Deflection of BeamDeflection of Beam

Pairat Tanpornprasert , Ph.D.Pairat Tanpornprasert , Ph.D.Niphon Wansophark Niphon Wansophark , Ph.D, Ph.D

Mechanical Engineering DepartmentMechanical Engineering DepartmentFaculty of EngineeringFaculty of Engineering

Chulalonkorn UniversityChulalonkorn University

IntroductionIntroduction

A beam is defined as a structural A beam is defined as a structural member which cross-sectional member which cross-sectional dimensions are relatively smaller dimensions are relatively smaller than its length than its length

A beam is subjected to loads A beam is subjected to loads perpendicular to its long dimensionperpendicular to its long dimension

Beam deflections are considered to Beam deflections are considered to be elastic deflectionsbe elastic deflections

Introduction (con’)Introduction (con’)

The design of beams is often based on deflection The design of beams is often based on deflection characteristics, rather than strengthcharacteristics, rather than strength

Beams are used in different kinds of construction Beams are used in different kinds of construction

- - Machine - Bridges - Airplanes - Automotives

- etc,- etc,

FramesFrames

MachineMachine

BridgeBridge

RoofRoof

AirplaneAirplane

RobotsRobots

                        

Intelligence and networking

MotivationMotivation The deflection of machine parts must also The deflection of machine parts must also

be kept below certain tolerances to allow be kept below certain tolerances to allow the machine to function properly the machine to function properly - Difficulties in parts assembly and - Difficulties in parts assembly and installationinstallation- Unbalance in rotating shaft- Unbalance in rotating shaft

Large deflection cause or create unstable Large deflection cause or create unstable structurestructure- Floor collapse- Floor collapse- Bridge collapse- Bridge collapse

Motivation (con’)Motivation (con’)

Precision machine needs rigid Precision machine needs rigid structurestructure

- Machine tool- Machine tool

- Robotics- Robotics

- Measuring Instrument- Measuring Instrument Allowable deflection of beams are Allowable deflection of beams are

often limitedoften limited Stresses are also limitedStresses are also limited

Mississippi River BridgeMississippi River Bridge

collapscollapseded on August 1, 2007 on August 1, 2007

Coordinate Measuring Machine Coordinate Measuring Machine (CMM)(CMM)

Robotics (High Rigidity)Robotics (High Rigidity)

Machine tool (High Rigidity)Machine tool (High Rigidity)