UNIT I Introduction to Biomechanics: Biomechanics has participated in virtually every modern advance of medical sciences and technology.Itisatoolfordesignandinventionofdevicestoimprovethequalityoflife.The methodofbiomechanicsisthemethodofengineering,whichconsistsofobservation, experimentation, theorization, validation and application. It is the branch of science that explains the mechanics of life and living. From molecules to organisms, everything must obey the laws of mechanics. What is Biomechanics? Mechanics - Study of action of forces on particles and mechanical systems. Bio Prefix for life/living organisms Biomechanics - Applicationoftheprinciplesofmechanicstothestudyoflivingorganisms(i.e) application of mechanical principles to living organisms. Basic concepts in Biomechanics: The study of biomechanics ranges from the inner workings of a cellto the movement and developmentoflimbs,thevasculature,themechanicalpropertiesofsofttissueandbones.By applyinglawsandconceptsofphysics,biomechanicalmechanismsandstructurescanbe simulated and studied. This includes bioengineering, the research and analysis of the mechanics oflivingorganismsandapplicationofengineeringprinciplestoandfrombiologicalsystems. Researchandanalysiscanbecarriedforthonmultiplelevelsfromthemoleculeswherein biomaterials such as collagen and elastin are considered, up to tissue and organ level. Simple examples of biomechanics research include the investigation of forces that act on limbs,theaerodynamicsofbirdandinsectflight,thehydrodynamicsofswimminginfish, general locomotion in all forms of life from individual cells to whole organisms. The biomechanics of human beings is core part of Kinesiology. Plant biomechanics is application of biomechanical principles to plant and plant organs. Fieldswhichplayprominentroleinstudyofbiomechanicsare,thermodynamicsand continuummechanicsinAppliedMechanicsandfluidmechanicsandsolidmechanicsin mechanical engineering. Biomechanics as a sports science, Kinesiology where laws of mechanics and physics areappliedtounderstandhumanphysiologyandperformanceinathleticeventsthrough modeling, computer simulation, stimulation, gesticulation, mastication and measurement. Common methods used for analysis: Elements of mechanical engineering ( eg. Strain gauge) Electrical engineering (eg. Digital filtering) Physics/Dynamics (eg. Moment of inertia) Computer science (eg. Numerical methods) And Clinical neuron physiology (eg. Surface EMG) Relevantmathematicaltoolsincludelinearalgebra,differentialequations,vectorand tensor calculus, numerics and computation techniques such as finite element method. The study ofbiomaterialsisalsoofcrucialimportancetobiomechanics.Forexamplethevarioustissues withinthebodyorganssuchasskin,boneandarterieseachpossessuniquematerialproperties. Passive mechanical response of a particular tissue can be attributed to characteristics of various proteins,suchaselastin,collagen,livingcells,groundsubstancesproteoglycansandthe orientations of fibers with in the tissue. For example if human skin is largely composed of a protein other than collagen many of itsmechanicalpropertiessuchasitselasticmoduluswouldbedifferent.Alsothepropertiesof living tissue can be affected by applied loads and deformations. Ingeneral,humanmovementisbroughtaboutbythemusculoskeletalsystem (skeleton,joints,skeletalmuscles)underthecontrolofnervoussystem.Allmovementsand changes in movements are brought about by action of forces. Two most common types of forces arepushingandpullingbuttherearemanyvariationssuchas,liftingabookfromatable, holding a pen, turning a door handle, kicking a ball and throwing a discus. The muscles pull on thebonesinordertocontrolthemovementsofthejointsandindoingso,controlsthewhole body movement. Keytounderstandbiomechanicsisthoroughunderstandingofconceptsofforce, Newtons laws of motion, work and energy. Scope of Biomechanics in Medicine: Sincebiomechanicsisthescienceinvolvingthestudyofbiologicalsystemfroma mechanical perspective, it is helpful -to address problems related to human health and performance -tounderstandhowcertainphysiologicalsystemfunctions(eg.Cardiovascular system) -To model the system -To aid in the system of prosthesis Scope in Medicine field: -Molecular biology -Surgery -Cardiovascular system -Orthopedics -Trauma -Atheroscelerosis -Endothelial cells -Pulmonary organs Molecular Biology: Makes understand the formation, design, function and production of molocules. Surgery: Eventhoughthisseemstobeunrelatedtomechanics,yethealingandrehabilitationare intimately related to the stress and strain in tissues. CardioVascular system: Inventionandanalysisofprosthesisheartvalves,developmentofheartassistdevices, extracorporealcirculationdevices,heart-lungmachinesandtheheamodialysismachines.Also in heart transplantation and artificial heart replacement. Trauma: Helpssolvingproblemsofpostoperativetrauma,pulmonaryedema,pulmonary atelectasis, arterial pulse wave analysis, phonoangiography. Atheroscelerosis: Analysisofturbulentnoiseasindicationsofatheroscelerosisorstenosisinarteries.Itis studied intensely as a heamodynamics disorder because the locations ofatheroscelerotic plaques seems to correlate with certain features of blood flow. Endothelial cells: Stress acting in endothelial cells and response of endothelial cells to the stress are studied for treatment. Orthopedics: Mostfrequentusersofthesurgeryroomsarepatientswithmusculoskeletalproblems. Biomechanics is used in surgery planning, for prosthesis, implantable materials Andartificiallimbs.Alsoincellularandmolecularaspectsofhealinginrelationtostressand strain and in tissue engineering of cartilage, tendons and bones. Veryimportantly,applicationofbiomechanicsintraumaandinjury&rehabilitationis becoming more essential to society. Because people injured automobile road accidents and other incidences are younger and hence the economic impact on the society is bigger. Biomechanics in sports and exercise: Biomechanicsofsportsandexerciseisthestudyoftheforcesthatactonandwithin the human body and the effects of these forces on the size, shape, structure and movement of the body.Insportsandexercise,biomechanicsisthescienceunderlyingtechnique,everytimea coach / instructor attempts to improve an individuals technique (i.e) to improve the coordination of the forces produced by various muscle groups. [Mechanics of individual movement] Benefits of Biomechanics: Greater understanding of physiological behavior of living tissues, researchers are able to advance the field of tissue engineering as well as develop improved treatment for a wide array of pathologies. Applications of Biomechanics: -Improving physical function (Surgery planning in cerebral palsy) -Musculoskeletal Health (Replacing injurious falls by older adults preventing bone loss) -Product design (Athletic shoes, Prosthetics) -Forensic Biomechanics (Accident Investigation) Uses of Biomechanics: -Improvingsportsperformancebymeansofbettertechniqueandtrainingandalso better equipment -Sports injury byidentifying safer techniques, reducing therisk of injuryby training, and also by developing protective equipments( eg. Knee brace) -OccupationalInjuryprevention[Ergonomics]eg.Lowbackpain,hand&wrist trauma -Injury rehabilitation by identifying when safe to return to activity Who uses Biomechanics? Physicaleducationteachers,Coachers,Trainers(personal/Athletic),Physicians, Athletes, Physical Therapist, Occupational Therapist, Engineers and Researchers. Mechanics of Hard Tissue: Hard tissue, mineralized tissue and calcified tissue are the bone synonyms for describing structureandpropertiesofbone/tooth,whereassofttissuesarenothingbutmammaliantissue. Mineralized and calcified in the sense in addition to principle protein Collagen and other proteins Glycoprotein and Polysaccharides comprising about 50% of the volume, the major constituent of boneisCalciumPhospate,intheformofcrystallinecarbonateapatite,similartonaturally occurring minerals. Bones: Skeletal structures are adapted to support musculoskeletal loads. The structural properties andfailureforceofskeletalstructureiswelladaptedtofunctionalloads.Theprimary responsibilityoftheskeletonistoprovidestructuralsupportforthebody.Inthisrole,the skeletonisthebasisofposture,opposesmuscularcontractionresultinginmotion,withstands functional load bearing function and protects internal organs. Bones are rigid organs that forms part of the endoskeleton of vertebrates. Theyfunction to move, support and protect the various organsof the body, produce red and white blood cells andstoreminerals.Bonetissueisatypeofdenseconnectivetissue.Becausebonescomeina varietyofshapesandhaveacomplexinternalandexternalstructuretheyarelightweight,yet strongandhard,inadditiontofulfillingthismanyotherfunctions.Oneofthetypesoftissues thatmakesupboneinisthemineralizedOsseous tissue,alsocalledbone tissue.Thisgivesits rigidity and a honey comb like three dimensional internal structure. Other types of tissues found intheboneincludesbonemarrow,endosteumandperiosteum,nerves,bloodvesselsand cartilage. Generally, adults have 206 bones and infants have about 300 bones. The Longest bone found in humans is thigh bone called Femur.Definition and properties: Boneisananisotropic,heterogeneous,inhomogeneous,nonlinear,thermorheologically, complexviscoelasticmaterial.Itexhibitselectromechanicaleffects,presumedtobedueto streaming potentials both in vivo and in vitro when wet. It exhibits piezoelectric properties in dry state. Composition of Bone: Thecompositionofbonedependsonalargenumberoffactorssuchasspecies,which bone,locationfromwhichthesampleistaken,agesex,typeofbonetissue.Byvolume,rough estimateforoverallcompositionisonethirdofApatitecrystallites,onethirdofCollagenand other organic components and one third of water. Composition of human bones is given as1)water 25-30% 2)Minerals 60-70% (resists compression) Calcium phosphate 85% Calcium carbonate 10% Calcium fluoride 2-3% Magnesium fluoride 2-3% 3)Protein(Collagen) 5-15% (resists tension) Boneisacompositematerialcomposedof66%hydroxyapatite(HA)crystalsand33% typeICollagenfibrils(bydryweight).HAcrystalsarestrongandstiffbutbrittle,collagen prevents brittle cracking Characteristics: The primary tissue of bone , osseous tissue is a relatively hard and light weight composite material formed mostly of calcium phosphate in the chemical arrangement Termed calcium hydroxyl apatite( this is the osseous tissue that gives bones this rigidity) It has relatively high compressive strength but poor tensile strength of 104-121 Mpa, meaning it resists pushing forces well, but not pulling forces. While bone is essentially brittle, it does have a significant degree of elasticity, contributed chiefly by collagen. All bones consists of living cells, embedded in the mineralized organic matrix that makes up the osseous tissue. Functions of Bones: Bones have nine main functions. They are given as follows, *Mechanical protection: Bonescanservetoprotectinternalorgans,suchastheskullprotectingthebrainorribs protecting the heart and lungs. *Shape: Bones provide a frame to keep the body supported. *Movement: Bones,Skeletalmuscles,Tendons,LigamentsandJointsfunctiontogethertogenerate and transfer forces so that the individual body parts or the whole body can be manipulated in 3D space. *Sound Transduction: Bones are important in the mechanical aspect of hearing. *Blood Production: Themarrow,locatingwithinthemedullarycavityoflongbonesandintersticesof cancellous bone, produces blood cells in a process called haemato poiesis. *Metabolism: 1) Mineral Storage: Bonesactasreservesofmineralsimportantforthebody,mostnotablycalciumand phosphorus. 2) Growth factor Storage: Mineralizedbonematrixstoresimportantgrowthfactorssuchasinsulin.Likegrowth factors, transforming growth factor, bone morphogenic proteins and others. 3) Fat Storage: The yellow bone marrow acts as astorage reserve of fatty acids. *Acid Base Balance: BoneoffersthebloodagainstexcessivepHchangesbyabsorbingorreleasingalkaline salts. *Detoxification: Bone tissues can also store heavy metals and other foreign elements removing them from thebloodandreducingtheireffectonothertissues.Thesecanlaterbegraduallyreleasedfor excretion. Also they contain yellow bone marrow. Types of Bone: 1)Cortical bone 2)Trabecular bone Compact / Cortical Bone: Thehardouterlayerofboneiscomposedofcompactbonetissue,socalledduetoits minimal gaps and spaces. This tissue gives bones their smooth, white and solid appearance and accounts for 80% of the total bone mass of an adult skeleton. It is also referred to as dense bone. The basic first level structure of cortical bone are Osteons. It is found in the shaft of long bones. Here blood is surrounded by bone.Modulus, E ~ 18 GPa Porosity ranges from 5% to 30% Trabecullar /Cancellous Bone: Fillingtheinterioroftheorganisthetrabecularbonetissue,whichiscomposedofa network of rod and plate like elements that make the overall organ lighter and allowing room for blood vessels and marrow. It accounts for the remaining 20% of total bone mass, but has nearly ten times the surface area of compact bone. It is found in the end of long bones in vertebrae and in flat bones like the pelvis. Here bone is surrounded by blood. Modulus, E ~ 1 GPa Porosity ranges from 30% to 90% Individual Bone Structure: Boneisnotauniformlysolidmaterial,butratherhassomespacesbetweenitshard elements.Itiscomposedofacellularcomponentandanextracellularmatrix.Thecellular component is made of Osteoblasts - bone forming cells, Osteoclasts - bone destroying cells and OsteocytesbonemaintainingcellswhichareinactiveOsteoblaststrappedintheextracellular matrix. The matrix which is responsible for the mechanical strength of the bone tissue is formed byanorganicandamineralphaseofhydroxy-apatitecrystals.Aliquidcomponentisalso present. Ineachcubicmmofbone,thereareabout25,000lacunaeandonemillioncanaliculi. EachlacunaecontainsanOsteocyte(OC)surroundedinbonefluid(BF).Osteocytesare connectedviagapjunctions(GJ)inthecanaliculi.Boneisremovedatthebonesurfaceby osteoclasts(OCL),theactivityofwhichactivatesdormantosteoblastsorboneliningcells (BLC). Atthesmallestunitofstructureistropocollagenmoleculeandtheassociatedapatite crystallites(abbreviatedasAp).Theformerisapprox.1.5by280nm,madeupof3individual left-handedhelicalpolypeptide(alpha)chainscoiledintoarighthandedtriplehelix.Ap crystallitesarefoundtobecorbonate-substitutedhydroxyapatitegenerallythoughttobenon stoichiometric. Crystallites are 4 by 20 by 60 nm in size. This isMolecular level. Next level is Ultra Structural.InthiscollagenandApareintimatelyassociatedandassembledintoamicro fibrilarcomposite,severalofwhicharethenassembledintofibersfromapprox.3to5 micrometer thick.NextlevelisMicrostructural.Herefibersarerandomlyarranged(WovenBone)[or] organized into concentric lamellar groups (Osteons) [or] linear lamellar groups (Plexiform bone). This is level of structure with respect to bone tissue properties.In addition to the differences in lamellar organization at this level. There arealso 2 different types of architectural structure. The dense typeof bone found for example in the shafts of long bone is known as Compact [or] Cortical bone. Amoreporous[or]spongytypeofboneisfound,forexampleatthearticulatingendsoflong tubular bones. This is called Cancellous bone[or] Trabecular bone. It is important to note that thematerialandstructuralorganizationofCollagenApmakingupOsteonic[or]Harvesian bone and Plexiform bone are the same as the material comprising Cancellous bone. Finally,thewholeboneitselfisconstructedofOsteonsandpartiallydestroyedOsteons (calledinterstitiallamellae)incaseofhumans[or]ofosteonsandorplexiformboneincaseof mammals. This is macrostructural level.Structure of human Femur bone: A Femur with a cortex of compact bone and medulla of trabecular bone.It consists of a shaft(diaphysis)withanexpansion(metaphysis)ateachend.Themetaphysicissurroundedby an epiphysis which is united by a cartilageous growth plate. At the extremity of each epiphysis a specializedcovering of articular cartilage for the gliding surface of the joints. The coefficient of dry friction between the articular cartilages of the joints is very low and the coefficient of friction is0.0026.Hencethecartilagecoveringmakesanefficientjoint.Thegrowthplateisaplace where calcification of the cartilage takes place.Thediaphysisisahollowtube,itswallarecomposedofdensecortexwhichisthick throughouttheextentofdiaphysis.But,tappersofftobecomethinshellofmetaphysis.The central space within the diaphysis contains bone marrow, covering the entire external surface of a mature long bone, except for the articulation is periosteum. The inner layer of the periosteum contains highly active cells that produce circumferential enlargement.It is called asOsteogenic layer.Aftermaturity,thislayerconsistschieflyofcapillarybloodvesselnetwork.Theouter layer of the periosteum contains collagen and is loosely attached. The basic unit is the Haversian system[or] Osteon. In the center of an osteon is a artery orveinwhichsupplyblood.Thesebloodvesselsareconnectedbytransversechannelscalled Volkmanns channel. About two third of the weight of the bone is the inorganic material and the materials are hydroxyl-apatite, calcium phosphate and small quantity of ion. The rest of the bone is organic material mainly collagen. The hydroxyl-apatite crystals are arranged along the length of collagen crystals. Groups of collagen fibers run parallel to each other to form fibers. Elastic properties: The elastic properties of the whole bone results from the hierarchical contribution of each of these levels. ThedensetypeofbonefondforExampleintheshaftsandlongboneisknownas compact (or) cortical bone. A more porous (or) spongy type of bone is found, for example at the articulating of long bones this is called cancellers bone (or) trabulular bone example ribs. It is important to hate that the material & structural organization of calljen Ap making up oceanic (or) harersian bone and plexi form bone are the same as the material comprising cancellas bone. Finally, we have the whole bone itself Constructed of and partiallydestroyed called in (lamellae) in caseof humans or ofosteans and or plexi form bone in the case of mammals. This is macro structural level. The elastic properties of the whole bone results from the hieraschical contribution of each of these levels. Composition of Bone: The composition of bone depends on a large no of factors. Species, which bone,location from which the sample is taken, age,sex,type of bone tissue for example : worsen,cancellaes/cartocal.By volume rough estimate foroverall composition is 1/3 rd AP, 1/3rdand other organic components, 31 rd it20. Elastic Properties:Determination of in vivo elastic modules. Althoughboneisaviscoelasticmaterial,atthequasi-staticstrainratesinmechanical listingandevenattheultrasonicfrequencyusedexptly,itisreasonablefirstappesttomodel corticalboneasananisotroper,linearelasticsolidwithhookeslowastheappropriate constitutive example. Tensor rotation for the equation is written as, kl cijkl ij e = o----------------------- (1) kl ij e , o Second rank stress& infinites final second rank strain centers. Cijikl Forth rank elasticity lenor. Usingreduced rotation, re writing equation (1) as, cijtj i = oc, j =1 to 6--------------------------- (2) Ij stifners coefficient (elastic constants) The inverse of (ij, the sij are known as complain coefficient. Theanisotropyofcorticalbonetissueisdescribedin2symmetryarrangements.Itis assumed bone to be transferablyisotropic with the bone axis of symmetry as the unique axis of symmetry. (long yoon,Katz) Any small difference in elastic Properties below the radial of ( ) axes,due to the apparent gradient in porosify from the perios teal to the endosteal sides of bone, was dueto the defect did not alter the basic symmetry. For a transverse isotropic material, the stiffhers matrix (cij) is given by, ( )(((((((((

=66 0000440 00000 0000000000004433 13 1313 11 1213 12 11CCC C C CC C CC C Ccij Where, C66=1/2 (C11 C12) -------------------- (3) Cutof12nonzerocoefficientonly5areindependent(vanbuskirk,Ashman)theyusedsmall differences in elastic properties below the radial & tangential directions to postulate that bone is an orthotropic material, this requires that 9/12 non zero elastic constants be independent, That is, (((((((((

=66554433 23 1323 22 1212 11000000 000000 0000000003000) (CCCC C CC C CC C CCij---------------------------------- (4) Corresponding matrices can be written for the compliance coefficient the Sij based on the inverse equation to equation (2). j Sij i o c =i,j=1to 6---------------------------------------- (5) Where the Sij th compliance is obtained by dividing the (Cij )stiffness matrix, minus the 11th row & jth column, by the full(Cij) matrix and vice versa to obtain the Cij in terms of the Sij . ThusAlthoughS33=1/E3.WhereE3isyoungesmodulusintheboneaxisdirection, ,33 3C = cSince C33 and S33 are not reciprocals of one another even for an isotropic material. Let alone for transfers isotropy (or) ortho topic symmetry. Therelationshipbetweenthecompliancematrixthetechnicalcanstants suchasyoungs modulus(Ei),Shearmodulus(Cri)poisonsratio(Vij)measuredinmechanicaltestssuchas uniaxial (or) pure shear given in equation (6) [ Sij]=(((((((((((((((

010000010000001000100011311233 2231133322 1123312211CCE EVEVEVE EVEVEVE ------------------------------------- (6) Againforanorthotropicmaterial,only9/12nonzerotermsareindependentduetothe symmetry of the Sij332223331113221112EVEVEVEVEVEV= = = ---------------------------------- (7) For transverse isotopic case, Equation (5) reduces to only (5) independent coefficient. Since, 23 13 32 31 21 12 2 1V V V V V V E E = = = = =31 23G G= ) 1 ( 212112VEG+=------------------------------------- (8) Inadditiontomechanicaltests,ultrasonicwavePropagationtechniqueshavebeenused tomeasuretheelasticpropertiesofbone.ThisispossiblesincecombiningHookeslawwith Newtons 2nd law results in a wave equation that gives fall relation involving the stiffeners matrix. PV2 Um= Cmrns Nr Ns Un P density of medium Vwave speed U,NUnitvectorsareasparticledisplacementwavepropagationdirection.(Direction cesires) Major advertising of ultrasonic measurements over mechanical testing is formers can be done with specimens to small for the latter technique. Second, the reproducibility of measurements using former is greater than latter. Third, adjective full let of either five or 9 coefficient can be measured an one specimen a procedure not possible with letters. Haversian Bone: Alsocalledosteonic.Theformofbonefoundinadulthumansandmaturemammals consistingmainlyofconcentriccamellarstructuressurroundingacentsalcanalcalledhaverson canal. Also the central portion of the blood stays in the center of the vessel. This type of flow is laminar flare or stream line flow. Parabolic Velocity profile during laminar flow. Whenlaminarflowoccurs,thevelocityofflowinthecenterofthevesselisforgreater than towards outer edge. The portion of the fluid adjacent to the wall has hardly moved. The portion slightly away from the wall has moved a smaller distance and the portion in the center has moved a longer distance. This effect is called as the parabolic profile of the velocity of blood flow. Thecausefortheeparabolicprofileisthefluidmoleculestouchingtherewashardly move because of adherence to the vessel wall. Thefluidinthemiddleofthevesselcanmoverapidlybecauseoftheexistenceof sliping molecules in the middle of the vessel. Turbulent Flow of Blood:- Whentherateofbloodflowbecomestoogreat(or)whenitpassesanobstructionina vessel (or) when it make a shape turn (or) when itpasses a rough surface, the flow may become turbulent. The blood flows cross wise in the vessel as well as along the vessel. Usually forming whorles in the blood called eddy current. Whentheeddycurrentarefarmed,thebloodflowwithmuchgreaterresistancethan when the flow is streamlined, because the eddy act tremendously to the overall friction of the flow in the vessel. ( )( )ityofblood Visl bloodvesse diameterof Velocitylow TurbulentfcosThedensetypeofbonefondforExampleintheshaftsandlongboneisknownas compact (or) cortical bone. A more porous (or) spongy type of bone is found, for example at the articulating of long bones this is called cancellers bone (or) trabulular bone example ribs. It is important to hate that the material & structural organization of calljen Ap making up oceanic (or) harersian bone and plexi form bone are the same as the material comprising cancellas bone. BIO FLUID MECHANICS Fluids: Fluidisasubstancewhichdeformscontinuouslywhensubjectedtoshearforces.The tendencyofcontinuousdeformationofasubstanceiscalledasfluidityandtheactof continuous deformation of a body is called as flow. Asolidhasatendencytoregaintoitsinitialstate.Ontheotherhand,afluiddeformed continuously (or) flowswhenshear ferce is is applied, then fluid suffers rate of shear strain (or) strain rate. Shear stress proportional to rate of shear strain. dyduJXmJ-Shear stress (stress which is applied parallel (or) tangential to aface of a material) M-Viscosity of fluidU-Velocity (or) Velocity gradient The equation that describes the relationship between stress & strain (or) rate is called as constitutive equation. c o E =dyduJXmThis equation is known as Newtons law of viscosity. Newtonian Fluid:- The fluid which obeys this law is called as Newtonian fluid. In this equation, M is the slope of the Hookes law of elasticity for solids. Example:- Water, Molten metals. Hookes LawNewtons Law Stress strain shear stress shear strain Young s modules modulus of elasticity Shear stress rate of shear strain Viscosity dyduJXViscosity:- It is an internal property ofa fluid material which offers resistance to flow. Viscosity is denoted by the symbol n and is measured in units of pas Vga9) ( 22A= V Velocity a radius g acceleration due to gravity p difference in density between sphere and liquid. Properties of Viscosity:- -Varies with temperature -Independent of pressurebut liquid under extreme pressure of the experience an increase in viscosity. Types of viscosity:- 1.Absolute / dynamic viscosity 2.Kinematic Viscosity Effects of viscosity:- Theeffectofviscosityinafluidflowwillgiverisetoshearstresswhichopposethe motion of the neighbouring element in a flow. The velocity gradient depends up on boundaryCondition.Thevelocityofafluidincontactwithboundarymustbesameasthatofthe boundary. Forexample , the viscosity of a fluid flowing through the stationary pipe should be zero at the wall. This is the condition of No Slip or No Slip Condition Non Newtonian fluid:- Viscosity is not constant. Any fluid that does not obey the Newtons law of Viscosity is calledasNonNewtonianfluid.Here,theslopeofshearstressVsstrainratewillnotbea constant. Example is liquids in which fine paLiquids in which fine particles are suspended, slurries and paste. Classification of fluids:- 1.Visco elastic fluids -Shear thinning fluids (Pseudo Plastic fluids) -Shear thickening fluids 2.Visco plastic fluids 3.Thexotrophicfluids 4.Pheopectic fluids Visco Elastic Fluids:- Itcomprises of 2components i.e. viscosityand elasticity. A typicalexample forsucha typeisbloodviscosityisrelatedtotheenergydissipateduringflowduetoslidingand deformationofRBCandredbloodaggregate,whereastheelasticityisrelatedtotheenergy stared during flow due to orientation and deformation of RBC. Shear Thinning Fluids (Pseudo Plastic Fluids) Whenviscositydecreaseswithincreaseinshearrate,thefluidissaidtobeshear thinning fluids also called as pseudo plastic fluidsExample: - Latex paintManyshearthinningfluidswillexhibitaNewtanianbehavioratextremelyhighshear rate. Shear Thickening Fluids: Whenviscosityincreaceswithincreaseinshearrate,thefluidiscalledasShear thickening fluidsExample:- Clay slurries. Shear Thinning fluidViscoplastic Fluids:- This is a fluid which will not flow when a small stress is applied. The shear stress must exceed a critical value to for a fluid flow. Example:- Tooth paste It behaves like solids, when the applied shear stress is less than yield stress. Thexotrophic Fluids:- Itisthepropertyofsomenon-newtanianfluidstoshowtimedependentchangein viscosity. Example:- Gells and colloidsRheopectic FluidsThe langerr the fluid undergoes shearing force, the higher is its viscosity. Example:- Gypsum paste and printer inks thickens (or) Solidifies when shaken. Bio Fluid Mechanics: Itisthestudyofcertaincleanofbiologicalproblemsfromafluidmechanicspointof view. It does not involve any new development of the general principles of fluid mechanics but it does involve some new applications of the method of fluid mechanics. Theflowbehaviorofbiologicalfluidsinlivingorganismsplaysacrucialrolein determining the state of the tissue through which they flow. Bio fluid mechanics study of fundamental of biological fluid flow is extremely important fortheunderstandingofhowchangesinhowbehaviorswhichlivingtissuemaybeaffectboth the fluid and the tissue. Fluids in living tissues include blood, waters air and body fluids of animals as well as the fluids in plants. Themeasurementandbalanceofforcesinrestingfluidsandfluidsinmotionareaway the basic subjects forresearch.Bio fluid mechanics field where importance to the field of bio engineeringhas increased over the last two decadespharmaceuticals bio materials and non invasive diagnostic and surgical procedurescreateinthefluidmechanicsofbiofluids.BiofluidMechanicsisacomplexfield including important areas of study blood flow & cardio vascular diseases. Complex hemodynamics play a critical role in the development of other osclerise process of using also other diseases. It is important to understand the forces and movement of blood cells and whole blood as under tandins the blood in the cardiovascular circulators sustain of the human body. V scarity and flow behaviors changes medicatron can influence flow behaviors . Heamoclo strange influence on creation of ancymes & varicose veins. Verbal wall structure (geometry, elasticity) determines flow behaviors. Fluid Dynamics Factors: Flowrateratio,pressure&velocitygradients,&flowbehaviors,velocitydistribution, shear stress pm the wall and on blood cells. These mechanical factors are longly responsible for the deposit of blood cells and lipds a leadingcourseofartho.Thesedependsandfoundpredetermaindsatarterialblends&where blood flow is distributed where a secondary flow is created (or) where flowHumanbodyisacomplexsustainthatrequiresmaterialssuchasair,water,mineralsand nutrients for survival and function. Upon in these materials have to be trans ported & distributed around the body as regarding. Thebiotransportanddistributionproceduresinvolveinteractionswithmembranescells tissues and organs comprising the body. Subsequenttocellularmetabolisminthetissues,wastebyproductshavetobe transported to the extency organs for synthesis & remade. In addition to these functions, bio transport systems and proceder. Are regarding for homeostasis and for (homeostasisphysiologicalregulationexamplemaintenanceof PH&body temperature) Enablingthemovementofimmunesubstancestoaidinbodysdefenseandrecovery from infection & injury. In of ear,fluid transport enables hearing and motion sensing. -In human body multiple types of fluid dynamic systems that operate at multiple &widelydisparatescalesatvariouslevelssuchasmicro,macro,nano,pice& soon.Ex.cell,tissue (macro,organs (Macro) -Transportatmicro,nano&piceinclude,Channeling,binding,Signaling, endocyosis & soon. -Tissue constitute organs, organs as systems perform various functions. Ex. Cardio vascular system consist of the heart blood vesels (astesies,artei,Veins & capillaries ) lymphatic vesels and the lungs. Its function is to provide adequate blood flow & resultant the flow as required by the various organs of the blood. Flow Properties of Blood: Blood :An out line Bloodisamarvelsfluidthatneutrinoslife,containsmanyenzymesandhormons& transport oxygen, & Co2 between lungs & cells of the tissues. Humanbloodisasuspensionofcellsinanaqueonssolutionofelectrolytesandnon electrolytes. By centilusation, the blood is separated into plasma and cells. Plasmaisabout90%waterbyweight,7%Plasmaprotein,1%inorganicsubstrains,and 1% other organic substances. Cellularcontentsareessentiallyallerthyocytes(or)RBCwithWBCofvariance categorieswhichmakes