Download Modelling

http://funfive.net/pictures/how-it-s-in-the-hospital/12384.html
Αρχαια Αρχιτεκτονικη και Υλικά
Bio-System
Engineering
Genetic
Engineering
BioFluid Mechanics
& BioHeat Transfer
BioEngineering
Tissue
Engineering
Medical
Physics
Biomechanics
Τι γνωριζετe απο μοχλους (levers);
Force 1
Force 2
The bull - 1945
Watch the Process:
https://www.youtube.com/watch?v=Kg4G3x2HSEI
BioMechanics
Statics
Dynamics
Tools/Skills you need:
• Anatomy (Da Vinci, Borelli…)
• Mass/Center of Mass, Forces, Moments
• Free body Diagram (διάγραμμα ελευθέρου
σώματος)
• Newton’s Laws
Λίγο από Στατική...
Διαγραμμα Ελευθερου Σωματος
&
Στηρίξεις
Στατικη: εξετάζει τις συνθήκες κάτω από τις οποίες
ένας σωμα (φορέας) στέκεται, δηλαδή ισορροπεί
Τι ειναι ο ‘Φορεας’;
Φορεας ειναι ενα στερεο σωμα που δεν
μπορει να παραμορφωθει.
Σαν συνεπεια ο φορεας μπορει να μεταφερει
ολα τα φορτια στα οποια ασκουνται πανω του.
Free body Diagram (FBD)
From Wiki:
A free body diagram is a sketch, used by engineers and
physicists, to analyze the forces and moments acting on a body.
Question: why it is called the ‘free’ body?
https://voer.edu.vn/c/normal-tension-and-other-examples-of-forces/0e60bfc6/ca96f97a#import-auto-id2149297
Τι είναι Στήριξη;
Στηριξη: μια διαταξη που στηριζει ενα φορεα,
δηλαδη μπορει να ‘παραλαβει’ καποιο φορτιο
(δυναμεις, ροπες) απο το φορεα.
Στήριξη ΙIΙ : Πάκτωση
Εχουμε ΠΑΚΤΩΣΕΙΣ μεσα στον ανθρώπινο οργανισμό;
Στήριξη ΙΙ : Αρθρωση
Εχουμε ‘αρθρωσεις’ μεσα στον ανθρώπινο οργανισμό;
Παραδειγμα Αρθρωσης: Τραμπάλα
Στήριξη Ι : Κύλιση
Εχουμε ΚΥΛΙΣΕΙΣ μεσα στον ανθρώπινο οργανισμό;
Τεστ.
Στηρίξεις στην καθημερινή ζωή;
2. Αρθρωση
Roller Skating, 1905
Hinge
1. Κύλιση
3. Πάκτωση
Test Problem 1.
Object of Weight W1
Ραβδος βαρους W2
Αρθρωση Ο
Force F
1. Draw the Free Body Diagram (?)
2. Calculate the unknown force F
3. Calculate the Reaction Forces at the Joint ‘O’.
Test Problem 2.
Object of Weight W1
Ραβδος βαρους W2
Πακτωση
(fixed end of the
beam)
Force F
1. Draw the Free Body Diagram (?)
2. Calculate the Reaction Forces & Moment at the fixed
end of the beam (is F needed?)
Test Problem 3.
Object of Weight W1
Ραβδος βαρους W2
Πακτωση 2
Πακτωση 1
1. Draw the Free Body Diagram (?)
2. Calculate the Reaction Forces moment at the fixed ends
BioMechanics
MECHANICS: study of physical action of forces
(and moments)
Mechanics is divided into:
(Α) Statics: Study of systems
that are in a constant state of
motion (with zero or constant
velocity)
(Β) Dynamics: study of
systems in motion with
acceleration
Static BioMechanics
Calculate Forces and Moments in Muscles, Joints and Bones
Applications:
Sports, Rehabilitation (exercise in elderly arthritis patients,
muscle strengthening in rheumatoid arthritis)…
Static BioMechanics
Calculate Forces and Moments in Muscles, Joints and Bones
http://news.bbc.co.uk/2/hi/6187080.stm
More Applications: Ergonomics, Arthroplasty…
The Process of Solving a Problem
1. What is the Problem?
2. Get to know the Anatomy
Connect the Anatomy to the Problem…
3. Modelling: A Reduction Process
A Physical Model
Force F
REALITY
MODELLING
Assumptions
Modelling and Picasso?
Watch the Process:
https://www.youtube.com/watch?v=Kg4G3x2HSEI
Modelling Humans
1) Bones: as Rigid Bodies
(φορεις)
2) Muscles: as Forces
(need to know the
location of the muscle
attachment)
3) Human Joints: Σαν
Αρθρωσεις
What about Ligaments & Tendons?
Modelling Bones
Bone
Φορεας
Force due
to Weight
Bone Weight
Is the above a FBD?
Modelling Human Joints
Human joints are modelled as ΑΡΘΡΩΣΕΙΣ...
http://www2.estrellamountain.edu/faculty/farabee/BIOBK/BioBookMUSSKEL.html
Q: What type of Joint is
the Elbow Joint?
http://www.physioroom.com/injuries/arm_and_elbow/elbow_arthritis_full.php
4. Free Body Diagram
(for EACH element of the model)
Free Body Diagram
Weight of Object
Force F
Reaction Forces
5. Mathematical Description
(based on physical laws):
Newton’s 1st Law.
Ενας φορεας σε ισορροπια:
𝑛
� 𝐹𝑖 = 0
𝑖=1
𝑚
� 𝑀𝑖 = 0
𝑖=1
Do not forget:
Moment With Respect to a Point!
An Example
Lifting weight with your biceps
How Much Force your Muscles generate?
(Why lifting weight?)
Created in 1933
Rehab
The Luncheon on the Grass, 1863
Edouard Manet
1. What is the
Problem?
How Much Force
your Muscles
generate?
It is a Complicated
Problem!
http://www.sportsposterwarehouse.com/detail_FINFC09__458__bicepsforearm05fi_htm.html
2. Anatomy of a Forearm
What Muscles are Important?
http://www.maloneyperformance.com/Blog/?p=390
Three Major Muscles involved
BIC: Biceps
BRR: Brachioradialis
BRA: Brachialis
http://en.wikipedia.org/wiki/Anatomical_terminology
Modelling: Version I
BIC: Biceps
BRR: Brachioradialis
BRA: Brachialis
http://www.engrevo.com/blog/biomechanics-of-bicep-curls/
Free Body Diagram of the Model
Muscle
Forces
Reaction
Forces
Rigid Body
Weight
Can the problem be (mathematically)
solved?
How many Equations,
how many Unknowns?
Anatomy of a Forearm (again)
Neglect BRR & BRA…
http://www.angelfire.com/la/Ivan/PT.html
http://www.ib.bioninja.com.au/higher-level/topic-11human-health-and/112-muscles-and-movement.html
Modelling: Version II
REALITY
MODELLING
Assumptions
http://www.bcit.ca/bettermath/example1submitted.shtml
4. Free Body Diagram
(for EACH element of the model)
Is this a correct FBD?
Muscle
Forces
1. UPPER ARM
Weight
2. LOWER
ARM
Muscle
Forces
Reaction
Forces
Weight
Rigid Body
Weight
Reaction
Forces
Can the problem be (mathematically)
solved?
Equations:
Unknowns:
Example 2: Push Ups
Question 1: What force should the woman exert on
the floor with each hand to do a push-up? (Ans: 147 N)
http://cnx.org/contents/d703853c-6382-4035-8d6a-dcbca00a15ca@5/Forces_and_Torques_in_Muscles_
Example 2: Push Ups
Question 2: Calculate the magnitude of the force in
each triceps muscle, and compare it to her weight.
http://cnx.org/contents/d703853c-6382-4035-8d6a-dcbca00a15ca@5/Forces_and_Torques_in_Muscles_
Quiz: What is that?
The number of Unknown Variables of muscle forces and joint forces
and moments Exceeds the number of Available Equations. This is
primarily because of the redundant nature of anatomic structures.
There are multiple muscles that can execute synergistic functions.
Mathematically, this problem has NO unique solution.
Text taken from: ‘Estimation of Muscle and Joint Forces during Push-up’
http://avmedia.info/blog/how-to-do-perfect-push-ups-for-beginners/
When Multiple Muscles are involved, then the
problem CANNOT (probably) be solved….
We:
- Need to make further Assumptions (reduction process)
Or
-add more Equations (physical laws) that connect the
unknowns…
Or
-Run Experiments
Making Assumptions…
Assumptions:
-Only the Triceps muscle are involved.
-The triceps muscle at the back of her upper arm has an
effective lever arm of 1.75 cm, and she exerts force on the
floor at a horizontal distance of 20.0 cm from the elbow joint.
Ans: 1680 N, 3.4 times her weight
http://mybodyisblank.tumblr.com/post/4406344604/diamond-pushups
When Multiple Muscles are involved, then the
problem CANNOT (probably) be solved….
We:
- Need to make further Assumptions (reduction process)
Or
-add more Equations (physical laws) that connect the
unknowns…
Or
-Run Experiments
Run Experiments?
ElectroMyoGraphy (EMG)
…A technique for recording the ELECTRICAL
activity produced by muscles.
Skin (surface) Electrodes
To diagnose Neuromuscular Diseases & study Kinesiology
Two types of Electrodes
Needle
Electrodes
Skin (surface)
Electrodes
Skin electrodes measure the differential voltage from two
electrodes on the skin and amplify the signal.
Pros and Cons between the 2 types of electrodes?
How does it work?
Needle electrodes detect Ions in muscle contractions & their strength
http://www.medicalexhibits.com/medical_exhibits.php?exhibit=07030_03X&query=treatment%20nerve..
EMG & The Nerve Conduction Test
EMG & Push-ups
EMG Experimental Data
More info :‘ANALYSIS OF PUSHING EXERCISES: MUSCLE
ACTIVITY AND SPINE LOAD WHILE CONTRASTING
TECHNIQUES ON STABLE SURFACES WITH A LABILE
SUSPENSION STRAP TRAINING SYSTEM’
Remember the Brain-Computer
Interface?
- Electroencephalography
(EEG) uses Surface Electrodes
to record electrical activity
along the scalp.
- To diagnose epilepsy, sleep
disorders, coma, encephalopathies
Hans Berger, 1924
http://en.wikipedia.org/wiki/Electroencephalography
Resting Potential in Neurons
http://higheredbcs.wiley.com/legacy/college/tortora/0470565101/hearthis_ill/pap13e_ch1
2_illustr_audio_mp3_am/simulations/hear/membrane_potential.html
Action Potential in Neurons
http://biology4isc.weebly.com/7-nervous-system.html
Remember the Brain-Computer
Interface?
Time
http://en.wikipedia.org/wiki/Electroencephalography
Bone Calcium and Weight Lifting?
Exercise plays an important role in maintaining bone calcium and
strength as people age. Studies show that exercises requiring
muscles to pull on bones (resistance exercise) cause the bones to
retain and possibly gain calcium (density).
Q: What is the big deal?
http://www.nytimes.com/health/guides/specialtopic/physical-activity/exercise%27s-effects-on-bones-and-muscles.html
EXAMPLE 3: Spinal Load
Spinal Mechanics
Why studying it?
Back Pain…
• 90% of adults experience back pain at some point in
their lifetimes.
• Most common cause of job-related disability and a
leading contributor to missed work days.
http://www.mposition.pl/en/Accept-mPosition/Ergonomics
Architecture of a Spine
Lower Back
Οσφυϊκό
Κυρτωμα
Q: Can you identify:
Kyphosis, Lordosis, Scoliosis?
http://trikonansan.blogspot.gr/2010/07/your-lumbar-curve-keeping-it-healthy.html
Anatomy: A Closer View
The SPINAL CORD is the
pliable main nerve
that runs from your
brain through your spine
MUSCLES help to hold up
your spine and permit
movement by contraction
Vertebrae = σπονδυλοι
The Facet Joints
The Facet Joints
can suffer from
OsteoArthritis
http://www.mycdi.com/knowledge_center/pain_management/facet_joint_injection/
The Disc
(μεσοσπονδύλιος δίσκος)
THE DISC: a pillow between two bones. It softly resists the
downward forces placed on the vertebrae from the weight
and movement of the head. A good pillow is THICK & SOFT.
Herniated = Κήλη
Spine Disc Problems
Damage in the Lower
Back (L1-L5 vertebrae)
causes LOW BACK PAIN
LOW BACK PAIN causes
40% of missed days of
work (in the US)
Spinal Decompression
Spinal decompression can be achieved
both surgically and non-surgically
http://www.mayfieldclinic.com/PE-BackPain.htm#.VOtLjC6znqo
http://drkenandersen.com/how-spinal-decompression-can-help/
Spinal Decompression
Q: How does it work?
From Wiki:
Spinal Decompression is the relief of pressure on one or many
pinched nerves of the spinal column.
http://www.espritwellness.com/blog/spinal-decompression-faqs/
Arthritis in the Spine:
Facet Joint Injection
THE PROCEDURE
A steroid medication and
an anesthetic are
injected into the capsule
surrounding the small
facet joints...
The RESUTLS
The injections do not
cure the arthritis, but
they give pain relief for
up to 3 months…
http://www.drpatriciagrant.com/FacetJointInjection.html
Q: How can you visualize the
location of injection?
Example of Spine Mechanics
How to Model the Spinal Joints?
1. Facet joints are hinge–like joints
2. intervertebral discs act as ligaments to hold the vertebrae
together
https://ittcs.wordpress.com/2010/06/10/anatomy-and-physiology-spinal-stenosis/
Lifting a Box
1) Calculate the force FB in
the back muscles that is
needed to support the upper
body plus the box. The mass
of the upper body is 55 kg
and the mass of the box is 30
kg.
2) Calculate the force Fv–
exerted by the vertebrae on
the spine at the indicated
pivot point
http://cnx.org/contents/d703853c-6382-4035-8d6a-dcbca00a15ca@5/Forces_and_Torques_in_Muscles_#fs-id1169738061293
Spinal Muscles Role In Lifting
• Spinal Muscles Have
Small Moment Arms With
Respect To the Vertebral
Joints.
• Need To Generate Large
Forces To Counteract the
Torque Produced About
the Spine by Body Weight
and Objects Being Lifted.
Erector Spinae
Muscles
A Simple Model of the Spine
Assumptions:
-The spine is a Rigid Body
-Rotation around the L5/Sacrum Joint
Class One Lever
Load
L5
http://imgarcade.com/1/first-class-lever-examples-in-the-body/
Force
Again: Lifting a Box
Can you draw the
FBD?
http://cnx.org/contents/d703853c-6382-4035-8d6a-dcbca00a15ca@5/Forces_and_Torques_in_Muscles_#fs-id1169738061293
Why Lift With The Legs?
Back Muscles (Moment Arm ~ 6 cm),
Must Counter The Torque Produced
by the Weights of the Body Plus Any
External Loads.
A More Sophisticated Spine Model
COR: the vertebral Centers Of Rotation
Reference: ‘Effect of the Intra-Abdominal Pressure and the Center of Segmental Body Mass
on the Lumbar Spine Mechanics – A Computational Parametric Study’
What Does The Research Show?
Compression Increases More with Spinal
Flexion, and Increases Still Further with a
Slouched Sitting Position.
Position and Spine Load
https://ittcs.wordpress.com/author/brucemcfarlane/page/3/
What about few extra kilos?
..Few Extra Kilos move the
Center of Mass away from the
pivot point
Can you draw the FBD?
https://chiro-trust.org/back-pain/the-key-to-preventing-spinal-pain-understanding-levers/
In Summary
-Statics: Important in understanding everyday
loads in our muscles and bones.
-Bones, Muscles and Joints can be modelled by
simple mechanical lever systems (muscles are
attached close to joints)
-Good posture: the center of gravity lies directly
above the pivot point in their hips, thereby
avoiding back strain and damage to disks.
Summary taken from:
http://cnx.org/contents/d703853c-6382-4035-8d6a-dcbca00a15ca@5/Forces_and_Torques_in_Muscles_#fs-id1169738061293