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Calculating the “Hinge Boom” on the crane.

The angle from the cables to the new frame.

In the last post about the crane, “Using CAD in initial design – More work on the Popsicle Crane“, we determined all of the angles necessary to calculate the forces on all the beams and cables. In this post I will calculate all those forces

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Parachute Cord and Popsicle Crane Analysis

Face View of the Spring Scale

I spent some time analyzing the good the bad and the ugly of the popsicle crane boom test and there was some of all three. The main problem was the parachute cord stretching but I also did not have the angles I thought I did. First, the issue

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Test 2 of the Popsicle Crane Boom.

The crane boom.

Last night I tested the crane boom and the video has been published. The boom did a great job. The cables did not. I used paracord for the most stressed cables and it turns out that paracord is very elastic and I was not able to maintain the angle of the

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Why I built the Crane Boom Hinge the way I did.

The Plan for the Crane Butt.

Last night’s post, Popsicle Crane Update 3 was almost completely about construction of the crane boom hinge end (the “butt” end – a real term used by the crane industry.) I realized on the way to work today I did not talk about why I did what I

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Column Buckling – Length, Radius of Gyration, & Elasticity

Rubber Columns just don’t get it done.

It this post I am going to try to tie together all of the recent posts about the forces on beams, moment of inertia, and the stress-strain curve. This is an overview and not number crunching like the last post. Since we are dealing with unknowns with

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How Our Craft Stick Beams Resist Bending.

Four 2 X 3 Popsicle Columns

Cross section view of possible craft stick beams.

The problem we have with the craft sticks and bending is bending in the thin direction (axis). The answer I have come up with is stacking the sticks to get a wider beam in that direction as shown in

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How a beam resists bending. (Moment of Inertia)

Rubber Band simulation of a beam subjected to bending.

In the post “Stress, Strain and finding center“, I talked about simple compression and tension and how beam or column elongates under tension and shrinks under compression. In the elastic portion of the stress strain curve the beam is acting like a very very strong

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The centroid (center) of a beam.

Several posts ago I talked about finding the center of mass of an object. That procedure when applied to a flat surface (a plane) is used to locate the point called the centroid. The the plane is a flat plate made completely from a uniform material, the centroid is where a pin could be

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Stress, Strain and finding center.

Stress – Strain curve for metal.

This is the first of what will probably be three posts on the theory about the loading of beams and columns. This is why I am building the popsicle crane boom in the way I am doing it.

We have been tied up in details lately, so I

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The Popsicle Crane boom – Test 1.

Picture 1: All of the loads acting on the boom.

Over this long 3 day weekend I finally got the initial test tower completed and did some testing. In many ways it was my testing that failed and not the tower. There is a story often told in math class about the frog dying

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