I've used the 100G load factor for vibrations as well. There is a chart out there (Miner's?) that shows load factor vs. weight for dynamic loading. 100G's corresponds to equipment between 1 and 5 pounds. The load factor reduces linearly as the weight is increased.
This was only used for...
This is probably an in-house Raytheon Document (RAC - Raytheon Aircraft Company) similar to the Boeing Design Manuals (BDM's) 6000 Series. These documents show analysis methods that are approved and able to be referenced in certification documentation.
Unless you know someone who has worked at...
Hi Drkwing,
What specifically is your question? After looking at the deflection equation, little 'e' should be capital 'E' for the material modulus of elasticity. Also, P1 is not defined, but appears to be P1=Pcos(theta).
The strength equation is nothing more than flat plate bending at the...
The "14" is the bolt diameter in 32nd's. Therefore, the diameter is 7/16. The "24" is the grip length in 16th's. Therefore, the grip is 1.5 inches. I don't remember the significance of the "M", either.
Hombre
If you do not have access to the aircraft technical manuals such as SRM, MM, etc., Jane's All the World's Aircraft is an invaluable source for this type of information.
Hombre
If you joggle an internal repair doubler up and over a stringer and pick up the existing stringer fasteners, are these fasteners ineffective?
Bruhn discusses joggled members, i.e. angles, and says a general rule of thumb is not to allow any axial load across the joggle. The required balancing...
Just thought I would get my two cents worth in... we use flat fail safe straps on the upper chord of many different types of beams to carry the compression loads. I do not believe crippling applies in this case. Therefore, the allowable is the lower of Fcy or Fir.
Hombre
You might check to make sure that you have not inadvertently modeled your constraints in a different group or layer than the ones you are currently displaying.
Also, check to make sure that the constraints are included in the current load set that you are displaying.
This applies to displaying...
He is saying that the force output from NASTRAN for 2D elements is force per unit length (lbs/in for example). Therefore, you need to multiply the elemental force by the element length.
Hombre
jsboy,
The ELFORCE (or FORCE) card generates the nodal forces at the four corners of the 2 dimensional element and/or at the center of the element.
If CENTER is specified, only the force at the center is output which is the average of the nodal forces at the corners of the element...
Alex,
In regards to 2), it may be necessary to include a portion of the web to show the cap good. For instance, a very high compression load.
In this case it is justifiable to include an effective width of web based on the crippling allowable with one end fixed and one end free.
For example...
Good point... however, the use of cards and decks bring organization to the "lines" of code.
It would be very difficult to debug lines of code (which are nothing more than numbers in most cases)! Therefore, it is much easier (for my brain, anyway) to think of all the bulk data entries as cards...
Some clarification is needed... are you wanting the area moments of inertia for stiffness calculations or the mass moments of inertia for structural dynamics calcs?
Area moments may be calculated as outlined in Bruhn's Analysis and Design of Flight Vehicle Structures. Essentially, the area and...
Grant,
Look in Chapter 8 of MIL-HDBK-5 under threaded fasteners. The shear and tension allowables are based on the shear and tensile stress of the fastener, respectively.
For example, the AN3 bolts are 95 ksi shear and 125 ksi tension. Therefore, the allowable shear load is 2690 lbs. and the...
