Document Type

Undergraduate Project

Date of Degree Completion

Spring 2024

Degree Name

Bachelor of Science

Department

Engineering Technology

Committee Chair

Charles Pringle, PE

Second Committee Member

Dr. John Choi

Abstract

This report describes the design, construction, and testing of a small-scale articulating balsa wood bridge that allowed passage over normally impassable terrain. The bridge was required to span a 400mm gap, while also articulating the midpoint of the bridge 140mm above its resting position. The bridge also needed to support a 20kg (44 lbs.) point load in the center of the bridge, and the bridge and articulation tower together needed to weigh less than 85 (0.19 lbs.) grams.

To construct the bridge, statics and mechanics of materials was used to design a truss that was calculated to support the load with a safety factor of 1.25. An articulation tower was constructed, and string was attached from the bridge to a motor that allowed the bridge to be raised. A switch on the motor allowed the motor to articulate the bridge up and down. All bridge and tower members were constructed using balsa wood and wood glue. The parts were manufactured by measuring and cutting stock balsa wood to length.

Once constructed, the final weight of the bridge was 79.5 grams and spanned 429mm in length. The bridge was able to hold 634.01 N (64.7 kg) before failure. Under a 19.4 kg load none of the truss members experienced fracture. The bridge articulated 155 mm above its resting position and articulated to its max height in 0.97 seconds.

Download

Share

COinS