Official Answer
Answer
Jireenyi dadhabbii hariiroo Goodman ykn ulaagaa Gerber fayyadamuun shallagama. 17-7PH CH900 tiif, dhiibbaan hojii $\sigma$ akka $\sigma = \frac{3 \pi P D_m}{4 b t^2 N^2}$tti shallagama. Dhiibbaan wal jijjiiru $\sigma_a = \frac{\sigma_{max} - \sigma_{min}}{2}$ fi dhiibbaan giddugaleessaa $\sigma_m = \frac{\sigma_{max} + \sigma_{min}}{2}$ daangaa obsa meeshaa $S_e$ fi cimina harkisaa dhumaa $S_u$ wajjin wal bira qabamee ilaalama. Qabxiin nageenyaa $n_f$ $\frac{1}{n_f} = \frac{\sigma_a}{S_e} + \frac{\sigma_m}{S_u}$ tiin kennama. Fayyadama marsaa olaanaa ($>10^6$ marsaa), dhiibbaan guddaan akka waliigalaatti bu’aa xumura fuulaafi dhiibbaa haftee adeemsa kooyilii irraa dhufuu danda’uuf herrega baasuuf humna harkisaa xiqqaa %50 caalu hin qabu.
