Our group is working on making an adaptive bed for a child with level 3 autism. The family has asked us to make a design like that of the “Cubby Bed.” A cubby bed is a bed made specifically for children with autism to ensure safety whilst sleeping. The hope of our project is to keep the child in his bed during the night to ease his mother’s worries about him wandering and getting hurt. She has also asked that we build the bed to fit a twin-size mattress with high durability, as the child is incredibly strong for his age.
Qualitative Specifications
Quantitative Specifications
Cubby Bed
Noah bed
Amazon Cubby Bed
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Properties:
Components:
Properties:
Components:
Properties:
Upon further research, group 5 has determined it best to create a product that is a mesh between concept one and three. The wooden frame of concept three allows for better fabrication whilst the idea of a mesh/fabric lining around the bed itself from concept 3 ensures safety. This concept design was created with the family in mind, including a motion sensor to alert the family should the child begin wander around at night despite the precautions.
Our group had the fortunate opportunity of meeting with the family in person to get a proper idea of what they wanted. After a good brainstorming session, our team came up with our final design. Our final design encompasses concept design one and two, creating a fleshed out project.
The main goal of the adaptive bed is to create a safe environment for the child that provides a nice place to sleep whilst reducing the parent’s worry of the child wandering at night and possibly getting hurt.
Our bed does this by improving upon a metal twin bedframe. We decided to reinforce it with wood and wrap a tear resistant fabric around each of the posts. On one side of the bed there will be the trampoline mesh, allowing for the child to still see out into the room, creating a better environment than a fully opaque fabric. The trampoline mesh also comes with a built in zipper meant to withstand children leaning against it, calming our worries about a major weak point.
The Frame
The first thing our group did, was discuss the ground work of the adaptive bed. We decided to use a metal bed frame from amazon. Since the frame has likely been safety tested, we felt good using that as our base. Our child is also known for jumping, so a wooden base frame was not really an option, as wood cracks over time with applied force, metal at least bends first. This part of the bed creates a transfer height (ground to where the mattress bottom sits) of 12 inches as desired in earlier designs.
To make a place for the mattress to sit without sliding, we decided to use 2×6 inch wooden beams to create what could be considered a pocket for the mattress. This is screwed directly into the metal frame and wooden posts. This makes sure that not only does the mattress not shift, but our metal frame is reinforced.
Moving to the posts. We decided to use 4×4 inch wooded posts as they are sturdy and also commonly used in the design of bed frames. These posts will be about 5.5 feet in height, creating an internal height (bottom of mattress to top of bed) of 4.5 ft, the family agreed that this is plenty of space.
On top of the posts is essentially a copy and paste of frame used to create a pocket for the mattress. This is located so that the top of the 2×6 inch wooden boards are flush with the top of the posts. This allows for our waterproof fabric to be laid over later.
The Fabric
Our group decided that the best way to keep the child from wandering around at night was to use a tear resistant and water resistant tent fabric along three sides of the bed, using a trampoline mesh replacement for the front. This allows for the child to see out of the bed without as much of a risk of the mesh tearing, which was a major concern with concept design 1.
The choice of a trampoline mesh replacement was made because the zipper included is made to withstand forces leaning against it. it also comes with a buckle to make sure that the zipper does not easily give way with force at the bottom. This makes the choice a safe one for keeping a child from wandering at night.
To attach the fabric, we planned on going around the posts, essentially creating a sleeve for the post to fit into. Each side of the fabric will be stapled down, allowing for a more even distribution of force, as we are worried that if we only sewed a sleeve, it would tear at the seams.
Foam will also be attached to each post. This is being done to ensure that the child is not hurt in the middle of the night should he get up and play around in the bed. Our goal is safety and strength Afterall.
The Motion Sensor
Our family has also asked us to implement a motion sensor in case the child does get out at night. We found a motion sensor on amazon that comes in two pieces; the sensor and the alarm. The sensor will be mounted to the top of the bed so that the child does not reach it, whilst the alarm will be plugged into an outlet in the parent’s room. This allows for the parents to know without waking up the rest of the family.
Quantitative Breakdown
4in x 4in x 6ft wooden posts X 4
2in x 6in x 14 ft wooden beams X 4
2in x 6in x 8 ft wooden beam X 4
Twin Bed metal frame X 1
Motion Sensor X 1
By yard – Kelly green waterproof fabric X 10
By 15 ft diameter Trampoline Mesh X 1
The goal of this analysis was to analyze the force necessary to crush one of the four wooden posts of the bed. This analysis was done because we were informed by the family that the child has a tendency to climb atop structures. We hope that he will be unable to climb the bed due to our design, but in preparation an analysis was done anyways.
The first part of the analysis was determine what the slenderness ratio of the column was. Due to our determined value, we recognized the column was considered intermediate. This is crucial because it means we cannot simply use the Euler formula for buckling.
Using the intermediate/Johnson column equation (adapted to a square cross-sectional area), we were able to solve for the critical load.
From this analysis we have determined that even if the child were to get atop the structure, we do not have to worry about the column failing, as it can withstand over 90,000 psi of downwards axial force.
Continuing the analysis of one of the four wooden posts of the bed, we decided that an analysis of the deflection with force hitting the side of the column was crucial. We do not want the structure to fail should the child apply a force to the post from inside the adaptive bed.
To account for any movement in the bed, we have labeled the beam as fixed-free for this case.
The analysis starts with finding the moment of inertia, a crucial portion of beam deflection analysis.
From there the deflection was calculated in variable form, allowing us to analyze the deflection with almost any applied force.
The final analysis was of the frame of the bed itself. Since the frame is going to be under a near constant force, the child sleeping on it, it needs to be structurally sound. This piece is also crucial because the rest of the frame is centered around the metal support.
Several assumptions were made during this analysis, particularly the dimensions of the slats and the cross sectional area. We decided on a hollow tube as, in our group’s experience, that has been what most bed frame’s are fabricated as.
Although there is an expected weight of 35 lbs, we decided to analyze at a much higher stress. Assuming the slats can be analyzed as fixed-fixed beams, we determined that even under a severe deflection, the stress is minimal. Upon further analysis, a weight of 35 lbs would cause practically no visible deflection. This means that the chosen frame is suitable for the project.
The fabrication process began with constructing the metal frame, as it served as the foundation for all other components. Next, the wood was cut and sanded to match the dimensions of the metal frame. Once prepared, holes were pre-drilled through the wooden posts and beams to ensure accurate and secure assembly. Six-inch screws were selected for safety and strength, with three screws used for the long beams and two for the short beams. After assembling the wooden frame, an additional round of sanding was completed to improve the finish before painting. The wood was then painted with two coats to achieve a consistent and defined color. Once dry, the trampoline mesh was initially stapled to the long beam only to allow for easier transport. Foam padding was epoxied onto the wooden posts and further secured using zip ties. For transport, the long beams were removed while the short beams remained attached to the posts. Upon arrival, the bed was reassembled. Trampoline mesh was added around the foam to hold it in place and prevent the child from accessing the foam. Then more mesh was fully stapled in place to cover the side of the bed. Fabric was then installed across the head, top, and foot of the bed, while the wall-facing side was left open to allow easy access for changing sheets. Finally, glow-in-the-dark stars were added to cover the exterior staples.
To ensure the bed frame, fabric, and trampoline mesh were secure, a series of tests were performed. While the wooden frame was bare, loads were applied by jumping onto it and hanging from it to verify that it could support weight without noticeable movement; the frame remained stable. Additionally, the mesh and fabric were pushed outward from the inside to evaluate their extension and to confirm that the staples remained secure. The fabric was also pulled to assess its resistance to tearing, and no damage was observed.
To ensure the child remains safely in the bed, make sure the alarm is turned on. Always fully close the zipper and verify that all clips are securely in place. Regularly inspect the padding, mesh, and fabric for any tears, and check for loose screws. If any damage is found, replace the affected materials promptly. Ensure the bed remains flush against the wall, and only move it for cleaning when the child is not inside. Do not allow climbing on the exterior of the bed frame.
This project provided a real perspective on what it means to be an engineer. We were given a problem, and it was up to the team to determine how to address it. Multiple beds were created, each designed for a different child with unique challenges, showing that a “one-size-fits-all” approach does not work. Each child required different features based on their individual needs. Seeing such diverse designs highlighted the importance of teamwork in engineering. Each member contributed unique ideas, which were combined into one final design, while other teams developed their own solutions as well. This project also demonstrated the value of collaboration. Although we faced challenges during fabrication, especially the requirement that the bed be disassembled within the next few months, we were able to overcome them as a team. Overall, this experience allowed us to think like engineers and apply our skills to support families in need.
