Bottle Opener, Post 1

We began by brainstorming possible two-dimensional shapes that could function as a bottle opener. For this part of the process, we used our intuition to decide whether the design was feasible enough to complete the task of opening the bottle. We explored three general shapes and made modifications as we went to display our thought process for designing a functional and comfortable bottle opener.

Series 1: We designed this series with the intention of creating force on a single side of the bottlecap. Our first design featured a fitted hole in the middle of the material to enable the insertion of the bottlecap and the ability to tightly wedge the cap in the instrument before applying force.

We next made a modification to this design by increasing the base to shape a handle for an easier grip.

We then further modified this design by increasing the width between the hole and the outer rim of the instrument, as we wanted to reduce the possibility of the material fracturing. 

Series 2: We designed this series to apply force to two opposite sides of the bottlecap. The first idea was constructed to be in contact with the cap on the right and left, with a handle component. Its method for removing the cap would be a downward motion (applying force to either side of the cap), but it may also be used with an upward motion (placing force on the "v" of the design).

We then modified this design to have a small rounded shape in the crook of the juncture. Its purpose was to wedge under the cap and create extra leverage during the downward motion. 

We then explored the possibility of the handle being asymmetrical. A curved edge might have made the grip easier, but we worried about the sharpness of the angles.

Another development on this series that we explored was the addition of two smaller protrusions similar to the one in the middle on each "arm" of the design. We then encountered the challenge of fitting the bottlecap into the area as a result.

Series 3: The evolution of this series aimed to apply a force on the edge and center of the bottlecap. We began with a simple rectangular design that applied force to the underside of the outer edge of the bottlecap which aimed to remove it by a downward motion.

We then explored the possibility of asymmetry in the handle.

We further modified the series by returning to a symmetrical, rounded handle. We then decided to explore the benefits of placing a pointed component at the center of mass of the bottlecap. We hypothesized that the addition of such a component would increase the leverage of the opener.

 We ultimately decided upon the final design of series 3. It featured a curved handle and the sharp protrusion aimed to rest at the center of mass of the bottle cap.

This design showed showed promise because it appeared to be aesthetically pleasing and able to be modified in regard to ergonomics. 

Physics - Cantilevers and Deflection

This design seemed like the most feasible option with the consideration of physics, especially in its function as a cantilever. We began to consider physics in the design process. Force was intended to be applied at the top of the design, and the addition of the point aimed at the center of the bottle cap was to supply further leverage. The examination of the materials available to us resulted in further analysis of the integrity of our design. We considered force, length, Young's modulus for the material, and moment of inertia. We combined these variables to predict deflection. Our first aim in analyzing our design was to reduce its deflection upon applying force to the bottle cap. As a smaller deflection would result from greater stiffness and practically yield better results, we considered the individual variables themselves. 

We began by looking at length, a controllable variable. We had a length limit, but we also wanted our opener to fit comfortably in a hand. This resulted in a handle that was only as long as it needed to be. A longer handle would have decreased the overall deflection, as force might have been applied to a distance further from the point of contact with the cap. As length is cubed and in the numerator of the deflection equation, a longer length would have increased deflection.

We then considered force, which we were able to influence as well. We considered torque as we designed our prototype through the addition of a handle. Less force is required if applied at the end of a length than in the middle, and a longer length required less force than a shorter length. 

Young's modulus, E, or "stress over strain," was predetermined by the material available to us. Delrin has a specific tolerance and material stiffness. 

We were able to influence the area moment of inertia "I." As it is the stiffness of the cross sectional area of a material, we were able to influence it by selecting a specific thickness of Delrin (having been provided with 3 options). 

Using the deflection equation: At length L, deflection = (FL^3)/(3EI)

We could not control the constant 3, nor Young's modulus. However, we were able to control F, L, and I. For minimal deflection, we would want to minimize force, minimize length, and maximize the area moment of inertia. However, this in practice was not feasible. We did not select the thickest sheet of Delrin, as it would have been impossible to wedge underneath the bottle cap. Such tradeoffs were then considered. We picked a thinner sheet of Delrin and increased the length of the handle to reduce the amount of force required. This increased the degree of deflection, but seemed to balance our design with the materials available.