PFATSMW

Format

(1)	(2)	(3)	(4)	(5)	(6)	(7)	(8)	(9)	(10)
PFATSMW	`ID`	`BRATIO`	`TREF`	`TREF_N`	`EVALDIS`

Field	Contents	SI Unit Example
`ID`	Each PFATSMW card must have a unique ID. This ID may be referenced from a FATDEF definition. No default (Integer > 0)
`BRATIO`	Critical bending ratio. Default = 0.5 (Real > 0.0)
`TREF`	Reference thickness for thickness effect consideration. 1 Default = 25.0 (Real > 0.0)
`TREF_N`	Exponent for the thickness effect consideration. 1 Default = 0.2 (Real ≥ 0.0)
`EVALDIS`	Evaluation distance in Joint Line method. 2 MINAVG (Default) Automatically determine the evaluation distance from the weld line for Stress calculation. Real The specified Real value is directly used as the evaluation distance from the Weld line for Stress calculation. blank (Real ≥ 0.0)

TREF is used to define the reference thickness for thickness effect consideration. If the thickness of a shell (T) is greater than the specified value (TREF), and the THCKCORR field on the FATPARM entry is set to YES, then the thickness effect is included by increasing the stress ( $σ_{i j}$ ) based on:(1)
$σ_{ij} = σ_{ij} {(\frac{T}{TREF})}^{TREF_N}$
The distance at which the stresses are evaluated for a particular weld is defined by EVALDIS. The stresses are actually evaluated at the element corners (based on STRESS output request or PARAM,CNST4FAT), and then the stresses are interpolated to the stress evaluation point (Figure 1) for each element. This stress is used in further fatigue calculations.

Figure 1.