Deep Sea Soil Collector- A Component of T.I.M.

ME 4202 - Senior Design II

Dr. Valmiki Sooklal

By: E.J. Roe and Michael Watson

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Table of Contents

Executive Summary 3

Introduction 4

Design Criteria 5

Concepts 6

Dummy Prototype 9

Rapid Prototype Design 10

Bill of Materials 21

Costs 21

Testing

21

Initial FEA/CFD Analysis 22

Calculations 22

Optimization 23

Final Bill of Materials 23

Final Costs 23

Recommendations 24

Conclusion 24

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3

Executive Summary:

The goal of this report is to present the engineering process of the Deep Sea Soil Collector.

Investigating ocean life at deep sea depths can be very challenging for the science community in

general. This report will present a solution to easing the investigative process by developing a

Deep Sea Soil Collector to collect silt at the bottom of the ocean. Six designs were investigated

along with other ideas which involved details of differing design being combined as alternatives.

A decision matrix with a specific criteria was implemented in determining the most viable design

for operation. The design involving a u-shaped PVC pipe with a vacuum and scooper was

selected and optimized according to prototype testing, engineering analysis and optimization.

Due to optimization, the chosen design evolved and differs from the initial design. The optimized

design will meet all required operation and design criteria.

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Introduction:

The project is a design component of an apparatus designed to travel 6 miles beneath sea level to

the bottom the ocean. The task is to collect water and soil samples and if possible, maintain the

pressure of the sample upon retrieval. Maintaining the pressure within the collectors allow for

organisms to remain alive when the apparatus is being retrieved from the surface. The living

organisms will allow for further research and examination in regards to the environment at the

ocean floor. The quality of human living may benefit due to the knowledge of previous medical

discoveries related to ocean life.

William Howard of AMEC is the leader of the project and exploration which will retrieve water

and soil/silt samples from the Hadalpelagic Zone of the ocean. The project is known as T.I.M.

and will consist of mechanical soil and water collectors, as our team is responsible for the design

of the soil collector. The design will have to meet a particular set of criteria established by Mr.

Howard along with the environmental conditions of submerging and remerging at an extreme

ocean depth.

The design will function mechanically to retrieve the soil without the use of a power source.

Without the use of a power source, the existing operation challenges are water temperature,

extreme pressure and unpredictable surface terrain. The water temperature will dictate the type of

materials used to manufacture the soil collector. The manufacturing materials will contain a low

susceptibility and ductility to temperature changes. The material will have to withstand extreme

pressure changes and various stresses to avoid the destruction of the collector. With the negative

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effects of the pressure on the collector, the pressure will be utilized to move the mechanical

component necessary to obtain a soil sample.

Design Criteria:

1. Operation must be completely mechanical

2. Apparatus must weigh no more than 30 lbs

3. Cost of manufacturing will be $200 or less

4. Must withstand a seawater pressure of 16,000 psi

5. Must withstand impact with rock

6. Function in a temperature range of 0oC to 45oC

7. The goal for factor of safety is 2.5

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Concepts:

As ideas were generated, six concepts were developed and evaluated based on reliability, ease of

use, minimum maintenance and versatility.

Design A:

Design A is a syringe type apparatus which will scrape soil/rock from the ocean floor. The

apparatus will operate from a sideways position and use the pump portion of the syringe to

collect the soil/rock. Once the process of the collection is complete, the apparatus will be sealed

shut from the water pressure.

Design B:

The apparatus is have a bottom portion shaped as a cone, which will penetrate the ocean floor,

thus collecting the soil/rock. The cone will have a mechanical device in which a release will be

activated to allow the water pressure to move the cone up towards the collector and sealing the

sample inside the collector.

Design C:

Design C is similar to design B with the exception of design C having a scoop, which will

initially be in an open position during the exploration. The apparatus will penetrate the ground

with the scoop portion, thus collect a sample by mechanical closing the scoop.

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Design D:

The fourth design consist of a u-shaped tube which will operate as a vacuum. The right side of

the sketch includes an open air-space with a breakable meniscus. The area between the stoppers

will contain vegetable oil, which is less dense than water. The remaining portion of the pipe will

be pre-filled with water. Once the right side of the apparatus makes contact with the bottom of

the ocean, the mechanism will slide upward, making contact and puncturing the meniscus. This

will allow the pre-filled water to escape into the ocean, thus allowing the stopper to slide upward

due to the less dense oil and the pressure from the seawater. A vacuum will be created, thus

collecting the soil into the apparatus.

Design E:

This design is an enhanced version of design D. It combines the main ideas from design 3 in an

attachment to the vacuum end of design D. This will have dual scoopers that move and scoop

towards the opening where they meet and seal its contents inside them.

Design F:

Design F will consist of a straight pipe with a stopper containing vegetable oil. The premise is a

mechanism triggering the release of the vegetable oil in a separate container, creating a vacuum,

collecting the soil and the scoopers being a 2nd reinforcement to collect the soil. The scoopers

will shut and seal the pipe, rendering the escape of the soil.

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Decision Matrix:

GoalsMinimu

m

Cost

Reliabilit

y

Ease

of

Use

Minimum

Maintenanc

e

Versatilit

y

Total

Ratin

g

Weighting Factors

Design Alternatives 90 100 60 50 80

Tota

l

A. Sideways Apparatus 10 6 5 10 5 2700

B. Straight Pipe Apparatus with Sand

Holder 8 7 7 8 7 2800

C. Straight Pipe Apparatus with Scooper 8 8 7 8 8 2980

D. U-shaped Pipe with Vacuum 7 8 8 10 7 2970

E. U-shaped Pipe with Vacuum and

Scooper 6 9 7 7 10 3010

F. Straight Pipe with Vacuum and Scooper. 5 7 8 10 8 2770

Table 1: Decision Matrix

The methodology of the matrix is based on using a decision factor to decide the most optimal

option based on a set of criteria. In this case, the criteria is,

1. Minimum Cost

2. Reliability

3. Ease of Use

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4. Minimum Maintenance

5. Versatility

Each category is assigned a weighted factor on a scale from 0-100 based on importance in

regards to the objectives. Each design is rated on a scale from 1 to 10 for each goal, which is

known as the rating factor. The rating factor is multiplied by the weighted factor to generate a

total rating for each design and the highest total amongst each design is deemed the most

optimal. In this case, Design E is the most optimal and will be explored as the design to

prototype and implement.

As time progressed with the selected design, the scoopers were eliminated and a straight pipe

was implemented as opposed to the curved pipe to eliminate over-engineering. A balloon with

olive oil would serve as the device to create the vacuum. With olive oil having a lower specific

weight than seawater, an upward force is created to lift the stopper, thus creating the vacuum.

Initial 3D Prototype:

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This prototype is an enhanced version of the U shaped vacuum scooper. The U function has been

reduced to a single tube as the oil is now contained inside a balloon which is inside the tube. The

floating balloon pulls the cord with scoopers along the ground and into the tube with a stopper at

the end to contain the collected soil. This design spawned a dummy prototype as such was

achievable readily due to the design’s simplicity and low costs.

Dummy Prototype:

It was not intended to meet the full criteria of the project, but rather to test the idea at a basic

level to confirm the major principle components did their functions intended. This dummy test

exposed a flaw in the design which was rather unexpected as it was not revealed in the

calculations or the simulations and it also did confirm that our idea did work, but not as well as

expected.

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The test consisted of a 1.5 ft. long and 4 inch diameter PVC pipe that was capped at both ends.

The caps had holes drilled through tem vertically. Inside the pipe contained a balloon filled with

vegetable oil and a pipe cleaner attached to the end of knot which sealed the balloon. The

exposed flaw was in the balloon itself as it proved to be very fragile. With very careful handling

the device ran a couple test in which it was submerged in water with one end pressed against a

sand base. The balloon did in fact float up and pulled the pipe cleaner along with it and sucked

up some of the sand. The amount of care needed to make the balloon reliable deemed the test a

failure.

Revised Prototype Design:

Due to complications with a completely independent design (not relying on other components of

TIM), an alternative similar to design C was brainstormed with the group and Mr. Howard,

which led to the following design.

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FEA/CFD Analysis:

Up to this point our desings only had to pass simple Factor of Saftey requiremtns as the client

had not requirened anything further as more emphais had been placed on function. With this

design we were informed of further requirements and as such we had to go much more indepth

with the FEA analyis and as such we decided this would be the best point to show our work.

Figure X

The above figure is of a drop test performed at 5 mph. With the revampled set of requirements

the client requested to see how fast of an impact the design could handle. The reason for this was

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that it had recently been determined that out componet of T.I.M. was to be the furthers down and

thus the first to impact the soil. This means that our compnet would determine how fast the entire

device could travel on its way to the bottom of the ocean. The resulsts from the test show that at

5 mph displacemnts of 0.01 inces occurred. This was the absolute limit as any more than that the

componet would fail.

As with the previous models Factor of Saftey anaylsis was permofmed. Every componet was

evualted individually as Solidworks could not handle the entire model at once. For the sake of

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saving space within this report the componet of most concern was shown. The 4 in PVC pipe.

The other componets did not fair so well with the hand calculations or the FEA (as shown in the

chart below) and so this desing was rendered to be a proof of concept protoype. The 4 in PVC

compnet was of concern as it did pass the hand calculations and confirming this in Solidowrks

would mean significant cost savings in the production model. The above figure shows that with

the 16,000 Psi pressure applied the pipe passes with a FoS of 4.3 which is above the clients 1.2

goal.

Calculations:

Final Prototype:

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The above photo is of our proof of concept prototype. This design was tested at a Carters lake in

Northern Georgia at a depth of 25 ft. While this test was in shallow depth and also in fresh water,

valuable information was obtained. This design does have a minor flaw. The prototype works

fine in air, but the increased viscosity of water proved to hold the plunger in place. Upon arrival

to the surface the device had not separated. The metal frame was still over the PVC pipe until

breaching the water. Then the device opened in the air. The problem was that the water inside the

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pipe was not able to evacuate thus not allowing the plunger to move. To remedy this, holes

should be drilled into the top of the metal frame to allow the water to be pushed out by the

plunger.

Final Bill of Materials and Cost:

Component Cost

PVC Casing $8.00

PVC Stopper $4.00

PVC Rod $3.00

Nuts and Bolts $2.00

Steel Rod $8.57

Fishing Line $0.13

Eyelets $0.20

Steel Ring $4.00

Steel Frame $46.00

Track $5.00

Scoopers $2.00

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Labor $100

Total $182.90

Recommendations

We would suggest that different attachments be made to the apparatus to better suit the needs of

the tester. This may be a more aggressive scooper in which the suction would be a secondary

method of capture and the scoopers would be primary. This would require knowledge of the

sample are in that it was be soft. Relying on scoopers in a potential hard environment would have

a high chance of zero collection as the scoopers would not be able to cut through rock for

example. The rail system is fairly modular and different scoopers design could be swapped on at

a later design phase if a need does in fact arise.

Conclusions:

The client put an emphasis on function as this was a project into unknown areas of earth. Only

four previous expeditions into the Mariana trench (bottom of the ocean) in human history. This

meant that little data was available for design requirements. The apparatus did not meet the

original requirements of being a production worthy design, however it is close enough that with

some simple material changes and it will be. The goal of $200 was met with the ultimate goal of

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being under $1000 should be attainable even after the material change as the largest component

(4 in PVC) will still be used. This means that the ultimate goal of the project, to come up with a

functional design at a low cost relative to previous expeditions, has been met.

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