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2E4: SOLIDS & STRUCTURES Lecture 10. Dr. Bidisha Ghosh Notes: http://www.tcd.ie/civileng/Staff/Bidisha.Ghosh/Solids & Structures. Moment curvature equation. A quick touch on bending before learning buckling! Moment at any section Moment-curvature equation :
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2E4: SOLIDS & STRUCTURESLecture 10 Dr. BidishaGhosh Notes: http://www.tcd.ie/civileng/Staff/Bidisha.Ghosh/Solids & Structures
Moment curvature equation A quick touch on bending before learning buckling! Moment at any section Moment-curvature equation: Buckling is an effect of combined compression & bending
Compression on A Slender Column From knowledge of bending, Solve this equation….. 1. 2. So,
Compression on A Slender Column For any buckling to happen the second condition has to be true and that means,
Compression on A Slender Column The strut will buckle at the lowest load, i.e. the EULER BUCKLING LOAD this formula is for a pin-ended column. Notes: 1. Radius of Gyration,
Slenderness Ratio, Effective Length Euler buckling load for pin-ended column, Hence, using radius of gyration, Slenderness ratio = (defined as) This critical load/buckling load is dependant on end conditions. It can be shown the general form of buckling load Effective length, (defined as) Effective Slenderness Ratio,
Classification of Columns CD is Euler curve showing behaviour of long columns For slenderness ratio less than 30, columns are called struts. They fail by yielding or crushing, generally not buckling. Euler formula should not be used for slenderness ratio <120
How things fail? Buckling
How things fail? Tension
How things fail? Compression
How things fail? Bending
How things fail? Shear
How things fail? Corrosion
How things fail? Fatigue
How things fail? Torsion