Bridge Tester Automation

Group 5: Diego Dominguez Gonzalez, Francisco Rodriguez, Ricardo Cuellar, Xavier Davila

WELCOME!

Thank you for visiting the website for Team 5, "The FAs", consisting of Ricardo Cuellar, Xavier Davila, Francisco Rodriguez, and Diego Dominguez Gonzalez! We are pleased to have you here. This site is a way to look at the progress that our team had in creating our project for automating bridge testing. In creating this automated bridge tester, our team was able to give back to UTRGV and prepare new engineering students going through the engineering program. Please feel free to go through the website and check out what it took to create our product!

Getting to Know The Team

This picture was taken when departing from Saline, MI. where all four group members interned during Fall 2022.

From left to right: Ricardo Cuellar, Xavier Davila, Diego Dominguez Gonzalez, and Francisco Rodriguez

From left to right: Diego Dominguez Gonzalez, Xavier Davila, Francisco Rodriguez, Ricardo Cuellar

Our Aim for This Project

Professors at UTRGV aim to give the best education to their students with the school of Mechanical Engineering being no exception. In the Introduction to Mechanical Engineering course, students are tasked with creating a popsicle stick bridge that will compete to see how much weight it can withstand. Although this activity is engaging, UTRGV professors wanted something more engaging with material presented in class and a way to blend theory with hands-on learning. This is where Team 5 stepped in. We created a product that not only was more engaging with students regarding class material but a new, safer way to test bridge designs by including photoelasticity stress visualization and stress - strain plotting.

Background Information

What is Photoelasticity?
- Photoelasticity is a non-destructive stress analyzing tool that is very visual.
- Property of transparent, isotropic, birefringent, and elastic [1]

What is a Stress - Strain plot?
- It is a plot of the Force per unit area vs. the elongation percentage of the material [2]
- This gives engineers an understanding of how stiff a material is and how much energy it can take

Why is this important?

For us, this project is important and special because it is for the new generation of engineers coming through UTRGV. With this project, our product can inspire more after us to create and proud to become an engineer. UTRGV can bring more local schools to visit and bring more recognition to our great school.

Our Solution

Our solution first began by considering all design solution options available for each sub-function and making them into 12 concept variants. Pictured below are 6 of the concept variants produced. Each uses different solutions for how to pull on the bridges, frame materials, bridge clamping methods, and powering the system.

Prototyping

Concept Variant 1

Concept Variant 2

Concept Variant 3

Concept Variant 4

Concept Variant 5

Concept Variant 6

After consideration of price, weight, max pulling force, safety, and maintenance aspects of the project, the team narrowed down the design to the three variants shown below.

First Prototypes Come Life

Currently our "Office Depot" prototype stands as the only fully completed prototype. It tested variable load pattern of the proposed bridge testing system as a proof of concept. Future prototyping is in the works, but yet to be completed.

Step-by-step the team approaches the final iteration.

Prototyping Continued to Determine our Pulling Mechanism

Linear actuator replica

Successful test and final pick.

Linear actuator it is!

Pulling screw - First iteration

Failed when trying to pull specimen

Pulling screw - First iteration

Successful test but not our final pick

Concept Variant #12

Concept Variant #8

Concept Variant #5

Final Concept

Our final concept incorporates the following solutions:

Aluminum Extrusion Frame
Linear Actuator
Plastic Encasing
Arduino Controller
Vice Grip Clamps
Wall Power

Prototype Progression

With time, each prototype became more and more advanced.

Each time resembling more the final product.

A multitude of parts had to be designed and prototyped.

Manufacturing

Creating Bridges!

Part of this project includes creating the student challenge that will be assigned in class. As preparation for this, the team assembled and tested a CNC to cut polycarbonate!

A Lot of Progress with CNC Router

Working on setting up the CNC router. Pictured: Diego on the left and Ricardo on the right

Safety Is Our Top Priority

One Step at a Time!

Before cutting polycarbonate, we had to do some testing to ensure our safety!

A little messy but it gets the job done

Removing large amounts of material can be complicated but the team gets it done!

Failures are part of our progress

Some of our first iterations of a 12 in bridge were stopped due to some unforeseen issues.

From unexpected challenges, come unexpected learnings.

Team 5 had the awesome opportunity to use the first water jet in the university! The team used this complex machine to manufacture two polycarbonate panels that will keep the bridges from deforming out of plane.

Creating the Final Product!

Some custom-made parts needed to be machined.

Bridge Clamping Mechanism

Ricky had to be very precise while machining the bridge clampers. He did not have much room for error but got it done, nonetheless.

Bridge Fixtures

With some right angles, tapped holes and complex geometries, Diego spent many hours in the machine shop creating two Bridge Clampers

Load Cell Coupler

Ricky put his lathe machining skills to the test by creating this complex coupler that was able to connect the linear actuator to the load cell.

Others, had to be 3D Printed!

Electronics Encasing

Xavier had to come up with an ingenious idea to hide the wire mess and make the final product look nice and clean.

Lamp Holder

Ricky proved to himself that he was a pro at both machining and 3D printing by designing the lamp holders.

Linear Actuator Holder

Diego also had to do some 3D printing of his own. Otherwise, the linear actuator would keep falling after each test was done.

Testing and Simulations

Testing time!

Placing a 12mm x 5mm polycarbonate as a simply supported beam, we tested the piece with weights available

Before cutting polycarbonate, we had to do some testing to ensure our safety!

Testing Polycarbonate bridges!

With This!

More and more testing was performed using our lovely "junkyard" prototype

Testing with advanced prototypes!

As our prototypes became more complex, so did our testing!

Finite Element Analysis Time!

We used finite element analysis (FEA) to determine what bridges to test. Simulating bridges breaking gave us the ability to quickly analyze the performance and behavior of bridges without the need for physical prototypes, saving time and resources in the design and testing process.

Furthermore, this gives us the ability to give constraints to students designing bridges to be test on the prototype.

Electronics

But one questions remains, how does it all work???

"At the push of a button"

Team 5 wanted to ensure that the whole device would be simple to use. Therefore, the team uses a monitor that allows the user to control the linear actuator and read load cell values all on the screen.

While the team manufactured the frame and trusses, Franky worked on the coding and hardware for this project.

Here on the left is the "living heart" of our design. It consists of:

Power Supply
Arduino Mega2560
DC to DC Buck Converters (X2)
Omega Load Cell with HX711 Board Connections
Firgelli Linear Actuator
BTS7960 43A Motor Driver
NEXTION Display

The traditional screen that we avoided...

LCD for arduino is a staple for DIY projects. This module is capable of delivering messages from the Arduino but is not capable of delivering messages back to Arduino. Furthermore, the LCD is small but requires many pins to use.

The screen that does it all!

Team 5 decided that the NEXTION display had much more potential compared to other screens. It's customizable in terms of layout, can read and send Arduino commands, and only requires two pins for power and two pins for communication. The image above is rough draft of the final screen code. Here we can see the Arduino sending data into LBs section, but also touch screen buttons that allow us to control our Linear Actuator.

Prep-work

The NEXTION software allows for customization on how data is presented.

Here is the first breadboard prototype of all the components connected to each other.

Buck converters were adjusted for components in order to prevent damage.

A kill switch was also implemented into the design in need of an emergency shutoff.

Code

On top of regular commands for the Arduino, there are special commands that are necessary in order to maximize the most of the NEXTION screen. The syntax may be scary at a first glance, but with proper documentation and comments, the code becomes a lot easier to understand.

The goal of these comments is to help anyone who wishes to modify or replicate our project. Thanks to numerous libraries that are available to download, the code is relatively straight forward.

Some of these snippets of the code are just examples of how the NEXTION syntax works with the Arduino.

Test, Test, Test!

Multiple tests were done in order to proceed with the hardware. Linear actuator and screen were tested separately first before being connected together. The last test was connecting the two systems for a bridge test.

With these tests successful, it was time to solder these connections.

Linear actuator movement and Calibration Function using screen

Load Cell values on screen (learned that font was too small)

Commanding the Linear Actuator to move until certain values are read.

Where are we?

Almost done!

Team 5 is happy to share that we are on the last stages of building the final product.

We are currently waiting for some part to arrive and for others to be 3D printed.

With our senior year coming to an end, we approach the bittersweet end of our college careers but at the same time, we are excited to see this project 100% done and to move on to a different stage in our lives.

Last Push!

References

Page updated

Google Sites

Report abuse