Testing of panel materials 1

[superiormaterials]

Hi everyone,

I am an engineer who knows little about structural engineering, but would love to learn more.

I have a question, hoping you can lead me to the right direction:

I have 80mm panels, coated with 4mm thick carbon fiber on each side, with styrofoam-type material in the middle. These panels are to be used in replacement of concrete walls for small houses.

I need to know whether I can use these panels as walls and roofs for small houses, as a replacement for concrete structures.

Is any preliminary analysis needed, or can I just use software in order to determine if it's sufficient to hold the required loads and resist cyclones, hurricanes and etc?

Can you briefly list the steps a structural engineer would need to take in order to determine if the proposed material is a viable replacement for construction?

I am pretty amateur in structural engineering so some input would be highly appreciated.

Thank you all

 

[Ron]

That's a tall order!

First of all, your proposed material is known as a "composite" material. In order to properly analyze its "global" structural capabilities, you have know a lot about the material and how it will respond to loading. Loading is not limited to direct structural loading....it will include environmental loading such as thermal changes (carbon fiber resins, like other epoxies, are susceptible to large coefficients of thermal expansion), wetting and drying, UV exposure, weathering in general, creep and probably a few others.

As you consider the individual properties of the composite, you'll also have to consider them when they act "compositely". As an example, if you intending to use this material as a primary structural wall panel, what happens when you cut a hole in it for installing windows or for running electrical lines/plumbing lines through it. Can it be cut and backwrapped in the field to accommodate these conditions or will each panel have to be manufactured with the "cuts" designed in and fabricated accordingly?

What about connections? How will you connect the panels to the foundation? How will you attach other items to the panels? A 4mm layer of carbon fiber can be very strong linearly, but is not sufficient to hold a screw against pull-out or pull-over resistance.

What about serviceability? How much will the panel deflect under loading? Will there be cladding on the face and if so, how will that be attached and can it withstand the deflection. An example would be stucco. It is a brittle material with low tolerance to substrate deflection.

What about delamination? Have you considered that the carbon fiber-to-foam core adhesion will be a key to composite action? Can this adhesion handle repetitive loads (wind, seismic) and environmental loads (thermal, wetting/drying)?

You have a lot of considerations here before using such a material in a building code mandated setting. Composites are a subset specialty of several engineering disciplines, not just structural.

Good luck.

 

[BAretired]

Ron is correct in saying that is a tall order. You could graduate with a degree in engineering and still know nothing about the type of panels you are describing but you would certainly know something about concrete, timber and structural steel and you would know how to analyze a variety of simple structures.

Offhand, I would say that styrofoam panels covered with 4mm of carbon fiber would not be a suitable replacement for concrete panels, but I don't know the properties of your panel. The panels may be well suited to non-structural applications.

Your panel must be tested in a lab in order to determine its flexural strength, compressive strength, shear strength, elastic modulus and fire rating. Only then can you determine where and how it can be used structurally in a building.



BA

 

[superiormaterials]

Thank you Ron and BAretired for your reply.

Pardon me, it isn't carbon fibre i'm asking about, my mistake.

I got the properties for the wall panels if you would like to have a look, including testing results:

http://compositepanelbuildingsystem...-wall-panels/c-sip-wall-panel-specifications/

With the properties of both materials and testing based on international standards, how does a supplier confirm their product as structurally stable?

Do they use software in order to simulate weather and load conditions to determine its stability, or do they calculate the max potential loading the structure manually (eg, by hand) and determine whether the structure will safely resist the required conditions?

Do you think this material would be safe to use as the wall and roof slab for a small cabin? Eg 100m2 or 1000sq feet.

Thanks again.

 

[dhengr]

Superiormaterials:
The problem you are looking at is generally not a home/garage, DIY’er., project. It normally involves considerable engineering judgement and experience, knowledge of mechanical properties of the various basic materials, and then a good understanding of how the basic materials interact with each other. This is not something that a non-engineer would normally tackle without considerable help from others far more experienced in engineering and manufacturing methods. A regular panel manufacturer would spend some considerable time developing a product like this, with much product and basic materials knowledge going into the project. Then, they would do considerable load testing and environmental testing to determine fitness for service and life expectancy. This isn’t something you are going to master with a few posts on E-Tips, even though we have some pretty smart members here, always willing to give some limited help on engineering problems. You might do better to find a Uni. which offers a degree in Materials Science, Composites, Structural Engineering and testing, then you would at least be sorta ready to go to work for some company that designs and builds these kinds of product. Otherwise, you’re kinda playin at being an engineer and product maker, in your garage. What kind of engineer are you, and what is your educational and experience background in these kinds of structural products?

Then, you throw us a real curve ball...., this is a well developed product, by an experienced SIP (Structural Insulated Panels) manufacturer. Why not read their literature, and the various standards which it has been tested to or manufactured to? Then investigate their reputation as a building product manufacturer and supplier. That’s a vastly different question than what you seemed to be asking in the first place, and the way you asked the question doesn’t show much engineering savvy. The product is not necessarily intended to replace only concrete walls and slabs, although it might in some cases (foundation walls). My first para., above, was in answer to your OP, and I thought, why bother, Ron’s already said it in slightly different words. Then, I saw your 29MAY17 attachment, and had just run across an article on this very product in the May17 issue of “Composites World” mag. This is an acceptable means of building, when done right, by the right builder. And, they can mess it up when they don’t know what they are doing. I’ve not used these exact products, but I have no doubt that they can be made to work for light construction.

 

[BAretired]

Do you think this material would be safe to use as the wall and roof slab for a small cabin? Eg 100m2 or 1000sq feet.

It appears that the material would be suitable for walls in small residential buildings. It is not intended to act as a roof slab and would not be suitable for that purpose.

BA