Roll Hoop Research

Design Philosophy (Solar and FSAE Teams)

The safety of the driver is the number one priority when resigning the roll cage as it is the layer of defense between the driver and everything around them. So, when designing a roll cage, the safety of the driver must be the primary consideration, and following the regulations is a must. The movement of the occupant is a good place to start when considering the shape of the roll cage as it outlines the area in which one cannot place tubes, therefore being able to work around such a cell gives direction and a base idea.

Essentially, the design must be strong enough to withstand the potential loads that would be applied to the roll cage while eliminating excess weight therefore using less materials and a cheaper cost. Additionally, being able to reduce the height of the roll cage would not only decrease weight but also reduce toppling given that the roll cage would have a lower center of gravity. All things considered, safety and reliability are the most important considerations when designing the roll cage.

When complying with the regulations, the most important part is ensuring the safety of the driver and implementing certain considerations with respect to this goal. More often than not, the regulations regarding the roll cage come with the tubes concerning the person, and their movement. It is very important to design the roll cage concerning the movement of the driver, and more importantly where their body would move if the car were to crash or tip over. Lastly, it is important to understand where the load cases are applied and where to place cross bracing to prevent deformation, and pay close attention to points of stress concentration and understand where stress flows and how to manage it.

Given all of the regulations regarding the roll cage and occupant cell, this seems to be the only concrete measurement given when considering the space between the driver and the roll cage. In my current model, I have allotted more clearance than the 50mm given that padding is not included in the design to further ensure that this regulation is met.

Additionally to the clearance, there are the load cases that must pass, and more importantly the occupant cell cannot deform more than 25mm.

Combined Loading: Simulates the roll hoop’s ability to handle impact scenarios that involve multiple force directions simultaneously.
Sideways Angled Loading 30 degrees: Simulates a shallower side angle impact, if the roll hoop were to get struck from the side.
Sideways Angled Loading 60 degrees: Simulates a steeper side angle impact, similar to a scenario where the car might tip over and hit the ground.
Sideways Horizontal Loading: Simulates the upper part of the hoop being struck during impact or rollover.
Rearward Horizontal Loading: Simulates a force from the back of the car towards the inner part of the front hoop.

Roll Hoop Designs	Observations	Visual Representation of Load Cases	Ease of Egress

I am a bit skeptical about the car regarding the regulations for backwards force on the front or back of the hoop as there is no bar across the top to prevent deformation.
In terms of cross bracing, there seems to be a good amount to secure the driver in case of anything, but keeping weight in mind.
I think that the best part is the ease egress although this might cause bracing problems.

In this case, egress could honestly be either upwards or forwards. Ideally, one would have to get out of the car upwards because that would allow them to avoid any interaction with the front of the car where another systems are housed. Due to the lack of a tube on the top, I believe that this is the intension, with the cross braces doubling as a jump off point when stood up in the car.

This is a rather tall roll hoop which gives Increased headroom to enhance driver safety during rollovers but adds both weight and high center of gravity.
Ease of egress seems to be harder than the SC6 due to having to crawl through the front traingle, which could delay exit time, as this shape is more pyramidal than anything.

Ease of egress seems to be harder than the SC6 due to having to crawl through the front traingle, which could delay exit time, as this shape is more pyramidal than anything. There is something to be said about this shape and how it may benefit the stress concentration point as it is all at the top, and therefore there is no bracing bar at the top.