P14415: Subsystem Design Review

Patrick Morabito John Wilson Michael CoffeyNathan ConklinSamuel Svintozelsky

Agenda• Background and Recap Information

• Engineering Requirement Flowdown

• Subsystems

• Proof of Concepto Prototypingo Economic Analysis

• Test Procedure & Risks

• Moving Forward

Background InformationInadequate sanitation is a major cause of

preventable illnesses in children around the world. According to UNICEF, diarrhea alone causes over 1.6 million deaths in children under 5. These illnesses can easily be prevented by improving sanitation. However, cost is a major barrier limiting the adoption of sanitation in Haiti.

Peter Morgan’s Arborloo is a simple latrine built over a small pit, which when filled is then moved to a new pit location. The old, filled pit then has vegetation planted on top of it, such as a fruit tree.

New Learnings

• Meeting with Johnnyo Low-cost reaffirmed as critical constrainto Building capabilities explored

• Mock up buildo Hole size requirement revisited

o Platform size improvementsxxx

Engineering Requirements - Updates

• S4-Maximum squat hole diameter

• S8-Complexity of tools needed

Critical Requirements Recap• Cost

o Continuously surfaces as primary requirement

• Weighto Crucial to remote users

• Load Bearing Abilityo Main functional requirement

(From Engineering Requirements) https://edge.rit.edu/edge/P14415/public/Project%20Planning%20Phase/Engineering_Requirements_14415.xls

Highlighted Functions

• Guides Raw Sewage• Supports Weight• Separates User from the Pit• Establishes Barrier Between User and

Waste

Subsystems

• Manufacturing Process

• Material Selection

• Shape & Form

Manufacturing Processes

Materials ConsideredCost Matrix

Acquired Quotes for these materials are a little too costly.

Design #1

• Explored Rib Design Models • Built Full Scale Mockup • Built Vacuum Formed Scale Model• Two Directions

Design #1 Rib Design Set up

2000N Load

Fixed at 4 corners

Model Tensile Strength: 9.5 * 10 ^7 N/m^2Fixed at 4 corners of baseLoad: 2000N Load*Refer to reports for mesh information

Design #1 Exploration

Design #1: Highlighted Beta Designs

Design 1 Rib Design Summary

Design #1 - Half Scale ModelPurpose:

● Test ABS Plastic● Test vacuum forming capabilities

Design #1 - Half Scale Model Cont.

Design #1 - Half Scale Model Cont.Lessons Learned

Weak/Thin Corners

Poor edge draft/vacuumStrong ribs & durable top surface

Design #2

• Full Scale Mockup• Material Selections• Cost Analysis

Design #2 Cost Analysis• 1 x 6” Design

o 11/16” thicko 14’ Plastic board o 10’ 2x2 ribbingo $43.7 total

• 10-¼ x ¼”o ¼” thicko 1.5 12’ boardo 10’ 2x2 ribbingo $35.66 total

Cost Analysis - Design #1 & #2 Full Scale Models

Designs #3 & #4

• Not Feasible Designs• Cardboard Models

o Difficult to sit and stando Scale required to cover hole required separate

supporting base

• Better as Seatso Can easily be integrated with a bucket

Updated Risks Assessment (Technical)

Updated Risks Assessment (Project)

Updated Risks Assessment (Team)

Test Plan - Revisited

Updated Project Plan

Key Decisions from Subsystem Phase• Design 1: Two Directions

o Plastic Ribbing & Supportso Recycled/Repurposed Material

• Design 2: “Local Industry”

• Designs 3 & 4: No Longer Full Designso Possible Seat Integration

• Possible Manufacturing Processeso Vacuum Formingo Rotational Moldingo “Kit”o Recycled

Moving Forward - Next Phase

• Design 1: Repurposed Materials Method• Design 2: Support Structure• Lid Designs• Seats (Upgradable)• Cleanability

Questions?