Mechanics is an ancient subject. However nowadays, with the aid of computers,
the capability of mechanics is maximized to meet the needs of our modern technology.
Think about problems like:
How does a car resist vibration when driving on rough roads ?
How to optimize the design of a professional drone?
What s the performance of a cellphone in a drop test?
How to accurately release spine stress during an operation?
All these problems are highly related to Mechanics!
In general, Mechanics is a study of how things work, or even how the world works.
It is applied in many different technology
fields which effect the modern industry and our everyday life.
To name a few, automobile, electronics, oil industry,
biology, packaging or even sports helmets and shoes you are familiar with in daily life.
This MOOC is the first step of a series of courses for engineering simulation. It aims to provide
necessary background of physics for every engineer to understand and use simulation in Mechanics.
Before conducting simulation for complex mechanical problems by
computational solver, it s essentialfor you to master the physics behinds them.
For example:
How deformation is descripted?
What s the internal force in materials under deformation?
Why there are different materials models and how to choose from them?
Or even how the problem can be solved numerically?
All such background knowledge is the keystone of
mechanical simulation and it can be heavily related to mathematics.
In this course, instead of throwing out theories and mathematical formulations,
we will use images, animations, and examples related to daily life and modern industry
to explain the concepts, so that the underlying physics is better understood.
To start with, let s define the scope of our course. We are going to learn about
the macroscopic behavior of a structure or material. We will be looking for the motion,
deformation, stress and strain of a structure as a wholistic body.
On the other side, if we zoom in to the microstructure of any material,
the molecular structure is exposed. The study of such microstructure is called
Molecular or Quantum mechanics, which falls out of the focus of this course.
What is discussed in this course will be continuum mechanics,
as implied by the name, we treat the material as continuous mass instead of discrete atoms.
As for continuum bodies, there are two main types of them in mechanics.
One is fluid, which studies liquids and gases. The feature of fluids is they cannot
resist deformation force, it moves, or flows under the action of the force.
Another type of body is solid. Solids can resist deformation force while at
rest. And solid bodies are what we will discuss in this course.
In Mechanics, we can treat a solid body as a rigid body, or we can treat it as a flexible body.
For rigid bodies, they do not deform under the action of applied forces. The study of rigid
bodies looks for the movement of systems and reaction forces from the movement.
For example, here, the two cars are treated as rigid bodies to track their relative movement.
Or, these gears are treated as rigid bodies to find the
needed turning force for this rigid mechanism.
On the other side, when a body is treated as a flexible body.
We look for material deformation of the body under external loads.
For example,?the deformation of a car after a strong impact
Or the gear teeth deformation cause by contact between different gears.
Most of this course will focus on flexile bodies.