Imagine your esk8 floating in the air with arrows poking at it.

Weird, but it’s exactly what’s needed to calculate the loads.

 

Make sure to catch the full picture, before diving into the loads.

And, while you are here, hit subscribe at the upper right corner.

 

Loads are nothing more than forces and moments which act throughout your part or structure. To calculate those, we need to know the supports and the reactions.

 

Supports

Supports are the places where your thingy (part/structure) meets the world.
These can be of two kinds – those which support forces - simple support.
And those which support forces and moments - clamped.

 

Esk8 deck is connected to the trucks, which are in turn supported by the wheels. Wheels can roll and can’t hold moments – this is simple support.

My binding design is held by the aluminum profile and the bolts. This resists the applied loads and stays in place – this one is clamped.

Simply supported and clamped
Simply supported and clamped

Reactions

These are the forces/moments which develop at the supports.

The cool thing about it, is they must balance the external loads exactly.

 

For simple support we must find the reaction force.

For clamped support we need to find the force and the moment.

 

Sounds complicated?
Let’s see if the following pictures clarify this a little bit:

Just an external load on the structure
Just an external load on the structure
Reactions at clamped support
Reactions at clamped support
Calculated reactions - fully balance the external load
Calculated reactions - fully balance the external load

Let's do another one, this time simply supported:

frame11
Load and the reactions from the ground
Load and the reactions from the ground
Calculated reactions
Calculated reactions

Ok, so now what?

Once the loads and the reactions are known, we just need to sum these up from left to right.

This is a simple task for Excel, or a piece of paper.

 

Here is the binding piece:

Force and Moment distribution along the binding piece
Force and Moment distribution along the binding piece

And the short deck:

Forces and moments through the deck
Forces and moments through the deck

So what?

The last two pictures are important.

If the forces and moments are known, you can design the structure to hold them.

 

Let's find out how next week.

Enjoy,
Dani

 

Like what you read?

Make sure to subscribe and get the next post in the series.

 

PS

I’m doing something new here.

A short series of posts dedicated to designing your own, as strong as you want, structures.

I’ll cover the basics, so you can do the rest.

Let me know what you think: dani@dosimplecarbon.com