Why can’t we all just get along?

There is a long running tribalism in the Engineering world - you are either a ‘composites person’ or a ‘metals person’.

The composites people try and justify making everything in composites, and the metals people want to make everything in metal, even when it does not make much engineering sense.

Now if the current political climate is anything to go by, I have immediately alienated 80% of the people reading this who want to stick to their tribal ideologies, and that’s ok because I wasn’t going to change their minds anyway.

If you are still reading then you are probably one of the people who consider that maybe the world is more nuanced than that, and perhaps we should seek a world in which composites and metals live in harmony doing the jobs they do best.

Enough with the political analogy!

The problem with composites and metals is that they see the world in different ways.

Composites like to be optimised for a particular situation, and they excel in a predictable world which does not throw them curveballs. They are amazingly efficient when optimised, and the more consistent and predictable the loading they will experience is, the more optimised you can make them. Composites are the specialist of the materials world.

Metals on the other hand tend to be all-rounders. They do not mind a world which is a bit unpredictable, because they are pretty good at handling loads coming through them from all directions. They cannot be so highly optimised for a particular load case as a composite, but they are much better at handling big loads coming from all angles. Metals are the multi-tasker of the materials world.

Engineers do recognise this of course. Structures tend to use composites for large areas with loading predominantly in a single direction (e.g. wing skins) and metals for parts which see loading from many different angles in a multitude of load cases (e.g. brackets & fittings).

The problem comes when these metal and composite parts need to work together. In a world of such Engineering tribalism, where departments are often divided upon these territorial lines, it is perhaps not surprising that the interface between these things can be a bit clumsy.

Often the answer is to drill some holes in both parts and bolt them together. This guarantees that the two tribes need to have the absolute minimum interaction possible. Those poor fasteners are like mediators, trying desperately to hold it all together.

But it is not very efficient.

Composites do not like having holes drilled in them. They take it out on the cutting tools which are super expensive and wear out fast. They respond differently to drilling than the metal parts, so you need special techniques to drill through both and end up with the right size hole. Composites often need to be thickened up locally to handle the loads being introduced, but you cannot just have a sharp step down at the edge, so you have a gradual ramp down in thickness away from the joint, adding lots of weight.

It seems like in the battle for how to join metal parts to composite parts, maybe the metal tribe won the battle, because drilling holes is fine for them, but it is a nightmare for the composites tribe.

But the metal tribe need not win the war. In fact, why does it even need to be a war?

If only we could bridge the differences and find a more suitable compromise for these two material tribes to work together.

This is why the Hyperjoint was invented. It was an attempt to find a better way, and it works.

Manufacturing of metal parts using Additive Manufacturing enables us to texture the interfacing surface, providing a forest of little arrowheads which nestle in amongst the composite fibres. It helps the metal part to introduce load into the composite part in a way that is considerate of its strengths and weaknesses. And when you work together, you are stronger.

A bit like society...