Engineering Education Expansion Pack

Project OVerview:

This project, sponsored by UC San Diego engineering professor Huihui Qi, aims to develop a set of demonstration tools and design challenges to supplement the undergraduate engineering curriculum. The educational kit will provide multi-functional visual aids to be used by professors and students that encompass several different topics from two core undergraduate engineering courses, Kinematics and Solid Mechanics. This work addresses gaps in long-established, traditional methods of engineering instruction by providing physical renderings of fundamental concepts. Students are able to get a tangible sense of principles ordinarily introduced in the form of images and written assignments, which will engage more learning styles and reach those for whom other methods of instruction have otherwise fallen short. Each product produced in this kit has gone through rigorous inspection and prototype iterations to ensure that they are in alignment with our most fundamental goal of presenting a difficult concept in an understandable manner. This project team has collected survey data from undergraduate engineering students at UC San Diego to determine which concepts are most difficult to understand, and in response, designed eight demonstration tools and two design challenges that address each concept .

*All demonstration tools and design challenges

are described below and on the Final Design subpages. *

Statement of Requirements:

Educational pack tools, demonstrations, and design challenges should:

Be used for visualization of engineering concepts
Cater to different learning styles
Convey information efficiently
Be produced at low cost
Be easily operable
Include a compatible calculation activity
Have multi-functional features

DEmonstration Tools:

2d Moment About a Point

A rigid body made out of acrylic is pinned into a peg board at a pivot point. Strings are tied to the body and hang from rods that can be placed at any point in the peg board. A bag of nuts (mass) hangs from the string to create a force on the body. The professor can provide the dimensions and one of the mass values so that the student is able to solve for the second mass needed to keep the system in equilibrium, which can then be checked through the demonstration.

Originally Proposed Design

Actual Walkway Constructed

(Cause of Failure)

Hyatt Regency WAlkway Models

A real-life example to showcase why engineering fundamentals matter is the Hyatt Regency walkway collapse of 1981, which could have been avoided if simple statics principles were observed. Two models were built that demonstrate the primary cause of the walkway failure. The left image shows the hotel’s originally proposed design, in which the blue bars represent the two suspended walkways in the hotel. The original design called for a single pair of hanger rods, which would pass through the fourth floor walkway to the second floor below. In this setup, the load of the two walkways is independently transferred to the hanger rods. The instructor will be able to lift the top bar without affecting the other. The right image models a design change that was ultimately built in the hotel. In this configuration, the entire weight of the second floor walkway is being supported not directly by the hanger rod, but by the fourth floor walkway above. Students will notice how when the instructor lifts the upper walkway, the lower walkway moves too. The hanger rods are still carrying the same load at the top, but the two nuts on the upper floor are now supporting the weight of both walkways. This seemingly small design change effectively doubled the load on the bolted connections and led to the collapse of the walkways.

3D Moment About a Point

The model was built to showcase a physical rendering of a 3D moment about a point. The model consists of three interconnected pipe lengths that may be twisted, bent, rearranged, and rotated at the student or instructor’s will. The purpose of this model is to allow instructors to showcase a 3D concept in actual 3D, and to provide students with a tangible representation of a system commonly referenced in their coursework. The inspiration for this design comes directly from Vector Mechanics for Engineers: Statics, which is the textbook utilized in MAE 30A: Kinematics.

3D Moment about an axis

This model is meant to be an interactive homework assignment in which students solve for the moment about an axis. The model can be arranged in different configurations by using rubber bands of varying lengths and thicknesses at the 3 different hook attachment locations. By using a spring scale to apply the rubber bands, the student can measure the tension force. Then, the student will use a protractor to measure the resulting angle from the tension force. With the system dimensions, angle, and tension force known, the student has enough information to solve for the moment about the X axis (hinge axis) due the force applied by the rubber band.

Reactions/Moments at Supports and Connections

This model was built to demonstrate reaction forces and moments for various supports and connections. Each panel of the box contains different types of supports or connections. The purpose of this model was to allow the user to physically interact with the supports and connections often seen in textbooks or sample problems and better understand the concept of reaction forces and moments. The panels of the box have detachable hinges to allow for easy distribution in the classroom for in person learning or demonstration in the camera screen for online learning. The box is held together with the clear acrylic lid and includes a top handle for easy transport.

Acceleration

This model demonstrates the normal and tangential acceleration of a particle. The model consists of a tennis ball and rope. When swung in a circular motion, the rope creates a tension force on the ball. As a result, the ball has a normal and tangential acceleration. The purpose of this model is to allow the user to interact with and to visualize acceleration.

Buckling and Stress

This model was created to showcase geometric buckling and stress (i.e. torsion, tension, and compression). The model is made out of super cushioning polyurethane foam and the grid lines are drawn on using a paint marker. The polyurethane foam is soft and cushiony which allows for easy twisting and bending. The grid lines allow the user to visualize the deformation of an object under different forces.

Vector Decomposition box

This model will help students visualize a vector and planes in 3D space. It is required that the vector be of variable length and direction, with the ability to attach planes along its length. It must also be optimal for online instruction, meaning that size and color choice are important considerations.

Design Challenges:

Center of MAss Design Challenge

Students will be presented with 9 shapes and must calculate the center of mass for each. Next, students will design a stacked configuration of all 9 shapes based on the center of mass calculations. Then, students will build the designed tower using the physical shapes. The goal is to produce the stacked tower with the greatest height that remains stable after a given period of time. The objective of this design challenge is to foster an intuitive, physical understanding of the concept center of mass.

Truss Design Challenge

Students will design and build a truss structure as a group. They will compete against other groups and receive rankings based on a performance metric. This performance metric will factor in strength of the structure, cost of materials, and environmental impact. Each student in the group must come up with their own unique design for either a truss bridge or truss roof, which should be analyzed using the method of joints. The students will construct the bridge using the provided materials to test the strength of their bridge and the accuracy of the calculations.

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