[PSUBS-MAILIST] calculation
hank pronk via Personal_Submersibles
personal_submersibles at psubs.org
Tue Jul 7 18:59:24 EDT 2015
Alan,
I am starting slip testing tomorrow, I just bonded the gasket to the test chamber.
As for testing the sub, I am using my barge with winch to lower the sub with my video camera recording. I will turn the radio on and talk to the sub from the surface. I will tell the sub the depth constantly and it will be recorded.
Hope to do this next week, it is a big effort, I have to truck the barge 6 hr to the lake, then drive home, then come the next day with the sub. Maybe my wife will let me haul her car with the barge on the trailer so I can get home. :-)
Hank --------------------------------------------
On Tue, 7/7/15, swaters at waters-ks.com via Personal_Submersibles <personal_submersibles at psubs.org> wrote:
Subject: Re: [PSUBS-MAILIST] calculation
To: "Personal Submersibles General Discussion" <personal_submersibles at psubs.org>
Received: Tuesday, July 7, 2015, 6:01 PM
Alan,When
I was down diving with Karl Stanley earlier this year he
showed me the veiwport that cracked. It was caused by him
taking his sub to deep and the body warped putting side
pressure on the veiwport. After that he derated his depth.
This was on his first sub
CBUG.Thanks,Scott Waters
Sent from my U.S.
Cellular® Smartphone
-------- Original message
--------
From: Alan James via
Personal_Submersibles
<personal_submersibles at psubs.org>
Date:07/07/2015 4:27 PM (GMT-06:00)
To: Personal Submersibles General Discussion
<personal_submersibles at psubs.org>
Cc:
Subject: Re: [PSUBS-MAILIST] calculation
Hank,I remember
Karl Stanley (or someone else) saying he cracked a dome at
depthdue to an
unexpected contraction of the pressure hull.Just in
case everything is not right; how about an unmanned
dive!You could
record any noises by putting something like your cel phone
in the hullon
record.Then
synchronize a watch on the support boat & record what
depths you havethe sub
down at at what times. So if you get a big "Crack"
on your recording you will be
able to tell at what depth it happened.Easier
said than done I know, but probably worth it.Cheers
Alan
From: hank pronk via
Personal_Submersibles
<personal_submersibles at psubs.org>
To: Personal
Submersibles General Discussion
<personal_submersibles at psubs.org>
Sent:
Wednesday, July 8, 2015 12:26 AM
Subject: Re:
[PSUBS-MAILIST] calculation
Alan,
When my
dome made the mystery noise, I was at 100 feet deep. That
puts about 18 tons on the dome. I think it was either the
straps were able to relax and find their happy place, or,
the super cold water made the dome contract.
Hank--------------------------------------------
On Mon, 7/6/15, Alan James via
Personal_Submersibles <personal_submersibles at psubs.org>
wrote:
Subject: Re:
[PSUBS-MAILIST] calculation
To:
"Personal Submersibles General Discussion" <personal_submersibles at psubs.org>
Received: Monday, July 6, 2015, 9:00 PM
Hank,I was
looking at some Deep Worker photos. The dome retaining
bandslook like
they can be
wound tight from a central point at the
top.I am
wondering if they pre stress these
significantly so that
there is less
movementwhen they
are compressed at
depth.
Also I
commented
on your retaining system when I first saw it, that
I thought thevertical
floatational force might move it upward, or the dome
pivot
out from the bottom.Perhaps
you could exert more pressure on the dome with
your clamping
system?
Alan
From:
Alec Smyth via
Personal_Submersibles
<personal_submersibles at psubs.org>
To: Personal
Submersibles General Discussion
<personal_submersibles at psubs.org>
Sent: Tuesday,
July 7, 2015 12:31 PM
Subject: Re:
[PSUBS-MAILIST] calculation
Does
the
window seat have some sort of inside
diameter edge? I would
think if it does
not, then its pretty much guaranteed to
slip with or without grease - with grease being the
quieter
less-terrifying option.
Best,
Alec
On Mon,
Jul 6, 2015 at 6:50 PM, hank pronk via
Personal_Submersibles
<personal_submersibles at psubs.org>
wrote:
Sean,
Thank
you for the input, I think I will just use weights
like Alan says.
I am making a fixture to simulate the EPDM
gasket compressed
under my dome. I want
to test it with grease and
without. I
will squeeze the gasket in the fixture then
push the top plate sideways with a pusher bolt to see if
the
gasket allows movement. I want to
make sure my dome can
expand and contract
at depth.
Hank
--------------------------------------------
On Mon, 7/6/15, Sean T.
Stevenson via Personal_Submersibles
<personal_submersibles at psubs.org>
wrote:
Subject: Re:
[PSUBS-MAILIST] calculation
To: "Personal Submersibles General
Discussion"
<personal_submersibles at psubs.org>
Received: Monday, July 6,
2015, 9:08 AM
Hank - the force developed
is dependent on the
stiffness of both the bolt material and of the specimen
you're pushing on.
You can't necessarily
equate
this directly to torque
because of friction in the bolt
threads and at the bolt end contact, and of
course the
elasticity
of the bolt itself. You can only estimate
it.
There are many
online tools for calculating the
developed
tensile force
in a bolted connection, for example, but
these
consider only the
bolt as the deformable element, and
require an accurate estimate of coefficients
of
friction,
and this will change with lubrication. As
you complicate
the
system, it becomes more geometry
dependent.
A 1" -
8 UNC 2A thread is 8 threads per
inch, so a set number of turns will give you
the
approximate
axial displacement (0.125" per
revolution -
approximate
because the bolt will change length
under load). If you
assume a rigid fixture, then your strain is equal to
the
overall change in length (calculated from # of bolt
turns),
divided by the gauge length (distance over which the
length
change occurs, which would be the length of your
specimen
measured between the rigid fixture and the end of your
jack
bolt). Compressive or tensile load is then calculated
based
on
the modulus of elasticity of the specimen.
Alternatively, you can
measure the load (make the bolt
or
fixture into a load cell
or strain gauge the specimen)
and
calculate the material
properties.
Load, axial
displacement, modulus. You need any
two to calculate the third.
What are you making / testing?
Sean
On July
6, 2015 6:26:49 AM
MDT,
hank pronk via Personal_Submersibles
<personal_submersibles at psubs.org>
wrote:
Hi
all,
I
need help, can anyone tell me how to
calculate how much
force a bolt can push or pull using a torque wrench to
turn
the
bolt. So how many foot pounds of torque does it take
to
rotate
a bolt to create 250 lbs push with a 1 in
coarse
thread bolt. I
need to make a test fixture.
Hank
Personal_Submersibles
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