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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
6. 6
effects of the pressure on the collector, the pressure will be utilized to move the mechanical
component necessary to obtain a soil sample.
DesignCriteria:
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:
Goals
Minimum
Cost
Reliability
Ease
of Use
Minimum
Maintenance
Versatility
Total
Rating
Weighting Factors
Design Alternatives 90 100 60 50 80 Total
A. Sideways Apparatus 10 6 5 10 5 2700
B. Straight Pipe Apparatus with SandHolder 8 7 7 8 7 2800
C. Straight Pipe Apparatus withScooper 8 8 7 8 8 2980
D. U-shapedPipe withVacuum 7 8 8 10 7 2970
E. U-shaped Pipe with Vacuum and Scooper 6 9 7 7 10 3010
F. Straight Pipe with VacuumandScooper. 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
4. Minimum Maintenance
5. Versatility
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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.
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.
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RevisedPrototype 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
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.
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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
Labor $100
Total $182.90
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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
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.
