Allowable for Thicknesses per MMPDS
Allowable for Thicknesses per MMPDS
(OP)
Hello,
I had a question on how to best properly apply material properties to a given piece of metal. As an example of the question: say that there is an aluminum 7075-T73 plate 4 inches thick that is machined down to form a pocket, so that all thicknesses are now 1 inch thick. Would one need to use mechanical properties for the 4 inch thickness range or could one use the 1 inch material properties for structural analysis?
I had a question on how to best properly apply material properties to a given piece of metal. As an example of the question: say that there is an aluminum 7075-T73 plate 4 inches thick that is machined down to form a pocket, so that all thicknesses are now 1 inch thick. Would one need to use mechanical properties for the 4 inch thickness range or could one use the 1 inch material properties for structural analysis?
RE: Allowable for Thicknesses per MMPDS
RE: Allowable for Thicknesses per MMPDS
If there is a de-rate on 4" plate, then you stuck with that regardless of how thin you machine it.
The properties are related to heat treatment response usually.
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P.E. Metallurgy, consulting work welcomed
RE: Allowable for Thicknesses per MMPDS
And agree, you must use properties for the starting plate or bar thickness prior to machining. And you must pay attention to L, LT, and ST direction strength differences.
RE: Allowable for Thicknesses per MMPDS
"Everyone is entitled to their own opinions, but they are not entitled to their own facts."
RE: Allowable for Thicknesses per MMPDS
MMPDS is an FAA/DoD authoritative source for aerospace-use metals [alloys/temper/spec] mechanical [and some physical] data. This manual was an evolution/replacement-for MIL-HDBK-5 Metallic Materials and Elements for Aerospace Vehicle Structures ... which was an evolution/replacement for ANC-5 Strength of Metal Aircraft Elements
ASMH => Aerospace Structural Metals Handbook is also an authoritative source for metal [alloys/temper/spec] mechanical and physical and [some] fabrication data.
DO NOT CONFUSE these FAA/DoD authoritative metals Handbooks with the informative ASM [American Society of Materials] Metals Handbooks
NOTE1. Another useful authoritative handbook for conventional [industrial] metal alloys, mechanical and physical properties, is...
CINDAS Structural Alloys Handbook.
Regards, Wil Taylor
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o We believe to be true what we prefer to be true. [Unknown]
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RE: Allowable for Thicknesses per MMPDS
The design properties are based on detailed statistical analysis.
This is why they are picky about starting size and orientation.
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P.E. Metallurgy, consulting work welcomed
RE: Allowable for Thicknesses per MMPDS
(I'm also aerospace deficient; my world is heavy metals)
"Everyone is entitled to their own opinions, but they are not entitled to their own facts."
RE: Allowable for Thicknesses per MMPDS
Doug