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Design Proposal

Underwater Video Coring

By:Curtis McCabe, Juan DeLeon, Jonathan Riestra, and Vicki Banh TEAM 13

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Problem Definition

High Priority Objectives

First priority for our Team will be the design of the complete system that will encase the camera, lens, lighting and angled mirror
Design of window to view sediment
Wet mate connector used to connect Ethernet cable to camera

Second Priority Objectives

Prototype of the System
Tests of the System in action, at depth or pressure equivalent.

Other Constraints and Issues

Water tight at depth of up to 60 ft
Scratch and damage resistant window (sapphire)
Size- everything must fit in a 2-3 inch diameter pipe (square or round)
Cold Temperatures, 50F to 56F
Budget of $3000 ($1500 Machine Shop/$1500 Equipment and Parts)

Riestra

Define problem and goals for our project, refer to project description for inspiration.

We need to create a new, simpler, cheaper, and faster way to look at sediment contamination. the department of defense spends billions on monitoring and cleaning up contamination in our harbors. We are tasked with making a housing that will contain an industry grade camera to take live video of the inside of a core sample hole, without ever taking the sample out of the ground. the housing must be water proof and stand up to pressure at 60 ft underwater as well as the forces that will drive it into the sediment. Our housing will have a window that will enable the camera to view the sediment and possible contaminants up close and personal. The camera will transfer data and be powered via an ethernet cable that will run all the way up to the boat.

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Risk Reduction: Key Take-Aways

O-rings tested at 100 psi/690kPa overnight
Both worked
Our camera will be dry

Bolted option vs. threaded option.
Machining feasibility
Avoid seal welding through threaded joints

Riestra

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Risk Reduction: Key Take-Aways

The Smallest Load Value, that is the minimum load to buckle our housing under the least ideal conditions is

F=2115kN (square shell)

Since the Vibrocorer applies an approximate 22kN, it does not apply enough force to buckle the Housing. (Stainless Steel E=180 GPa)

Riestra

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Analyzed a pyramid, cone, triangular prism (1), and cylinder diagonally sliced in half (2) using conservation of momentum

The velocity profile at each cross section of the wedge was found

Design Decision: Wedge

Banh

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Wedge Shape

Triangular prism is the second most optimal shape in penetration after cylinder sliced in half

Difference is minimal; prioritize unaltered sediment flow

Longer the wedge = easier penetration

Banh

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Design Decision: Tip Shape

McCabe

Back this up with analysis, equations, and numerical results.

Flow analysis

The left sides of these pages show the profile of the tip used and the right side shows fluid flow represented by pipes. The pipes change direction based on how water would flow around the object. In these pictures one can see where material would flow when the tip is forced into the ground. The color shown in the pictures refers to the speed of the flow in that location but this is not important for the purposes of this analysis.

In Our first example we have the Pyramid shape tip. This tip is the most straight forward design for ensuring the housing goes into the sand/sediment with the greatest of ease. One can see that the material will be disturbed greatly in all directions so a better tip design that preserves the sediment to get a better picture must exist.

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Design Decision: Tip Shape

McCabe

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Design Decision: Tip Shape

McCabe

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Design Decision: Tip Shape

McCabe

In our fourth Example, Affectionately called the Bunny Ear shape, we see a much more complicated design for the tip but we regain a very similar disturbance minimizing effect at both the left and right sides of the tip/housing. If one compares the wedge with the bunny ear examples the right sides are almost identical. Since the Bunny Ear shape is also symmetrical there will not be any problems with the direction of the pipe moving off the vertical. One set back of this design is that it will be much more difficult to manufacture. Another problem could be the strength of the material used for the tip, the right and left sides could break since they are thinner and have a shearing force pointing outward from the center line.

Due to these concerns and recommendations from our sponsor we decided that the best tip to use would be the simpler wedge shape. The wedge disturbed the least sand and is much easier to machine. we will have to design a way for the piping to be guided straight down in the presence of the shearing force we were concerned about.

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Design Decision:

Materials Used for Housing

Main concerns:

Buckling
Vibration Cycles
Corrosion
Price

Solutions:

Materials with large Young’s Modulus increase Buckling Force
Materials with high resistance to cycling loads

DeLeon

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Design Decision:

Materials Used for Housing

Solutions:

Stainless steel

Reasonable price
Corrosion resistance in marine environments

De Leon

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Design Decision:

Window Type

Sapphire scratch resistant
Conflat by Rayotek
Stainless Steel bonded to Sapphire
O-ring seal
Resistant to 145 psi/10^6 Pa

De Leon

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Design Decision: Wet Mate

Riestra

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Design Decision: Wet Mate

Riestra

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Design Decision: Lighting

Constraints:

Size
minimum brightness > 6.25 lumens
not too bright (glare off sapphire window)

Can be fixed with anti-glare coating

color should be white (no interference with sediment color)

Best:

Choose: COM-12014 (bottom)

lights are surface mounted rather than through hole mounted (less bulky)

Given component (top) is the older version

Considered as an outdated model and is not in stock anymore

Banh

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Design Decision: Lenses

Electro focusing allows controlling camera f-stop using

a microcontroller.

-Cannot focus camera manually

-Control f-stop using a microcontroller (arduino)

Size Constraint

-Lens must be greater than an 1 in./25.4mm (as large as possible)

-max diameter no larger than 2.87 in./72.89mm

C/CS mount is preferred

-compatible with most cameras including our working given camera

Focal Length - (Zoom) still need information on resolution and

magnification size; not distort pixels

-18mm-55mm- ranges from naked eye view to less magnified

-55mm-250mm- ranges from naked eye view to more magnified

Riestra

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Design Decision: Lenses

Canon Models:

EF-S18-55mm f/3.5-5.6 IS/EF-S55-250mm f/4-5.6 IS STM

-Electronic f-stop (can control using microcontroller)

-max diameter-70mm/2.76in

-f stop limit f/5.6. (focus)

-amount of allowable light

-Image stabilizer- compensates for camera

shake

-May need C/Cs adapter depending on the camera we purchase

-$200-$300

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Future Decisions

Mounting camera and mirror internally
Design to reduce vibration for imaging/video
Attachment to existing core pipe
Paint job

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Proposed Design

Square tube housing
Better for Buckling

Stainless Steel material
Corrosion resistance in marine environment & high Young Modulus

Wedge type tip
Provides less sediment disturbances on window side.

O-ring Sealed
Tested to withstand goal pressures

Sapphire Glass
Very scratch resistant

McCabe

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Proposed Design

Assembled Part

McCabe

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Need to Purchase

Products

Wet Mate Receptacle/Connector
Steel Square tube
Camera
Window/Hardware
LED lighting

Costs

$152.12
$ 3.00 / pound
$ 500 [avg price]
$ 150.00 - 600.00
$ 3.95 / unit

Banh

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Machined Parts

Parts

Tip Wedge
Window
Threading
Drill holes

Process

End Mill
Cut out
Taps/Lathe
Bridgeport

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Remaining Questions/Concerns

Waiting for final confirmation on required camera specs from sponsor.
Possible modifications to ballast system of Vibrocorer.
Considering adding a damping mechanism to attach camera to housing.

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Gantt Chart

Upcoming milestones:

Determine friction reduction from vibrations
Purchase components
Start designing for component positions
Build prototype within the next two and a half weeks

DeLeon

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References

Optics Recommendation:

http://www.baslerweb.com/media/documents/BAS1109_White_Paper_Optics_Recommendation.pdf

Magnification:

http://en.wikipedia.org/wiki/Magnification#Magnification_as_a_number_.28optical_magnification.2

Canon Camera Lenses:

^{http://gdlp01.c-wss.com/gds/7/0300003577/01/ef-s18-55f35-56is-en.pdf}

^{http://gdlp01.c-wss.com/gds/8/0300012888/01/efs55-250f4-56isstm-im-eng.pdf}

Simplified Wedge Penetration Velocity Analysis:

http://www.crcnetbase.com/doi/abs/10.1201/b15813-21

LED lights:

https://www.sparkfun.com/products/retired/680

Chris, techsupport@sparkfun.com

Camera Light Intake Needed:

https://books.google.com/books?id=z5_cAwAAQBAJ&pg=PA108&lpg=PA108&dq=lux+needed+for+f+stop&source=bl&ots=zJCdw0bFpD&sig=wkYHpF22HvZCnsA8PpbIuavQhec&hl=en&sa=X&ei=GeoZVciUNcmryATu9oGYDw&ved=0CDkQ6AEwAw#v=onepage&q=lux%20needed%20for%20f%20stop&f=fals