redeyerighley
Mechanical
Hi Guys,
This is my first eng-tips post, have had a read through all over and am enjoying the site - its great! So a big hi from South Africa!!!!
I am a mech eng but have no experience in composites and this is why the post....
I am looking to replace aluminium sheet metal in an impact resistant application in order to reduce mass. The item to be manufactured is a guard to take impact and prevent damage to components behind/below it.
Things to consider:
1. Impact resistance, this will take place many times and the guard should not fail.
2. Stiffness, the guard cannot be too far from the "item" due to space constraints and if the guard comes into contact with the "item" it will cause it to be damaged.
3. Ease of manufacture and cost: I am looking at a prototype in my personal capacity at the moment and would prefer relatively simple methods for manufacture.
I have done a fair bit of reading online, but as I said I have very little knowledge of composites to begin with; so far this is what I have come up with:
A sandwich structure to improve stiffness (is this a bad idea as it would be better to load a sandwich structure on an axis parallel to the plane of the "skins" and because it could compress the core material impacting on the performance????) I am considering this material: , any other suggestions? (I must admit I havent checked the cost of this material).
I would like to use a combination of Carbon and Aramid (Kevlar) materials to obtain both stiffness and impact reistance/toughness). Any thoughts on this and which materials to use?
Also, in terms of analysing this system: where would a good place be to start? The load that will be placed on the material will be on a variety of planes as the load can come from anywhere and the form of the guard is a complex 3D shape. The load will also be repeated and occur randomly. Also, I do not really know about where to begin with in terms of determining load (how do I measure the force due to impact?) - thus far I have just compared it to aluminium plate of 4mm thickness.
Finally, regarding mounting: The guard will be mounted using fasteners. Should the core be replaced in these sections using aluminium and then insulating the aluminium from the rest of the material to prevent galvanic corrosion (From what I have read this seems to be a good idea)? What is commonly done during the layup to achieve this?
Also, it says that these core materials are vacuum formed, has anyone got experience with doing this and how easy is it to achieve as opposed to vacuum forming of plastics? (I am looking at doing this to achieve the desired shape and then vacuum moulding the CF/Aramid to this form); I would look at doing this in a simple home setup vacuum forming system - any thoughts on this? Remember, the prototype will be built with cost constraints and an expensive manufacturing facility is not available.
Thanks in advance for any comments, advice and critisism. Also, I find this very interestiung and have had a look/read at the resources linked to on this forum, but if there are any more resources (especially regarding the layup and design of sandwich structures) it would be greatly appreciated.
This is my first eng-tips post, have had a read through all over and am enjoying the site - its great! So a big hi from South Africa!!!!
I am a mech eng but have no experience in composites and this is why the post....
I am looking to replace aluminium sheet metal in an impact resistant application in order to reduce mass. The item to be manufactured is a guard to take impact and prevent damage to components behind/below it.
Things to consider:
1. Impact resistance, this will take place many times and the guard should not fail.
2. Stiffness, the guard cannot be too far from the "item" due to space constraints and if the guard comes into contact with the "item" it will cause it to be damaged.
3. Ease of manufacture and cost: I am looking at a prototype in my personal capacity at the moment and would prefer relatively simple methods for manufacture.
I have done a fair bit of reading online, but as I said I have very little knowledge of composites to begin with; so far this is what I have come up with:
A sandwich structure to improve stiffness (is this a bad idea as it would be better to load a sandwich structure on an axis parallel to the plane of the "skins" and because it could compress the core material impacting on the performance????) I am considering this material: , any other suggestions? (I must admit I havent checked the cost of this material).
I would like to use a combination of Carbon and Aramid (Kevlar) materials to obtain both stiffness and impact reistance/toughness). Any thoughts on this and which materials to use?
Also, in terms of analysing this system: where would a good place be to start? The load that will be placed on the material will be on a variety of planes as the load can come from anywhere and the form of the guard is a complex 3D shape. The load will also be repeated and occur randomly. Also, I do not really know about where to begin with in terms of determining load (how do I measure the force due to impact?) - thus far I have just compared it to aluminium plate of 4mm thickness.
Finally, regarding mounting: The guard will be mounted using fasteners. Should the core be replaced in these sections using aluminium and then insulating the aluminium from the rest of the material to prevent galvanic corrosion (From what I have read this seems to be a good idea)? What is commonly done during the layup to achieve this?
Also, it says that these core materials are vacuum formed, has anyone got experience with doing this and how easy is it to achieve as opposed to vacuum forming of plastics? (I am looking at doing this to achieve the desired shape and then vacuum moulding the CF/Aramid to this form); I would look at doing this in a simple home setup vacuum forming system - any thoughts on this? Remember, the prototype will be built with cost constraints and an expensive manufacturing facility is not available.
Thanks in advance for any comments, advice and critisism. Also, I find this very interestiung and have had a look/read at the resources linked to on this forum, but if there are any more resources (especially regarding the layup and design of sandwich structures) it would be greatly appreciated.