ERGO_BIOMECH_2010-szd - ERGONOMICS ERGONOMICS ASSOCIATE...

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Unformatted text preview: ERGONOMICS ERGONOMICS ASSOCIATE PROFESSOR DR. SITI ZAWIAH MD. DAWAL DEPT. OF ENGINEERING DESIGN AND MANUFACTURE UNIVERSITY OF MALAYA ERGONOMICS and BIOMECHANICS Copyright @ 2008 by ERGO Introduction Bio- life or way of life in Greek BioMechanics – branch of science – deals Mechanics with forces and effect of forces……. Three disciplines Three Mechanics of rigid body Mechanics of solid deformable bodies Fluid mechanics Mechanics- Forces and Motion Description and analysis of motion -kinematics Description Description and analysis of forces – kinetics Description and analysis of forces tend to cause Description motion -statics motion The Skeleton The General Functions Gives the body its basic shape and provides a strong , protective and supporting framework for all other systems of the body. of With regards to movement the bones of With the skeleton act as a levers operated by the skeletal muscles. the Mechanical Functions Mechanical At birth – 270 bones Adults – 206 bones 1)Acts as a supporting framework for the Acts rest of the body rest 2)Acts as a lever system – muscle 3)Protect certain organs Protect Anatomical Reference Position Anatomical Is the reference position or starting place Is when movement terms are defined. when Is an erect standing position with feet just Is slightly separated and the arms hanging relaxed at the sides with the palms of the hands facing forward. Anatomical Reference Planes Anatomical Median Plane or Sagittal plane – vertical Median plane that divide the body - left and right portions. portions. Coronal plane or Frontial plane – vertical Coronal plane perpendicular to median plane. ( anterior and posterior) Tranverse Plane – horizontal plane perpendicular to both median and coronal planes. Newton’s 1 Law of Motion Newton’s st A body which is at rest will remain at rest body unless some external force is applied to it and a body which is moving at a constant speed in a straight line will continue to do so unless some external force is applied to it. it. Newton’s 2 law of Motion Newton’s nd Force = mass x acceleration F=mxa The relationship between force, the The resulting motion of a body and the properties of the body itself. Newton’s 3 Law of motion Newton’s rd To every action force there is always opposed an To equal reaction force or equal The mutual action forces of two bodies upon each The other are always equal and oppositely directed. Moment of Force Moment = W x distance X1 Where W is the magnitude of the Where gravitational force e.g. weight of the boot and X1 is the perpendicular distance and Static Equilibrium There are two important aspects to the stability of equilibrium of the human body. Intrinsic stability – stability of the many segments of human body Extrinsic stability – the stability of the whole body with respect to its base support Example of stability of equilibrium Stable equilibrium Unstable equilibrium Neutral equilibrium Centre of Gravity The centre of gravity (C of G) of an object is the point at which all of the weight of the object may be considered to be concentrated and about which the object ( in theory) exactly balance. in The human body is not rigid and fixed and consequently there is no unique single centre of gravity for the whole body. centre However if we minimize motion of the However limbs and assume that our subject adopts what is referred to as standard anatomical position we can determine the effective centre of gravity for the whole body for that position. that Tutorial 1. How would you represent the line of 1. How gravity of the patient in each of the diagrams given. (approximate position) diagrams Copyright @ 2008 by ERGO Copyright @ 2008 by ERGO Tutorial 1 Tutorial Refer to the 1st Q comment on the stability of the subject in each position. of Machines and mechanism Rehabilitation machines are devices that have been developed to provide specific movements for limbs or joints or to provide specific resistance to muscle action Mechanism Mechanism such as lever used in machines to transform motion and /or force into a desired output. Lever Lever A llever is a rigid beam pivoted at a point ever known as the fulcrum. There are three classes of lever There - First order lever - Second order lever - Third order lever Inclined Plane Inclined plane is a good example of a method used since ancient times to raise heavy loads with a relatively small effort. heavy ...
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