Ch 1. Stress and Strain Multimedia Engineering Mechanics NormalStress Shear andBearing Stress NormalStrain Hooke'sLaw ThermalEffects IndeterminateStructures
 Chapter 1. Stress/Strain 2. Torsion 3. Beam Shr/Moment 4. Beam Stresses 5. Beam Deflections 6. Beam-Advanced 7. Stress Analysis 8. Strain Analysis 9. Columns Appendix Basic Math Units Basic Equations Sections Material Properties Structural Shapes Beam Equations Search eBooks Dynamics Statics Mechanics Fluids Thermodynamics Math Author(s): Kurt Gramoll ©Kurt Gramoll

 CASE STUDY INTRODUCTION Introduction Suspended shelf Dave needed more storage for his school books and clothes, but he did not want to use any floor space. He thought that a hanging shelf would solve the problem to store 6 book boxes and 6 clothes boxes, weighing 45 lb and 20 lb per box, respectively. To save money, he decided to use wood for both the shelf and the hanging rods. What is known: Each box is 1-foot square on its base. The shelf board weigts 35 lbs. The rod material is Douglas Fir. Rods are assumed to be circular. To be safe, a factor of safety of 4 is applied. Wood rods are available in increments of 1/16". There are a total of 4 rods. Question What diameter size rod is needed for the hanging shelf? Approach Using static equilibrium equations, find load in each rod. Apply factor of safety. Calculate the needed cross-sectional area, A based on the the allowable stress of Douglas Fir (see appendix for allowable stress).

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