donderdag 29 mei 2014

Materiaalkune 1 on OCW Delft lesson 2

Materiaalkunde 1 on OCW Delft lesson 2 

In this lesson I learned more on the properties of materials. One specific property that stood out for me was Dielectric strength. Other topics were the classification of materials in families and counting with logarithms. 

Material properties 

As mentioned dielectric strength stood out for me as it is a property to which I don't have an intuitive grasp. The guy in the lecture defined it as follows: 
"The dielectric strength of a material is a measure of how much a material will interact with electromagnetic waves"
And he had this picture on. But what does it mean?! So the radar sphere has a low dielectric response and the ships beam has a high response thereby making it visible on the radar? I think so, so basically high dielectric response indicates that a material will interact with electro magenetic waves, like the definition said... right
uh.. what?
To grasp this subject I first tried Khan academy which has a really good lesson on this. Other websites that were helpfull to me were:
 and this websites has some interesting information on dielectricity:

σ/(ωε’)Current conductionField propagation
0perfect dielectric
lossless medium
≪ 1low-conductivity material
poor conductor
low-loss medium
good dielectric
≈ 1lossy conducting materiallossy propagation medium
≫ 1high-conductivity material
good conductor
high-loss medium
poor dielectric
perfect conductor

This is already very helpfull in my day to day work. Getting a more intuitive grasp of dielectrics also gave me a better grasp of capacitance. A dieelectric is an intergral part of a capacitor. As a dielectric material increases the capacitance rating of a conductor. 

Classification of materials 

A helpfull and quite intuitive section of this lesson was the classification of materials. Basically it helps me group materials by family. For this classification to be really helpfull it would be good to know what the basic properties of each material family is.

dinsdag 6 mei 2014

Material science 101

Being my inquisitive self, I have decided I would like to learn how the Finite Element analysis actually works. However having studied biomedical engineering this was not an obvious subject and I do not have the necessary background information to grasp it. So what do you do? 

I just finished the first lecture and what stuck was the following. I liked the part of putting energy usage in perspective. That we as dutch citizens have on average about 6 kW/s working for us compared to ~2 kW/s for the average world dweller is quite a difference.
Everyday energy costs, note the amount of energy it takes to power a house/car 
Moving on to the actual material science part of the lecture. I learned the basic properties of materials. Which you know by experience but I need to find how to get an intuitive grasp of these concepts. Take Elastic modulus for example... what does that mean, which materials have a high/ low Emod? high would be steel and low would be plastics... meaning... meaning... meaning... meaning that steel is harder to bend than plastics, right? correct me if I am wrong. 

The picture below helps kind off to make sense of these properties: 

All in all an interesting lecture and I am determined to follow at least 3 more lectures. The key to happiness is to set low expectations  :P