Understanding Beam Deflection in Double Cantilever Beams

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SUMMARY

In a double cantilever beam fixed at both ends, deflection behavior is influenced by geometric properties. Specifically, deflection increases with length due to increased bending moment, while it decreases with increased width and thickness due to the increased moment of inertia (I). The relationship between deflection and these dimensions is crucial for understanding beam mechanics in structural engineering.

PREREQUISITES
  • Understanding of beam mechanics
  • Familiarity with the concept of moment of inertia (I)
  • Knowledge of bending stress and deflection principles
  • Basic grasp of fixed-end beam boundary conditions
NEXT STEPS
  • Research the derivation of the beam deflection formula
  • Study the impact of moment of inertia on beam performance
  • Explore different boundary conditions and their effects on deflection
  • Investigate materials with varying elastic moduli and their influence on beam behavior
USEFUL FOR

Structural engineers, mechanical engineers, and students studying mechanics of materials will benefit from this discussion, particularly those focusing on beam design and analysis.

Tammy....
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Homework Statement



Can someone please tell me why in a double cantilever beam (fixed at both ends) the deflection increases when the length increases, the defelction decreases when the width increases and the deflection decreases when the thickness increases. I don't want to no why it does these in relation to the formula... just the physics part of it... thanx

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The Attempt at a Solution

 
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Tammy... said:

Homework Statement



Can someone please tell me why in a double cantilever beam (fixed at both ends) the deflection increases when the length increases, the defelction decreases when the width increases and the deflection decreases when the thickness increases. I don't want to no why it does these in relation to the formula... just the physics part of it... thanx
Tammy, I'm not sure what you mean by the 'physics' part of it; for a given load and end conditions, the deflection of any beam will increase when its length increases or when its width or depth (its area moment of inertia) decreases, per the deflection formula which is a function of load, boundary conditions, material elasticity, and the geometric properties of the beam. Are you looking for the math behind the physics? If this is a homework question, can you be a bit more specific and show some attempt at answering your own question?
 
Um... well its for an assignment... does the deflection decrease when the thickness and width increase becasue there is more area... like there is less stress because it is spread over a larger area which would cause less deflection?
 
Tammy... said:
Um... well its for an assignment... does the deflection decrease when the thickness and width increase becasue there is more area... like there is less stress because it is spread over a larger area which would cause less deflection?
That's pretty much correct, except, to be technically correct, you should substitute the word "area (A)'' with the term "moment of inertia (I)". In beams subjected to bending loads, both stress and deflection are functions of I, not A, although I and A are related.
 
oh ok... Thanks heaps for your help :)
 
what do you want an experiment in a laboratory ,or what?
 

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