed composite material (GFRP+PET foam+PET bottles) needs to be tested through the production of 1:1 physical prototypes in terms of strength and stiffness. The performance of the module needs to be evaluated and consequently optimized, according to the results of the tests. Once the consistency of the composite structure is precisely defined and its structural properties and behavior are known, simulations have to be done using computational tools, to understand the performance of the floating platform as a whole. 

Alongside the above mentioned research, it is important to investigate the possibility of switching from non-recyclable GPR polyester to indefinitely recyclable self reinforced PET resin, to form the shell of the floating modules. The ability of this thermoplastic composite material to perform structurally needs to be verified.

Starting with the prototype making, first, 3 study cases will be explored and compared on basis of their performance.  According to the results, the next steps of the experiment will be defined. 

Case 1

Case 2

Case 3