Everything

Question 0

Different force measurements methods

Answer 0

Capacitors
Piezoelectric sensors
Strain gauge sensors

Question 1

Why measure force

Answer 1

1. Provide movement patterns for use in qualitative analysis
2. highlight potential risk factors
3. Evaluate foot strike patterns
4. provide input data for modelling internal loads

Question 2

How do piezoelectric sensors work

Answer 2

Crystal generate charge in response to mechanical strain

Question 3

How do strain gauge sensors work

Answer 3

Deformation changes conductivity

Question 4

What is the process of force platforms

Answer 4

Input
Transducers
Signal conditioning 
A-d converter
Recording device

Question 5

Force components

Answer 5

Fx
Fy
Fz

Question 6

3 moment components

Answer 6

Mx
My
Mz

Question 7

How to calculate Ay

Answer 7

Mx=fz x y

Y = mx divided by fz

Question 8

How to calculate ax

Answer 8

X = -my divided by fz

Question 9

Sensor characteristics

Answer 9

Linerarity
Hysteresis
Range
Sensitivity
Cross talk
Dynamic response 
Natural frequency

Question 10

What is hysteresis

Answer 10

Input-output relationship influenced by whether input is increasing or decreasing

Low required

Question 11

Types of calibration

Answer 11

Static
Cop
Dynamic

Question 12

Calculation if impulse

Answer 12

Impulse = force x time

Question 13

Impulse momentum relationship

Answer 13

F = mvf - mvi / t

Question 14

Use of pressure data

Answer 14

Foot type
Running style
Localised pressure

Question 15

Pressure data for foot type

Answer 15

Arch contact

Pronation / supination

Question 16

Pressure data for running style

Answer 16

Foot strike

Rear foot eversion

Question 17

Pressure data for localised pressure

Answer 17

Identify high loads - cushioning

Question 18

What is modelling

Answer 18

An attempt to represent reality
Relationship between cause and effect
Abstract form

Question 19

Information required for modelling

Answer 19

Knowledge of system

Experimental data

Question 20

Why simplification

Answer 20

In general simple is better

Question 21

Purpose of models

Answer 21

To increase knowledge and insight

To estimate or predict

Question 22

Types of models

Answer 22

Direct

Inverse

Question 23

Validation / evaluation of models

Answer 23

Direct
Indirect
Trend

Question 24

What is force system analysis

Answer 24

Description of the mechanical behaviour of a system

Question 25

Components of force system analysis

Answer 25

``` System of interest Assumptions Free body diagram Equations of motion Mathematical solution ```

Question 26

Components of system of interest

Answer 26

Sketch the actual situation Divide the body at the location where the force is to be determined Systems of interest is one of the separated parts

Question 27

Assumptions

Answer 27

2d or 3d problem Which forces included / excluded Known forces Material / structural characteristics

Question 28

Free body diagram

Answer 28

Sketch system of interest A representation of all external and internal forces A reference frame

Question 29

Assumptions for ankle

Answer 29

``` The foot is a rigid structure The foot has one idealised hinge joint There is no friction at the ankle The problem can be solved 2-d All forces act through the triceps surae complex which is mediated through the Achilles tendon ```