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My name is Steve Fletcher and I am an Engineer for the U.S. Naval Facilities
Engineering Command. We are doing testing of which I cannot fully disclose
some of the details. I apologize if some of the following seems vague, but
I will do my best to explain. A professor at Arizona State University was
kind enough to point me to this Listserv to help solve my problem.
We conduct a test on a type of structural flooring after it has been
stressed in specified ways. The test is supposed to simulate a person
jumping down onto the structure. We must ensure that the structure is
capable of handling a 300 lb person jumping onto the surface after it has
been stressed. There is the potential for people to be jumping from a
maximum height of five feet (1.5m) onto the structural flooring and such is
the height we drop the weight from. We currently use a 300 lb drop weight
to do this. The "drop weight" is a welded steel structure that has two
rectangular steel "feet" upon which it hits the landing surface. Under
unstressed conditions, the structural flooring is rigid and does not visibly
deflect upon the impact of a real human landing on it. The structural
flooring may deflect a fraction of an inch, if at all.
Some of my colleagues have called this method into question and are saying
that it is not representative of a 300 lb person jumping onto this surface
from a height of 5 feet. Being an engineer, I reviewed the physics behind
this reaction and agree that this may be over-kill. I have done some
research and have found limited information on this topic. Most of what I
have found is the ground reaction forces on lighter athletes jumping from a
height of 1'-2'. I found that the GRF of a female jumping onto a surface
from a height of 0.47m is about 5.7 times their weight.
My goal is to find the weight of a steel "drop weight" that generates an
equivalent force to that of a 300 lb person landing on a rigid surface from
a height of five feet.
Another idea I had was to add springs to the drop weight to distribute the
force over a length of time similar to a person's knees bending. The
equivalent weight method is much more desirable.
Thank you in advance for any insight you can provide.
Steve Fletcher, E.I.T.
Engineer
Naval Facilities Engineering Command
Sfletch47@gmail.com
Engineering Command. We are doing testing of which I cannot fully disclose
some of the details. I apologize if some of the following seems vague, but
I will do my best to explain. A professor at Arizona State University was
kind enough to point me to this Listserv to help solve my problem.
We conduct a test on a type of structural flooring after it has been
stressed in specified ways. The test is supposed to simulate a person
jumping down onto the structure. We must ensure that the structure is
capable of handling a 300 lb person jumping onto the surface after it has
been stressed. There is the potential for people to be jumping from a
maximum height of five feet (1.5m) onto the structural flooring and such is
the height we drop the weight from. We currently use a 300 lb drop weight
to do this. The "drop weight" is a welded steel structure that has two
rectangular steel "feet" upon which it hits the landing surface. Under
unstressed conditions, the structural flooring is rigid and does not visibly
deflect upon the impact of a real human landing on it. The structural
flooring may deflect a fraction of an inch, if at all.
Some of my colleagues have called this method into question and are saying
that it is not representative of a 300 lb person jumping onto this surface
from a height of 5 feet. Being an engineer, I reviewed the physics behind
this reaction and agree that this may be over-kill. I have done some
research and have found limited information on this topic. Most of what I
have found is the ground reaction forces on lighter athletes jumping from a
height of 1'-2'. I found that the GRF of a female jumping onto a surface
from a height of 0.47m is about 5.7 times their weight.
My goal is to find the weight of a steel "drop weight" that generates an
equivalent force to that of a 300 lb person landing on a rigid surface from
a height of five feet.
Another idea I had was to add springs to the drop weight to distribute the
force over a length of time similar to a person's knees bending. The
equivalent weight method is much more desirable.
Thank you in advance for any insight you can provide.
Steve Fletcher, E.I.T.
Engineer
Naval Facilities Engineering Command
Sfletch47@gmail.com