INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Jobs

Shock analysis using Solidworks simulation

Shock analysis using Solidworks simulation

(OP)
Hello,

I am doing a Shock analysis of Pump using Solidworks simulation. attached are the shock load input(Full sine wave) and Max stress plot at a node. My doubt is the peak load(+) is at 0.01 secs but the max stress is at 0.02 secs at which the amplitude is zero. Is that correct?

Is there any relation or formula saying max stress should be at the time of peak load? Pls clarify.

RE: Shock analysis using Solidworks simulation

I have not opened the attachment. The peak stress will occur at peak strain. Strain waves take time to travel through the structure. The speed at which they travel is not simple, in general, but is strongly related to the modes which have been excited.

Cheers

Greg Locock


New here? Try reading these, they might help FAQ731-376: Eng-Tips.com Forum Policies http://eng-tips.com/market.cfm?

RE: Shock analysis using Solidworks simulation

(OP)
Hi GregLocock, thanks for the response.

as you said, peak stress occurs at peak strain which is,in my case, exactly at 0.02 secs. So is there any relation between this stress/strain w.r.t time? why not at some other time say 0.035 secs? I googled to find, but didnt get anything related.

RE: Shock analysis using Solidworks simulation

Greg answered your question already: "Strain waves take time to travel through the structure. The speed at which they travel is not simple, in general, but is strongly related to the modes which have been excited."

TTFN (ta ta for now)
I can do absolutely anything. I'm an expert! https://www.youtube.com/watch?v=BKorP55Aqvg
FAQ731-376: Eng-Tips.com Forum Policies forum1529: Translation Assistance for Engineers Entire Forum list http://www.eng-tips.com/forumlist.cfm

RE: Shock analysis using Solidworks simulation

Peak stress lags peak acceleration, sounds ok.

I'd be more worried if it were the other way 'round.

RE: Shock analysis using Solidworks simulation

Exactly, root E/rho is the speed of compression waves (axial waves). Most modes in structures are bending waves, which are much slower.

It would be interesting, and possible, to look at real world test data on this. The concepts are loosely associated with structural intensity, analogous to acoustic intensity. The non quadrature part of the energy in the mode is actual energy being transmitted.

Cheers

Greg Locock


New here? Try reading these, they might help FAQ731-376: Eng-Tips.com Forum Policies http://eng-tips.com/market.cfm?

RE: Shock analysis using Solidworks simulation

There is, since there's sheer kinetic energy or explosives. I was specifically referring to EFPs, as there was, and still is, to some degree, some uncertainty as to whether penetration by EFPs, particularly the pointy ones, is due to melting of the armor or some other mechanism. There's still information out there that states that EFP projectiles are essentially like hot lances, but it's unclear whether there's sufficient thermal mass to melt armor, particularly if it's composite armor.

TTFN (ta ta for now)
I can do absolutely anything. I'm an expert! https://www.youtube.com/watch?v=BKorP55Aqvg
FAQ731-376: Eng-Tips.com Forum Policies forum1529: Translation Assistance for Engineers Entire Forum list http://www.eng-tips.com/forumlist.cfm

RE: Shock analysis using Solidworks simulation

AP shells have a hardened cap that in theory remains in one piece during the entire penetration. Not surprisingly the poor control over heat treatment in WW1 caused a significant number of shells to shatter on impact. Nonetheless Campbell's book includes many photos of holes punched neatly through 12" plate.

here's the sort of thing

http://www.kbismarck.org/forum/viewtopic.php?t=162

Cheers

Greg Locock


New here? Try reading these, they might help FAQ731-376: Eng-Tips.com Forum Policies http://eng-tips.com/market.cfm?

RE: Shock analysis using Solidworks simulation

Sure, but you have to compare that against same AP shell just pushing on the armor. Under those conditions the armor will distort and possibly fracture before you could get any sort of hole in it. Moreover, some EFPs use copper, which is hard, particularly since it's work-hardened in the process of forming the projectile, but not harder than Chobham armor, and yet, there are M1A1s with holes, but not necessarily through holes, in their armor from improvised EFPs.

TTFN (ta ta for now)
I can do absolutely anything. I'm an expert! https://www.youtube.com/watch?v=BKorP55Aqvg
FAQ731-376: Eng-Tips.com Forum Policies forum1529: Translation Assistance for Engineers Entire Forum list http://www.eng-tips.com/forumlist.cfm

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources


Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close