CMAA 74 - Local Flange Bending 1

[AllHandlesTaken]

In CMAA 74, paragraph 3.3.2.4.2 states:

The localized stresses due to local bending effects imposed by wheel loads calculated at points 0 and 1 are to be combined with the stresses due to the Case 2 loading specified in paragraph 3.3.2.3.2 of this specification.

However, it does not explicitly state how they should be combined.

Can anyone please shed some light on this.

Thanks

 

[ishvaaag]

My guess. It is a fatigue loading, hence one would be looking a safe von mises stress for the detail, number of cycles and range of stresses to be experienced. Essentially you would love to check the bent flange with a comparison stress against a safe value that meets fatigue concerns.

Also, wheel loading is exerted quite violently and then imparts more closer to twice than not the energy of deformation aspects considered in elastical deformation when the loads are laid slowly (always a tricky point to understand from energy of deformation, that integral under the straight line) and hence impact factors of say about 1.3 being considered for rail beams on the whole may be scarce for the local aspect of flange bending; one should consider if apply more impact there.

 

[CTW]

The attached doc should answer your question.

 

[AllHandlesTaken]

Thanks very much guys, von Mises it is.