What is a frusta in stiffness for fastened memebrs?

[hihiip201]

HiAs I am reading through my textbook on the stiffness for two clamped members, As I am reading about the rotschers pressure cone , there is a sentence that say:

"in this book we use alpha(half apex angle) = 30 deg except in cases in which the material is insufficient to allow the frusta to exist" under WHAT condition will not the material allow the frusta to exist? I thought frustum is just the side of the member that we are looking at, how does the material affect geometry?English is my second language so it could be that there's some obvious meaning to these words that I'm not understanding, but I just feel like my textbook always pull out variables and technical terms without explaining what they are. I have spent more time googling than reading the book. anyway, I appreciate you guys' help.

 

[Navin A S]

The material affects the geometry because it determines the strength of the member, which then affects the size and shape of the frustum. If the material is not strong enough to support the shape of the frustum, then it will not be able to exist. For example, if the material has a very low strength, then the apex angle would have to be reduced to reduce the stress in the member and thus create a smaller frustum.