STRESS CONCENTRATION FACTORS

[StressMan2506]

Does anyone know of a source for stress concentration factors for staggered rows of holes in a strip of finite width? Chart 4.3 of "Peterson's Stress Concentration Factors", 2nd edition, covers a single hole, and ESDU 85045 Fig. 5 covers two non-staggered rows.

Alternatively, can anyone suggest an adaptation of either of the above to cover the staggered case?

Thanks in anticipation.

 

[amorrison]

See thread2-120690

 

[ewh]

I am a designer, not a stress engineer, but I have been told numerous times by those that should know that staggered fasteners actually produce a weaker bond than non-staggered, due to the "zipper effect" (it's easier to pull out single rivets in a zig-zag line than double rivets in a straight line).

 

[StressMan2506]

Hi Amorrison4:

Thanks for your response but I don't have full internet access here at work so I cannot visit the sites referred to in Thread2-120690 at present; I will do it over the weekend at home. Can you tell me if finite width plates are covered? My problem concerns edge effects in such cases.

Regards,
Louis

 

[StressMan2506]

Hi ewh:

Thanks for your response, but I do need to address staggered holes because that is what I have been presented with. The joint is not a lap under tension, which is better without stagger.

Regards,
Louis

 

[Sparweb]

StressMan2506,

I posted the original query in thread2-120690. Here's the title of the paper I was asking about: "Stress in Perforated Panels", by JW Dally and AJ Durelli, Armour Research Foundation, published in Product Engineering March 1956.

The paper gives a method of finding stress concentration factors at the edges of holes in sheets in axial or bi-axial tension.

Since your case may involve shear instead, you might want another paper called "Experiments on Perforated Plates Subject to Shear", by R Narayanan and FY Chow, Journal of Strain Analysis, 1985. I haven't tried to use this paper, so I can't comment on its usefulness. Since their data comes from tests, I expect that it applies to finite plates.



Steven Fahey, CET

 

[StressMan2506]

Hi SparWeb:

I am particularly interested in stresses in the ligament between hole and edge of plate. Ideally, I would like to be able to assess cases where the holes are of differing sizes.

Regards,
Louis

(+44 7970 362573 cell/mobile)

 

[Sparweb]

Are you concerned by a case like that illustrated in Figure C13.6 of Bruhn? And only from a fatigue standpoint, or for its basic strength, too? There is another thread on the forum that explained the approach to "low edge-distance rivets". If that also interests you, I can dig it up.


Steven Fahey, CET

 

[StressMan2506]

Hi SparWeb:

The case I'm interested in is like Bruhn Fig C13.6, but with at least two rows of staggered holes. The case in Bruhn is covered by Chart 4.3 of "Peterson's Stress Concentration Factors", 2nd edition. ESDU 85045 Figs. 4 & 5 cover two non-staggered rows of holes the same size. Fig. 5 addresses stress at the hole edge at the ligament and Fig. 5 covers the point diametrically opposite.


Regards,
Louis

(+44 7970 362573 cell/mobile)

 

[Sparweb]

The paper I referenced above does cover staggered rows.

Steven Fahey, CET

 

[StressMan2506]

Hi SparWeb:

I wasn't able to find it yet...

 

[Sparweb]

http://sparweb.squarespace.com/

Steven Fahey, CET

 

[StressMan2506]

Thanks, Steven