Calculating Flexural Rigidity across span of guitar soundboard

[jellicorse]

Homework Statement

I am trying to calculate the flexural rigidity across the span of a guitar soundboard.

The soundboard is comprised of a number of struts, the shape of which can be approximated to a triangular section sitting on a rectangular section. This makes for straightforward calculation of the second moment of area.

Diagrams

I can see how to calculate the flexural rigidity of each soundboard-brace section: by finding the overall second moment of area of the section (using parallel axis theorem) and then multiplying this by the Young's Modulus (E). (In this case, a standard value for the material in question - Spruce at 10GPa).

What I can not see how to do is to find the overall flexural rigidity across a span of the soundboard.

I'd be very grateful if anyone could tell me how to approach this.

Homework Equations

Parallel Axis Theorem:
$$I_{AB} = I_C + l^2 A$$

$$Flexural Rigidity = EI$$

 

[SteamKing]

Sorry, right clicking doesn't show any images.

 

[jellicorse]

I think you have to select "show image in new tab" and it should work...

 

[SteamKing]

Sorry, t'aint nothin' there to click on.

Have you tried to contact a moderator about helping you to attach an image file?

 

[jellicorse]

Oh, cheers for letting me know! I'll see if I can contact a moderator...

 

[Astronuc]

I changed the [ IMG ] tags to [ url ] tags because it's a url rather than an image link.

The links now seem to work.

 

[jellicorse]

Thanks a lot Astronuc. I'll bear that in mind for future posts.