     

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ME 481 - H06 Name ________________________

Use generalized coordinates {q} and joint constraints {

} for the slider crank shown below.

 x y

 x

2

2

2

3

 y

 x y

3

3

4

4

4

 

2

 r

3

2

 

 r

4

3

 

4







    r

4

2

   

3

C r

3

1

2

A

B

C

2

 y

4

4

2 t



 y

2

A

2

A x

2

A

1

2 y

1

B

2 x

1

B

B

3

G

3 y

3

G

3 x

3

3 C

C

3

C

4

4 y

4 x

4

AB = R = 0.985 inch

BC = L = 4.33 inch

BG

3

= 1.1 inch

G

2

is at A

2

(balanced crank)

G

3

is on centerline of link 3

G

4

is at C

4

(simple piston model) x

2

axis along centerline of link 2 x

3

axis along centerline of link 3

2

= 1000 rpm CCW constant

2

4

A 

0

0

C 

0

0

 

'

2

 

1

A

B 

0

0

R

0

BLUEPRINT INFORMATION

 

'

3

B 

BG

3

0

 

3

'

C 

L BG

3

0 example for B3

   

3 3

  

3 3

'

B

 

3

 cos sin

3

3

 sin

3 cos

3

ME 481 - H06 Name ________________________

1) Evaluate residuals {

} for rough estimates of generalized coordinates {q} at t = 0.005 sec shown below. Comment on the relative precision of {

} versus {q}.

0

0

0 .

4363

2 .

0 inch inch rad inch

( 25

)

__________ _____

__________ _____

__________ _____

__________ _____

0 .

5

0 .

1745

0

5 .

0

0 rad inch rad inch inch

( 0

(

10

)

)

__________ _____

__________ _____

__________ _____

__________ _____

__________ _____

2) Use geometric equations to determine better estimates for {q} at time t = 0.005 sec. Then evaluate new residuals. Comment on precision of {q} and {

} between parts 1) and 2).

0

0 inch inch

2 t

__________

__________ _____

__________ _____

__________ _____

__________ _____

__________ _____

 

__________ _____

__________ _____

__________ _____

0

0 inch rad ( 0

)

__________ _____

__________ _____

__________ _____

__________ _____

__________ _____

3) Evaluate the Jacobian

  q

for your better estimate of {q} at t = 0.005 sec.

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______

______

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______

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______

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______

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______

______

______

______

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______

______

______

______

______

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ME 481 - H06 Name ________________________

4) Use your code to perform a Newton-Raphson position solution at t = 0.010 sec. Calculate piston position x

4

and determinant of the Jacobian. Validate with geometric equations. x

4

(Newton-Raphson) ____________ det

  q

____________ x

4

(geometric) ____________

5) Compute piston velocity x

4

and acceleration right-hand-side (RHS) vectors

 

and

 

 x 

4

at t = 0.010 sec using a matrix solution with

. Validate with geometric equations. x

4

(matrix) ____________

 x 

4

(matrix) ____________ x

4

(geometric) ____________  x 

4

(geometric) ____________

EXTRA CREDIT

Place a loop around your solution for part 5) using 0 ≤ t ≤ 0.06 sec and provide MATLAB graphs for piston position x

4

and acceleration  x 

4

as functions of crank angle

2

. Validate using results from geometric equations on the same MATLAB graphs.

EXTRA EXTRA CREDIT

Modify your slider crank code for part 5) to analyze the four bar in Notes_04_05. This should only require modifying the last three rows in your constraint vector, your Jacobian matrix and your acceleration RHS vector. use

2

= 65° validation

= 13.151°

3

2

3

= 10 rad/sec CW

= _______________

  

  

3

2

= 2 rad/sec

2

CCW

= +7.0627 rad/sec

2

4

= -65.173°

4

= -5.3533 rad/sec

  

4

= _______________

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