tailieunhanh - Standard Handbook of Machine Design P16

CHAPTER 13 STRENGTH UNDER DYNAMIC CONDITIONS Charles R. Mischke, ., RE. Professor Emeritus of Mechanical Engineering Iowa State University Ames, Iowa TESTING METHODS AND PRESENTATION OF RESULTS / SN DIAGRAM FOR SINUSOIDAL AND RANDOM LOADING / FATIGUE-STRENGTH MODIFICATION FACTORS / FLUCTUATING STRESS / COMPLICATED STRESS-VARIATION PATTERNS / STRENGTH AT CRITICAL LOCATIONS / COMBINED LOADING / SURFACE FATIGUE / REFERENCES / RECOMMENDED READING / NOMENCLATURE a A b B bhn BHN c C Cp d de D D1 E / fi Distance, exponent, constant Area, addition factor,. | _CHAPTER 13 STRENGTH UNDER DYNAMIC CONDITIONS Charles R. Mischke . . Professor Emeritus of Mechanical Engineering Iowa State University Ames Iowa TESTING METHODS AND PRESENTATION OF RESULTS SN DIAGRAM FOR SINUSOIDAL AND RANDOM LOADING FATIGUE-STRENGTH MODIFICATION FACTORS FLUCTUATING STRESS COMPLICATED STRESS-VARIATION PATTERNS STRENGTH AT CRITICAL LOCATIONS COMBINED LOADING SURFACE FATIGUE REFERENCES RECOMMENDED READING NOMENCLATURE a A b B bhn BHN Distance exponent constant Area addition factor Xz A Distance width exponent Zz2M Brinell hardness roller or pinion Brinell hardness cam or gear c C cp d de D D E f f Exponent Coefficient of variation Materials constant in rolling contact Difference in stress level diameter Equivalent diameter Damage per cycle or block of cycles Ideal critical diameter Young s modulus Fraction of mean ultimate tensile strength Fraction of life measure STANDARD HANDBOOK OF MACHINE DESIGN F Force S Significant force in contact fatigue h Depth Hb Brinell hardness I Second area moment k0 ka Marin surface condition modification factor kb Marin size modification factor kc kc Marin load modification factor kj kd Marin temperature modification factor kg ke Marin miscellaneous-effects modification factor K Load-life constant Ky Fatigue stress concentration factor K Geometric theoretical stress concentration factor Length log Base 10 logarithm In Natural logarithm L Life measure LN Lognormal m Strain-strengthening exponent revolutions ratio M Bending moment n n Design factor N Cycles Nf Cycles to failure N p cr Normal distribution with mean p and standard deviation J p Pressure P Axial load q Notch sensitivity r Notch radius slope of load line r Average peak-to-valley distance R Reliability Ra Average deviation from the mean Rrms Root-mean-squared deviation from the mean RA Fraction reduction in area Rq As-quenched .