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2E4: SOLIDS & STRUCTURES Lecture 3. Dr. Bidisha Ghosh Notes: http://www.tcd.ie/civileng/Staff/Bidisha.Ghosh/Solids & Structures. Tasks to complete before tutorial. Check if you understand force equilibrium and stress: Concept checkpoints M1.2 Normal Stress Basic Problems in mecmovies ,
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2E4: SOLIDS & STRUCTURESLecture 3 Dr. BidishaGhosh Notes: http://www.tcd.ie/civileng/Staff/Bidisha.Ghosh/Solids & Structures
Tasks to complete before tutorial Check if you understand force equilibrium and stress: Concept checkpoints M1.2 Normal Stress Basic Problems in mecmovies, http://web.mst.edu/~mecmovie/ Try to get all four problems right!
Stress: Types Normal Stress: Tension, Compression. Stress which acts normal to the direction of the surface. Shear Stress: A shear stress is produced whenever the applied forces cause one section of the to slide past the adjacent section.
Natural examples Failure in tension of the lateral side with the ankle Cliffs of Moher are s shear cliffs
Examples from Mecmovies: Normal and bearing stress are axial stresses. Shear stress occurs when a cross-section inside the pin experiences the gusset and the steel plate moving in two opposite directions.
Double shear Quick example on double shear Clevis bracket Clevis mounts Clevis pins It may look like this brake link after assembly!
What happens when load is applied? FBD of the pin Take the example of the clevis and bracket. The pin connection them is under a condition of double shear From equilibrium, force acting along the plane, v = p/2 Shear stress occurs to an area parallel to applied load.
Bearing Stress In the clevis bracket diagram, the pin creates stresses in members connecting them along the bearing area or surface of contact. Considering equilibrium, the stress is, Bearing stress is a special type of normal stress that occurs on the surface between two separate interacting members. It is assumed that the area of contact is the ‘projected contact area’ rather than the actual area.
Deformation due to axial force Axial force How much does it deform due to the application of the force along the axis? What is δ? • Strain • Stress • Hooke’s Law
Strain Another quick example from Mecmovies: