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Negative overstresses in material are missing
12-08-2019, 12:44 PM, (This post was last modified: 12-08-2019, 08:13 PM by shaswin.)
#1
Negative overstresses in material are missing
If one uses S-ALLOW in the SECTION input table it checks only the positive stresses of CSTRMAX output table.

But the negative stresses are somehow missed. If there is for example a high negative SFHT-M which is absolutely higher the the positive values PLE doesn't sees it as an overstress.

This can be the case with PE materials with low MRS values (S-ALLOW).

The legend of DF6.2 stays yellow when there is an overstress.
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14-08-2019, 11:04 AM,
#2
RE: Negative overstresses in material are missing
Thank you for reporting this. Could you attach an example project to illustrate your point?
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14-08-2019, 02:54 PM, (This post was last modified: 14-08-2019, 05:04 PM by Dr. J Foerster. Edit Reason: quoting of previous post is not necessary )
#3
RE: Negative overstresses in material are missing
See attached PLE project file

CSTRMAX input table:
[attachment=982]
In this case you are seeing that SFHT-M is higer the S-ALLOW. SXHT-M can also be higher theoratically.

SECTION input table:
[attachment=983]

Legend not updated:
[attachment=984]
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14-08-2019, 05:20 PM,
#4
RE: Negative overstresses in material are missing
Thank you, that clarifies the issue a bit.

No, there is no error in the program. As described in the help file (Data description of the SECTION table), "If specified in case of GENERAL stress calculations and exceeded in output table CSTRMAX, Von Misses stresses, a function warning will be given" (emphasis by me). So S-ALLOW is only used to check the MISES-M column, and in your case its maximum 5,83 is below the given limit of 6,50.
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15-08-2019, 09:56 PM, (This post was last modified: 16-08-2019, 07:40 AM by shaswin.)
#5
RE: Negative overstresses in material are missing
I thought SHOOP was also checked, but it should be strange then, it needs then different check stresses.
Is it possible then to extend the SECTION table that it also checks SX, SF, SHOOP and RDPLMAX/RMAXNEN, so with 4 extra optional columns.
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16-08-2019, 10:08 AM,
#6
RE: Negative overstresses in material are missing
I'll discuss your idea with my colleagues, maybe expanding the automatic checking functionality in "general" calculations might be a good idea.
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16-08-2019, 10:55 AM,
#7
RE: Negative overstresses in material are missing
Yeah, I also mean for the general calculations.
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