Engineering & Analysis Methods > Bolted Joints

BJSFM Single Shear Correction Factor & Bearing Allowable

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samoashworth:
Hi,  Can you recommend any single shear correction factors?  Previous threads have noted that the BJSFM method assumes double shear.

James:
There are some suggested correction factors in the HyperSizer help documentation:
http://hypersizer.com/help/#Failure/BJSFM/bjsfm-joint_factors.php%3FTocPath%3DFailure%2520Analysis%7CJoints%7CBolted%7C_____4

The joint eccentricity factor (single lap shear factor) is applied to correct the bending moments present in single shear joints which are not captured in a FEM joining two co-planner meshes. The baseline is a double lap shear joint with equal splice plates, Kj = 1.0. In this case, bending is virtually eliminated. Typical single shear factors for solid laminates are 0.7 < Kj < 0.8. For single lap shear joints joining two honeycomb panels, 0.9 < Kj < 1.0.

samoashworth:
One more question - during the BJSFM analysis I get a warning "warning: a/Diameter Ratio <4 (=3.00)".  I have based my a and b to be equal to 3d where my diameter is 4.5mm based on HyperSizer recommendations that finite width is typically 3d.

Is it acceptable for my a/Diameter ratio to be <4, i.e. is it acceptable for this warning to contradict the 3d finite width recommendations?

Thanks for your help in advance,
 :)

samoashworth:
Hi again. 
My single and double shear material data is in carpet plot form.  How could I enter a range of data so that I don't have to set a Stress: Bearing value in the "laminate allowables" tab for each of my laminates or single/double shear requirements?

I am currently running double and single shear analyses for multiple lay-ups and have to keep entering individual data. 
For example, one lay-up I have is at 53% ±45°, 10% 90°, 37% 0° so I enter a value, xxx into the Stress:Bearing laminate property area using the property method "Percent '45' Degree Fibers" by entering 53 and xxx into "Percent '45' Degree Fibers Value" and "Y Value?" respectively. 
I then need to analyse another lay up, this time at 60% ±45°, 20% 90°, 20% 0° so re-enter my data.
Is there a method you can suggest that allows quick analysis instead of changing individual values for each lay-up/type of bolted joint?
Thanks

James:
Carpet plots can be stored in HyperSizer for the laminate bearing allowables using the 'Polynomial' method. To derive the polynomial coefficients you can list the points in Excel and do a data regression analysis.

Here is an Excel help topic that has a simple example.
https://support.microsoft.com/en-us/kb/103839
See "CALCULATING A POLYNOMIAL CURVE"

-James

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