Language

English (en)

Publication Date

Fall 2025

Document Type

Final Report

Embargo Date

12-8-2025

Problem Statement

This report discusses the design, development, and testing of a parachute snatch force tester for MEMS 411 Senior Design. The device is for the WURocketry Team, and aims to measure the peak force exerted on the rocket bulkhead during parachute ejection. This peak force is known as the snatch force, and is incredibly important when it comes to maintaining safety, improving performance, and material selection during the rocket’s production process. Current methods for testing and recording this snatch force are limited, so our team aimed to create a simple and cost effective solution. Our design utilizes a vertical support that stores elastic energy in a bungee cord. When released, the stored energy launches the bulkhead downward until the attached shock cord fully tightens. The shock cord is attached to a load cell which is connected to an HX711 amplifier. The load cell then measures the peak force at the moment the shock cord experiences full tension. Three performance goals were set at the beginning of this project. The first was to measure bulkhead acceleration values within 5% of flight data. This goal could not be fully met due to a malfunction with our accelerometer. The second goal was to measure force values within 10% of calculated values from models. While we were able to obtain consistent force values from trial to trial, they were not within 10% of the calculated values. The final goal was to have the device operate 10 times in a row with less than 5 minutes between each trial. This goal was successfully met, and there were no concerns when running the device through multiple trials.

Author's School

McKelvey School of Engineering

Author's Department

Mechanical Engineering and Materials Science

Class Name

Mechanical Engineering Design Project (MEMS 411)

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