FEA Von Mises vs Principal Stress
	Post Reply		Engineering Forum

Replies to this message

Re: FEA Von Mises vs Principal Stress
: FEA Von Mises vs Principal Stress -- promech	Post Reply	Top of thread	Engineering Forum

Posted by: swearingen ® 04/11/2005, 08:20:07 Author Profile eMail author Edit

You can have cases where the principal stresses are much higher than your von mises stresses. For instance, if you have near equal compression stresses in the prinicpal axes, the von mises stresses will be very low. Of course, if you have all equal compressive (or tensile) stresses, there is NO von mises stress...

Post Reply Tell a Friend (must be logged in) Alert Admin About Post

Where am I? Original Top of thread

| |

Re: FEA Von Mises vs Principal Stress
: Re: FEA Von Mises vs Principal Stress -- swearingen	Post Reply	Top of thread	Engineering Forum

Posted by: promech ® 04/11/2005, 08:45:12 Author Profile eMail author Edit

I see. Shape vs volume, right? In either case, which criterion should I use? It sounds like I should use max principal (even though the material is ductile). I stated my question in reverse. My von Mises stress is 1100 ksi, max principal is 700 ksi. I always thought that max principal is usually slightly higher. Modified by promech at Mon, Apr 11, 2005, 09:42:48

Post Reply Tell a Friend (must be logged in) Alert Admin About Post

Where am I? Original Top of thread

| |

Re: FEA Von Mises vs Principal Stress
: Re: FEA Von Mises vs Principal Stress -- promech	Post Reply	Top of thread	Engineering Forum

Posted by: swearingen ® 04/11/2005, 17:43:12 Author Profile eMail author Edit

The only way you can get von mises stresses greater than a max principal stress is when one or both of the other stresses is negative (compressive).

Post Reply Tell a Friend (must be logged in) Alert Admin About Post

Where am I? Original Top of thread

| |

: Re: FEA Von Mises
: Re: FEA Von Mises vs Principal Stress -- swearingen	Post Reply	Top of thread	Engineering Forum

Posted by: Engineer fahim ® 01/17/2010, 08:41:04 Author Profile eMail author Edit

Sir, I am using coventorware software for FEA analysis and i in my structure a part is behaving like a contilever beam ,a force of 300uN is applied at the tip of cantilever while other end of beam is fixed , it give me should give me tensile stesses at upper part and compressive at bottom side but it is giving me all tensile stresses at both side these are Von-mises stresses ,anybody who can give the reason for this kindly advise me?

Post Reply Tell a Friend (must be logged in) Alert Admin About Post

Where am I? Original Top of thread

|   |