Introduction

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10:32 Mechanical Design Relation

• +Manufacturing method

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15:14 Material Strength vs. Stress

• ${\sigma }_{\text{UTS}}$ and ${\sigma }_{\text{y}}$ are constant regardless of the dimensions and load
• However, stress varies with strain
• For a given material, strength is a property of this material, but stress on a part made of this material depends on the dimensions and load applied on this part

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25:41 Types of Loading

• Load perpendicular on cross-sectional area $\to$ Tension or Compression
• Load parallel to cross-sectional area $\to$ Shear or Bending
• Load twists/squeezes the part $\to$ Torsion

Where are Force, Moment, Torsion, and Torque from this map?

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30:37 Stress is the internal resistance of the material to the applied load

• Stress (the internal resistance of the material) varies according to the applied load and dimensions
• Material Strength is the maximum Stress a material can sustain (before plastic deformation $\to$ Yield Strength | before failure $\to$ Ultimate Tensile Strength)

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37:18 The choice of load to be applied on the material depends on the application (what you want to do with the material), which means designing for a certain Material Strength

• Design $\to$ Before Yield Strength
• Extrusion $\to$ After Yield Strength and Before Ultimate Tensile Strength
• Piercing & Blacking $\to$ After Ultimate Tensile Strength

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45:43 The effect of the applied external load on the material is deformation, which is known as Strain

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54:05 There are two types of Strain

• The main strain is the one along the direction of the applied load (this is called Longitudinal Strain)
• The strain perpendicular to the direction of the applied load is called Lateral Strain
• Poisson’s Ratio recognizes that the ratio between the lateral and longitudinal strain is constant for a given material

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01:05:54 Types of Stress

• Stress is still a general concept of internal resistance to the applied load, regardless of the type of that loading (force, torsion, moment)

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01:11:45 Types of Supports

• Supports provide Reactions equal and opposite to applied load to maintain the body in equilibrium in spite of applied load
• These reactions cause Stress in the material
• Without these reactions, the load would translate or rotate the material instead of inducing stress in it or deforming it

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