# Calculating impact resistance of a silicone wafer

1. Jan 25, 2016

### pmd

Wondering the best way to go about calculating the ability of a silicone wafer to withstand impact. Wanting to possibly use a small pc as a fracture barrier to indicate that a part was dropped and may potentially be damaged. Need it to handle 20G. Alternative mat'l suggestions would be appreciated.

2. Jan 26, 2016

### Nidum

I don't entirely understand the question - is this a wafer as in chip manufacture or just a sliver that you want to use for damage detection in a piece of equipment ?

Either way probably need to detect accelerations in three axes .

For general equipment an accelerometer system and recorder will supply all the information needed . You can buy packaged devices quite cheaply .

To design something yourself have a look at micromechanical systems and microaccelerometers . Etched in for chip wafers and some of the same ideas on larger scale for equipment . Set up to actually break for a one time detection or record the output for later analysis .

3. Jan 26, 2016

### pmd

Nidum, thanks for your reply. I am not looking to record any data. I am trying find a thin, brittle material that can be used in a manner that should it be dropped, will break when the impact exceeds a predetermined level. Much like the impact sensors found on wooden crates for shipping. If the crate gets dropped accidently, the sensor 'breaks' indicating that a certain force has been exceeded. Because the parts I want to protect are much lighter, I was thinking of using silicone wafer material or something equally brittle.

4. Jan 26, 2016

### Nidum

Glass is what is commonly used . Microscope slide sort of thickness . Cantilever with a weight at one end is probably easiest configuration .

Breaking load for cantilever can be estimated using standard calculations . Breaking load for real components will probably show some variation around the calculated figure .

5. Jan 26, 2016

### pmd

Thanks again. The thickness of a glass slide would be too thick that is why I was thinking silica wafer, it can be made very thin and varied to meet different loads. Because of other requirements, I will need to calculate a beam fixed at both ends rather than a simple cantilever perhaps find a thin rod of glass and start there. Appreciate the quick responses

6. Jan 26, 2016

### Nidum

Rod of glass is good - they come in many sizes .