Tham khảo tài liệu 'bruhn - analysis and design of flight vehicles structures episode 3 part 4', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | ANALYSIS AND DESIGN OF FLIGHT VEHICLE STRUCTURES Table Column Formulas for Round steel Tubes Material Ftu ksi Fty ksi Fco ksi Short columns a Transi-tional c L o Long columns b Local failure Column formula b Basic equation 1025 55 36 36 36 000-1. 172 L p 3 . 122 286 X 107 L p 3 . 286 X 10a L p . d 4130 Heat-treated e alloy 95 75 6 79 500-51. 9 Lf p 1 . C4. 4 91 d steel Heat-treated alloy 125 103 113 113 L p 3. C4. 3 73 286 X 107 L p a . d steel Heat-treated alloy 150 132 145 145 000-18. 36 L p a. 83 286 X 10a L7p 8 . steel 180 163 179 179 000-27. 95 L p 3 . 56 286 X 10V L7p a . d a Equation may be used in the short column range ư E Is replaced by Et obtained from the combined stressstrain curvesfor the material. b L p L pi ci L p shall not exceed 150 without spectfic authority from the procuring or certtficating agency. c Transitional L p is that above which columns are long and below which they are short. These are approximate values. d Not necessary to investigate for local Instability when D t 50. e This value is applicable when the material is furnished in condition N MIL-T-6736 but the yield strength is reduced when normalized subsequent to welding to 60 ksi. are given In Tables and . Table Column Formulas for Magnesium-Alloy Extruded open Shapesa GENERAL FORMULA K FCy a c L 4j Stress values are in kai Alloy K a m Max. Fc MIA 180 1 2 90 Fey AZ31B AZ61A AZ80A. . 2 900 1 4 Fey AZ80A-T6 ZK60A-T5 . . 3 300 1 4 Fey a Formulas given above are for members that do not fail by local buckling. Table Column Formula for AZ31B-H24 Magneslum-AHoy Sheet ns - J105 Fcy L 0 a 4n E Max. Fc FCy Short Column Equations for other Materials. For other metals for which short column equations are not available the use of Euler s equation using the tangent modulus Et can be used eq. . Refer to Chapter C2 for information on how to construct column strength curves using this equation. C4. 8 Column .
