The Great Team1 Week 8 : Engineering Analysis Bunk Bed Converter Adam Brown Blaine Gardner Sarah Gleaton Jimmy Jiang Addisu Lemlem Lee Tschaepe 7/12/2006

The Great Team2 Locking Mechanism

The Great Team3 Locking Mechanism

The Great Team4 Pin Analysis

The Great Team5 Bed Positions Up Position- 0 degrees rotation Down Position- 90 degrees rotation

The Great Team6 Free Body Diagram Force from mattress and mattress frame Force due to weight of arm Torque to be generated by spring *Maximum Torque is required in the vertical position

The Great Team7 Pivot Arm Arm is 2” x 2” mild steel square tubing Each arm is 41” long Each arm weighs lbs Torque 90 by each arm= T= F(lbs) x L/2(in) => x 41/2= lb-in

The Great Team8 Frame and Mattress Frame weighs 25 lbs Mattress weighs 50 lbs This force is distributed over 4 arms; each arm must support ¼ of this force.

The Great Team9 Calculations -Torque due to mattress and frame: (50/4)*41+(25/4)*41= Torque due to weight of Pivot Arm: *(41/2)= lb-in Total Torque generated for one arm: lb-in

The Great Team10 Results If a torque of 850 lb-in is applied using a torsion spring, the user must lift 3.47 lbs per arm Total user required force to upper bunk assembly is lbs

The Great Team11 Bed Frame Analysis

Secondary Moment of Inertia c = center of mass = 0.85 in

Frame Analysis – Long Side Bending Stress Long Side of Bed FrameMaximum Bending Stress Material: Carbon Steel 1040 CR, Yield Strength = 71kpsi

Frame Analysis – Short Side Bending Stress Short Side of Bed FrameMaximum Bending Stress Material: Carbon Steel 1040 CR, Yield Strength = 71kpsi

Frame Analysis – Bearing Stress LONG SIDESHORT SIDE Bolt: D = 1/4”, Carbon Steel 1010 CR, Yield Strength = 44 kpsi

Frame Analysis – Shear Stress LONG SIDESHORT SIDE Bolt: D = 1/4”, Carbon Steel 1010 CR, Yield Strength = 44 kpsi