P19037: Skreppa Modular Shoe
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Systems Design

Table of Contents

Team Vision for System-Level Design Phase

Phase Team Plan

Our team plans to learn more about what concepts we are going to ultimately select by developing multiple different solutions for developing a modular shoe. From these multiple different solutions, we aim to find several solutions that could work for joining methods, topsole, and outsole that we are going to use to design and fabricate our modular shoe. Additionally, the team is hoping to refresh skills and learning from previous coursework to apply our learning to this specific use case.

Phase Team Outcome

During this phase, our team was able to quantify what factors we want in the shoe, in addition to various other factors in the Skreppa Design. At the beginning of the phase, we decided to benchmark against other existing shoes on the market, specifically hiking boots, running shoes, and everyday walking shoes. After careful analysis of a Morphological Chart, we were able to step into the concept development aspect of Systems Design. Throughout this phase, team members sought council from previous professors with expertise in material and material processing fields. After gathering data, evaluating risks, concept designs, and analysis of said designs, our team completed the Systems Level Design Phase on the right foot. As an added benefit, the Skreppa Team has also decided on an official name to the overall shoe - The Delta.

Functional Decomposition

Purpose

Below is our existing Functional Decomposition - of which we used the Functional Tree Method. Each of these functions and subfunctions are based on the Customer & Engineering Requirements tables completed in the previous phase. This chart allows us to hone in on what will be structurally important to be delivered during the final design of the shoe. With this tree being completed, it allows us to start concept designs based off of what each function represents.

Functions & Resulting Subfunctions

Functional Decomposition

Functional Decomposition

Inputs and Source

  1. Template & Example
  2. Project Objectives
  3. Engineering Requirements
  4. Benchmarking Data

Benchmarking

At the conclusion of this project, we want a shoe that can fit multiple uses for the average person. Ultimately, we want to reduce in-house clutter, in-landfill waste, and everyday hassle of changing shoes for what the customer is doing. To start this off, we want to compare the current market options to decide what we want to focus on and what to keep in mind. There are a few modular shoes available so we took a look at the companies that are still in production, in addition to big-box shoe companies. Benchmarking allows us to hone in on what would make the best possible solution. We decided to weigh in on the following qualities: the number of tops and bottoms, manufacturability, cost, market reached, locking mechanism, weight, comfort, aesthetic, durability, and average reviews.

Benchmarking

Benchmarking

Inputs and Source

  1. PRP
  2. Engineers for a Sustainable World - RIT Chapter
  3. Companies Benchmarked: Shooz, Mime et Moi, Onesole, Merrell, KI, New Balance, Vans

Concept Development

During the concept development phase of systems level design, we referred to our previous work to gather concept ideas. Since our project is relatively unique, in the fact that each concept could be drawn as a whole new shoe. Before going to the drawing board, we first looked at our Functional Decomposition Tree. The team weighed in what was the most important for our overall shoe and things to consider while designing. From here, we generated our Morphological Chart. From this, each team member individually selected characteristics that they found either probable or an interesting concept. The table of the team’s selections is below:

Design Ideas

Design Ideas

From this Morphological Chart, we were able to conceptualize 5 main designs: The Flat Hiker, Magnetic Hiker, The Businessman, and 2 types of Track Shoes.

The Flat Hiker

The Flat Hiker was designed for the hiker on the go. The main features of this combination are the high top topsole and flat bottom outsole. Materials-wise, this shoe utilizes vegan/responsibly sourced leather [topsole], recycled jeans [midsole, support], recycled plastic bottles [outsole], and a silicone sleeve to protect the mechanism against the elements. Some aesthetic features include hemp laces for tightening, a heel loop, a hexagon pattern on the bottom of the outsole, and a stamped delta on the heel. Regarding the connecting mechanism, the Flat Hiker will include a track with a lip, which includes a male & female connection on the topsole and outsole, respectively. This track will culminate with a snap wedge similar to a buckle on a backpack that will snap in place. To release, two buttons will be located in the back of the heel to release the wedge.

The Flat Hiker

The Flat Hiker

Magnetic Hiker

The Magnetic Hiker was designed for someone with a casual trip to the park. The main features of this combination are the mid-cut topsole and hiking boot outsole. Materials-wise, this shoe utilizes waterproof knit [topsole] & recycled tires [outsole]. Some aesthetic features include Icelandic inspired knit pattern, built-in support in the outsole, a heel loop, recycled rubber piping. Regarding the connecting mechanism, the Magnetic Hiker will have pin magnets around the edge with a stabilizing magnet in the toe, as well as a mechanical pin to prevent sliding.

Design Ideas

Design Ideas

Elder Businessman

The Elder Businessman was designed for the older gentleman who wants little to no effort in putting on his shoe. The main features of this combination are the mid-cut topsole and flat-bottom outsole. Materials-wise, this shoe utilizes vegan/responsibly sourced leather [topsole] & cork [outsole]. Some aesthetic features include velcro straps, a stamped delta on the heel, and a diamond pattern on the bottom of the outsole. Regarding the connecting mechanism, the Elder Businessmen will have a locking cylinder in the heel that will activate a pin, in addition to a tooth-like horizontal track.

The Businessman

The Businessman

Running Shoe #1

The 1st Running Shoe, also known as "Sport Mode" was designed for the average track athlete. The main features of this combination are the low cut topsole and running shoe outsole. Materials-wise, this shoe utilizes a waterproof mesh [topsole] & recycled rubber tires [outsole]. Some aesthetic features include a tightening knob & wire, a stamped delta on the heel, and a diamond pattern on the bottom of the outsole with spike mounts for competition. Regarding the connecting mechanism, Sport Mode will have a male-female track that utilizes clasps on the exterior walls.

Running Shoe #1

Running Shoe #1

Running Shoe #2

The 2nd Running Shoe was designed for the athlete who throws. The main features of this combination are the high top topsole and flat bottom outsole. Materials-wise, this shoe utilizes waterproof mesh [topsole], a hard plastic [heel support], responsibly sourced cloth [topsole], & recycled rubber tires [outsole]. Some aesthetic features include recycled laces for tightening and a tiger-striped outsole pattern on the bottom. Regarding the connecting mechanism, the 2nd Running Shoe will include a track, which includes a male & female connection on the topsole and outsole, respectively. This track will utilize a snapping mechanism similar to a Tupperware container.

Running Shoe #2

Running Shoe #2

Strengths & Weaknesses

After taking a look at all of the designs presented after the concept design phase, the team objectively looked for pros and cons of each design. This involved looking at each aspect involved in an individual design. From this, we were able to derive a chart that characteristically breaks down every part of each design. This allowed us to better visualize what worked and what doesn't in the long run regarding manufacturability, aesthetics, and function.

Strengths and Weaknesses Derived From Team Meeting

Strengths and Weaknesses Derived From Team Meeting

You can also download an excel spreadsheet with each of the strengths and weaknesses here.

Feasibility: Prototyping, Analysis, Simulation

Inputs and Source

  1. Engineering Requirements
  2. Concept Selection

Morphological Chart & Pugh Analysis

Generated Morph Chart

Generated Morph Chart

Pugh Analysis

Pugh Analysis - Running Shoe #1 Datum

Pugh Analysis - Running Shoe #1 Datum

Pugh Analysis - Flat Hiker Datum

Pugh Analysis - Flat Hiker Datum

Pugh Analysis - Elder Businessman Datum

Pugh Analysis - Elder Businessman Datum

Pugh Analysis - Magnetic Hiker Datum

Pugh Analysis - Magnetic Hiker Datum

Pugh Analysis - Running Shoe #2 Datum

Pugh Analysis - Running Shoe #2 Datum

Inputs and Source

  1. Engineering Requirements

Concept Selection

This consists of two elements: concept screening and concept improvement. Below, you will find our process that includes these elements and more:

Our team used the selected criteria to compare concepts using Pugh analysis seen in the above sections. From this, we were able to create the strengths and weaknesses of each design that was featured above.

Selection Criteria Table

Selection Criteria Table

Major Findings

From the above Pugh Analysis and Strengths & Weaknesses chart, we recognized the need for a multipart joining mechanism with both a passive and active component such as a track and a clasp. We also identified some ideas we will not be moving forward with and why.

Systems Architecture

For the Systems Architecture portion of Systems Level Design, we wanted to provide an objective look at the system in consideration.

Systems Architecture

Systems Architecture

This is a high-level view of the elements and subsystems of our modular shoe. This includes two interchangeable topsoles, three interchangeable outsoles, and one midsole that acts as the joining mechanism between the two. The system will be operated by the end user who will begin by selecting their desired topsole and outsole. The user will then align the midsole track mechanism with the corresponding track component of the outsole. The user will put on the top sole like a traditional shoe and flip up the silicone sleeve around the edge of the shoe. The user will then step onto the midsole aligning the midtrack with the corresponding topsole component. From there the user will flip down the silicone sleeve from the top sole around the edge of the outsole securing the shoe.

If you'd like to view this photo in a PDF format, click here

Inputs and Source

  1. Engineering Requirements
  2. Functional Decomposition Tree
  3. Concept Development

Risk Assessment

At this point in the project, the systems design phase, the risk factors that we assessed during the problem definition phase carry over to the systems design phase with little to no changes. The risks we identified largely involve a physical shoe concept and the associated parts with the concept. Risks like ankle support, tread security, and others associated with the shoe, will not change until we can successfully create a physical shoe concept to test and analyze. Once we have generated a working prototype, we can then evaluate our risk matrix for any shortcomings.

The risks involved with the team and societal norms haven’t changed either. We have yet to perform any human testing due to not having a physical shoe concept yet. Without a shoe to test, we will not be performing any human testing. The risks associated with the team haven’t changed as well. Those risks were implemented originally with the entire project in mind and they will be in place for the entire duration of the project.

Risk Matrix from Problem Definition Phase

Risk Matrix from Problem Definition Phase

Design Review Materials

PowerPoint Presentation

PowerPoint Presentation - PDF Form

Plans for next phase

Team Plans

Individual Plans

Lydia Yeckley

Mickey Evans

Nick Amato

Haley Gallagher

End of Cycle Peer Review

Peer Review For Systems Design Phase

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