Temperature and its affect on Plastics
Hello All.
I have the understanding that plastics, such as Nylon, will become more flexible and "weaker" (low tensile strength) with higher temperatures. In turn, they become more brittle and stronger (high tensile strength) with lower temperatures.
I believe this also applies to their compressive strengths, correct?
If we were to mount a nylon part to "something" using a bolt, which material property of the nylon should we most concern ourselves with?
My initial thought is that you would determine the axial force applied by the bolt and then calculate the stress of the "affected area" (the area of plastic underneath the bolt's head). You would then compare this stress to the compressive strength of the material, correct? Assuming you are below the compressive strength, one would think you are in good shape.
Now, lets take this same part and assemble it while it is very cold outside. The chances are that the part will crack during assembly due to being very brittle. By "chances" I mean I have seen this happen. This seems to go against my approach/theory above because the compressive strength of the material should be higher. How can one account for brittleness?
Thanks for your help.