Treehouse Engineering
- Analysis
Analysis-
Quantitative Analysis: Don't Fear the Numbers……
It can be instructive to examine things from a qualitative perspective, where
ratio and proportion are often sufficient tools to create robust solutions.
For thousands of years very large structures were constructed without any
rigorous knowledge of the relationship between imposed forces and the stresses
they create. One might argue that such an approach is sufficient for the construction
of tree houses since it can be very difficult to accurately determine their
inherent load/stress relationships. In this discussion, however, we are going
to make an effort to identify useful numerical solutions to the real world
problems presented by the engineering, design and construction of tree houses.
To put things in perspective we will first review material that may seem unnecessary
to many readers. Some high school students may have mastered Newtonian Physics
and Mathematics, but the typical math skills expected at this level can be
summarized by the following:
Now let us examine Newtonian Physics and Mathematics in a little more detail.
When Isaac Newton was twenty ? years old, the plague had once again swept
through England and, among other things, had forced his classes at Cambridge
University to be cancelled. Confined to the family estate, and in a state
of utter boredom, he noticed that the suns ray's diffracted into their component
colors against the wall of the closet after passing through a narrow slit
created by the partially open door. What rational explanation was there for
his observation? Numerous additional observations produced quite a group of
questions needing answers. He soon realized that the mathematics of the time
did not provide the tools necessary to solve his growing list of unanswered
questions.
Newton created the Method of Fluctions so that he could adequately explain
these mysteries. Today, known as Integral and Differential Calculus, this
invention is used throughout the technical and scientific world. Newton was
up against an unusual obstacle: the Inquisition and the Hierarchy behind it.
He kept his solutions to himself for another twenty years?, and only published
after spending a great deal of time deciding exactly how to phrase every word
so that he would literally escape torture and death. Examples…
With these analysis techniques and the fields of math and physics that flowed
from them out in the open, others would bravely expand on his work over the
next hundred or so ?? years, allowing a firmly rooted scientific and mathematical
underpinning for the technological explosion that followed in the nineteenth
and twentieth centuries. It is worth pondering the magnitude of Newton's gifts
to the world as they account for 99.999% of all physical behavior, while Einstein,
Plank, Heisinburg etc together offer you an understanding of only part of
remaining 0.0001%. Needless to say, in this discussion, based as it is in
the natural and real world, is entirely based upon Isaac Newton's comprehension
of the physical world.
REVIEW of Newtonian Mechanics, and Calculus.
The Scientific Method can be paraphrased as (1) hypothesis, (2) experimental
and/or theoretical testing of the hypothesis, and (3) writing a paper that
very few people can understand, much less question, so that your filtered
hypothesis appears to remain intact. If you are a pioneer, others will build
upon your "verified hypothesis" and at some point it will become
truth, or even the extension of truth that best not be challenged: scientific
dogma.
We should not be too hard on our fellow scientists, since their careers, their
reputations, their bread and butter and their steak and eggs, depend upon
their ability to walk that narrow ledge between established scientific dogma
and some precious new piece of the puzzle that does not fit into the wall
of dogma. This precisely describes the state of scientific inquiry at the
time of Newton and makes his willingness to shake the establishment all the
more remarkable. Today's scientists may not face death for their ideas, but
challenging the status quo remains a daunting task, and can often mark the
end of their careers.
Engineering, on the other hand, as it is based almost entirely on Newton's
discoveries, has the additional luxury of not having to precisely describe
why something works when it is sufficient to simply state that it does work.
Empiricism rules. Of course, if we are going to insist on numerical solutions
that mean something in the real world, we had better have some tricks up our
sleeves to tie up the loose ends between that which may be adequately described
by existing scientific knowledge, and that which may only be described by
interpolating or extrapolating experimental observations.
More >>>
Wood with horizontal shear, bulk shear, compression along the grain, across
the grain, bending, sudden loads, slow loads, MOE, modulus of rupture, USFS
tests, density,
Wood: Wanted, Dead or Alive. Differences. Useful behavior of living systems.
Bolster. Group protections. Geiger - Climate near the ground.
Finally: Trees stand up by Euler where Le/D is… and by experimental
observation by JB Johnson's formula wich provide a more accurate description
of experimental observations, typically where Le/D is …
Theory of Elasticity
Hyperelastic stretching (nuclear bombs)
Combination of Compression and Bending: Codes don't look at the case where…
Metallurgy, Alchemy, treated wood, corrosion, compartmentalize, encapsulate,
Explain the Theory of Elasticity, Mohr's Circle, and how it follows that FEA
works and how combined stresses mean anything. And back to experimental observations.
Suggested solutions to mystrees. The micro load cell, the tension test calibrates
sail behavior, do some of them and publish??
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