Stress Analysis Design Review Website

Russell Kirmayer, Alex King, Ben Avery

Spring 2013

Crane Image 1

When designing our crane, our group set out to design the most sturdy sturcture possible. As seen in the images, we tried and successfully achieved this by building a large, well stabilized, and sturdy structure that was very rigid. When lifting the weight, this allowed the arm to transmit as much torque as possible to the weight, and allowed us to lift the weight 4 inches. We predicted that if we could build as stable a structure as possible, that our performance would be based on the ability of the servo to lift the weight. Thus, our crane performed as we predicted

Crane Image 2


While our crane was overweight by a few ounces, we are proud that it was able to lift the weight a little over 4 inches. This was achieved by having a well designed arm attached to the servo that allowed the weight to rotate in a socket in the arm as it was lifted, reducing any unnecessary forces or friction.

Servo Analysis:

The length of our servo arm was 4 inches from the point of rotation on the servo to where the arm contacted the weight. The weight of the mass was 2 pounds. The maximum output torque of the servo of 96 oz-in. The maximum torque used by our servo was 73.9 oz-in, which is 76.9% of the maximum torque available. Since our arm was 4 inches and the weight was lifted 4 inches, the arm rotated on a range of 45 degrees.

Other comments/images:

Additionally, we are proud of how well our crane was built. The crane was very rigid and hardly bent, a feat that took a lot of time to build and add cross braces to.

Below are images from while we were building the crane. The less complete one was our first attempt at building the base of the crane before we learned to fold the strips of metal in half to add rigidity. Crane Image 3 Crane Image 4