1. Engineering Applications using MATLAB
MATLAB Tutorials
Session VI
Engineering Applications using MATLAB
Rajeev Madazhy
Dept of Mechanical Engineering
LSU

2. Last Session…. Solving Double Integrals
Ordinary Differential Equations
Examples of ODE using MATLAB….
Mention of DDE’s

3. Session VI Outline…. Engineering Applications using MATLAB….
Solving non linear differential equations
Algorithm analysis for four bar linkage problem
Other mechanical problems

4. Solving non-linear Diff Equation….
Same as linear differential equations (use ode45)
Incorporate differences in the function
Consider the previous example of spring-mass-damper system
let there be an external force of 0.1*sin(w*t) where w is the
frequency of the input and the value of c and k varies as follows
C=1 for x(1)>0.5m/s and 5 for x(1)<=0.5m/s
K=10 for x(2)>=-0.25m and 20 for x(2)<-0.25

5. Function….

6. Command window….

7. Output….

8. Output….

9. Example 2: Four Bar Linkage….C y B   D  A x

10. The lengths of AB, BC, CD, DA are known
Algorithm analysis….
The lengths of AB, BC, CD, DA are known
To determine the coordinate (x, y) of point C at each
rotation angle of ABD or .
Basic formula. B c a C A b

11. Cont….
Step 1: Calculate length of BD
Step 2: Calculate angle
Step 3: Calculate angle
Step 4: The coordinate of point C is as follows:

12. Cont….
( If 0< <pi )
( If pi < <2pi )

13. MATLAB program….

14. MATLAB program….

15. MATLAB program….

16. MATLAB program….

17. Animated output….

18. Moving block in an inclined plane….
Moving object from (x1,y1) to (x2,y2). The friction
coefficient is =0.1. The starting velocity at 1 is v1.
Calculate v2 (velocity at 2), t (time), and a (acceleration) N  mg
mgsin
mgcos N
(x1,y1) v1
(x2,y2) v2

19. MATLAB Program….

20. Output….

21. Determining Diameter of the pipe from the flow rate….Q

22. Fountain.m

23. Fountain.m cont….

24. Piping.m

25. Piping.m cont…

26. Recap…. What have we learnt today?
Engineering Applications using MATLAB….
Solving non linear differential equations
Algorithm analysis for four bar linkage problem
Other mechanical problems

27. Thank You