Hello Everyone,
I'm reaching out for your input. My background is in fatigue life assessments, not materials engineering, so I'd value your thoughts on these statements:
Risks Associated with Machining Pre-Hardened PH13-8Mo:
Increased Residual Stresses:
Machining hardened material generates...
Hello, We need to design a fuse pin for a main landing gear. The goal is to achieve controlled shear failure to protect the aircraft. Our focus is on achieving a predictable failure in shear mode rather than tension or bending, as shear failure provides more controlled separation. To control the...
Hi Guys,
I recently noticed that there is significant difference between the predicted life with S/N curves shown in Figures 3.7.5.2.8(b)and 3.7.5.2.8(e) in MMPDS-09. Both of them are "for unnotched 7050-T7451 plate, long transverse direction, t/4 specimen locations". The second one is giving...
Hi Guys,
I recently noticed that there is significant difference between the predicted life with S/N curves shown in Figures 3.7.5.2.8(b)and 3.7.5.2.8(e) in MMPDS-09. Both of them are "for unnotched 7050-T7451 plate, long transverse direction, t/4 specimen locations". The second one is giving...
Hi Guys,
I noticed that on page A-7 of MMPDS-15, it is written that "S/N Curves are for a 50 percent probability of survival. We usually assume conservatively few fatigue penalization factors (such as anodizing + shot-peening, surface finish, ...). But, I would like to know if you apply another...
Hello,
We usually calculate Margins of Safety for compression spring as shown below:
Stress = 8 K Force Dmean / (pi*d^3) (Calculated Stress at max. operating deflection)
K = (4C-1)/(4C-4) + 0.615/C (Spring Stress Correction Factor)
C = Dmean / d (Spring Index)
M.S. = TDS Ftu / Stress...
Hi Guys,
I understood that if we have a Nastran Model of Aircraft then one way to find out stiffness of Aircraft Structure at attachment point to Landing Gears is using following cards:
ASET1 123 GRID1 GRID2 ... GRIDn (to have 3 x 3 stiffness matrix)
PARAM,EXTOUT,DMIGPCH
I also think that we...
Hello Guys,
If you have any experience with regard to Abaqus Unified FEA, please share it with me. FYI, I previously used Abaqus software and I had relatively a good experience for solving nonlinear contact problems. Now, I am wondering what is the capability of Abaqus Unified FEA? A general...
Hi,
I found the following paper interesting (FE-based fatigue analysis):
http://web.mscsoftware.com/support/library/conf/auto99/p00599.pdf
Now, I am looking for any reference for conventional stress analysis and Margin of Safety calculations of a wheel assembly (usage in landing gears of...
Hello,
As per our stress methodology, we consider rework allowance for stress analysis of lugs and pins, ...
But, I didn't find any reference that recommends rework allowance for fatigue analysis. I don't think that using rework allowance is recommended for fatigue analysis. Because, we...
Hi,
I would like to understand something about S-Basis in MMPDS-03 (because, my knowledge is limited in M & P engineering field).
In order to be complaint with the FAR regulation (item 23.613), one economical method is to select materials in MMPDS that contain both A- & B- Basis allowables...
Hi,
I would like to understand something about S-Basis in MMPDS-03 (my knowledge is limited in M & P engineering field).
In order to be complaint with the FAR regulation (item 23.613), one economical method is to select materials in MMPDS that contain both A- & B- Basis allowables that are...
Hello,
I would like to know what is the best approach for calculating the Ultimate Margin of Safety with FEM? I know that the nonlinear FEA is a better
approach, but it is not a cost-effective approach for 3D complex geometry models.
Consequently, I would like to employ the linear FEM with...
Hi,
I would like to know how to enable cells to be edited while leaving only some cells locked. I could do this task in excel 2000, but I have difficulty to perform this task in excel 2007. I appreciate your help.
Thanks,
A.A.Y.
Hi,
I am would like to know how can I get the stiffness matrix at some specific nodes of a Nastran Finite Element Model?
I believe that I should prepare a punch file with contents similar to the following lines:
DMIG KAAX 0 6 2 0 363
DMIG* KAAX...
Hi,
I have to perform a contact analysis between two parts as follows:
1) Pin (Male Part)
2) Socket (Female Part)
I would like to know if you have any experience with Nastran Gap Elements (sol 106) If so, could you please refer me to some examples?
I heard that I may save time by the above...
Hi,
I have to perform contact analysis between two parts as follows:
1) Pin (Male Part)
2) Socket (Female Part)
In order to do efficiently this simulation, I would like to use Nastran gap elements with sol 106.
Do you have any experience with this approach? If so, could you please refer me...
Hi,
I would like to know how can I define an Array in VB (Excel)?
I tried the following commands:
Dim myArray(5) As Integer
myArray = Array(12,3,13,64,245,75)
But, I got a compile error as follows:
Can't assign to array
Please let me know what is the proper way for...
Hi,
I would like to know how can I export the mesh made with GPS inside Catia V5 as a Nastran bdf input file?
I found that there is a product named GPN which belongs to the MSC.visualNastran and it complements CATIA V5 Analysis. But, we don't have this product. We have Catia V5 and MSC.Patran...
