Lecture 1
defining mechanical engineering
•
very broad
"
"
°
A mechanical devices, and realizes new products optimizes existing technologies
and
engineer designs .
examples : cars (engines designs) Shavers , materials to enhance force luggage belts
°
, . ,
°
Subareas of mechanical engineering
-
completional and experimental mechanics
1. mechanics of materials
2.
Microsystems
3.
polymer Technology
-
Thermofluid engineering
1.
energy technology
2. power & flow
-
Dynamical system design
1. control systems technology
& control
2.
dynamics
simple tools
•
example 1- ladder
% '
e
smooth← ¢ t
when problem take it of salt ( is ladder of realistic ? )
given with a grain 00kg
°
a
mg;§g¥gg_
a
waeey →
y start by drawing a schematic diagram with forces
°
:
FF few
%
.
as
Always (when working with arrows) explicitly state which direction
u
°
e •
mm, ,,,
µ=µ
, ⇐
↳ grass
is positive , a.
¥
problem EÉ= 0 Fx
,
In a static 0 Fy 0
•
: = =
,
Fw , -
Fµz =
0
FN , FNZ- -
Fwz =
0
•
for normal forces friction forces
, ,
drawn directions are arbitrary
•
must calculate torque around a certain point .
Given clockwise is +,
ace forces acting this point have IT 0
torque
-
=
on no
Torque force ✗ arm T-z.EE Fazl Sina
-
=
Cosa -
•
Introduce variables to see dependencies + Fwlcosa = 0
The arm is the projection ( perpendicular to force direction )
•
°
Given the wall is smooth FNz<< FN , such that Faiz can be approximated by
, ,
0
-
this leaves you with 3 equations 813 unknowns
FN , Fz 30×9.01 204N
g
=
=
M -
= =
F-w-i-FNz-T-z-E.ee/cosa/esinA
↳ not
dependant on length
•
example 2- nut cracker
•
the three parts need to be separated hand
-€ each part is in equilibrium
-
-
Top handle :
(IIF )
/ Fnut
¥
En Faxee + Fnut thanD= 0
nuy
-
↳
I
'
+
-
Fnutt , +F
"
hand
•
↳
(L ,
+ Lz ) = 0 ( T) Fane Fnut Fane
Fnut =
I •
F- hand
+
Faxee =-3 f-hand
°
To determine the most efficient nutcracker , L , must
be small and Lz large . F- hand
for the given measurements its amplification of 4
•
an
, dirt
work done power F- at
:
ddt-C-w-7-d-d-IF.xt-dd-E.xtdd-E-T-W-F.gg/x-T
Work :
Using aforceto displace
object
•
an
>
displacement
the force
•
same was applied
Work energy principle overtime :dd¥=0
°
-
•
the best -
case scenario occurs when there's no energy losses
P=F¥=F°v
According
W-in-W-out-W-in-T-inoh-X.in
°
to the work principle ,
energy
-
example 1: pallet Jack
•
source
Trout -_ Fout ☐
✗ out
•
Xo =
0cm
side Wont
machine
T-outAXout-F.no/-Xin Win
°
✗ out =
✗ final -
✗0--15-8=7 cm
eoad
Transmission ratio i=F
" ☐ " "t
• =
side
time :
°
Fout : A- ✗ in 4.7s → radius
times levers /
pulled 05
04cm
✗ in =P -3602
° . t
- -
↳ from degreeto
radian
°
t-in-it-out-i.im?j-wei9ht
^
84cm
%
.
defining mechanical engineering
•
very broad
"
"
°
A mechanical devices, and realizes new products optimizes existing technologies
and
engineer designs .
examples : cars (engines designs) Shavers , materials to enhance force luggage belts
°
, . ,
°
Subareas of mechanical engineering
-
completional and experimental mechanics
1. mechanics of materials
2.
Microsystems
3.
polymer Technology
-
Thermofluid engineering
1.
energy technology
2. power & flow
-
Dynamical system design
1. control systems technology
& control
2.
dynamics
simple tools
•
example 1- ladder
% '
e
smooth← ¢ t
when problem take it of salt ( is ladder of realistic ? )
given with a grain 00kg
°
a
mg;§g¥gg_
a
waeey →
y start by drawing a schematic diagram with forces
°
:
FF few
%
.
as
Always (when working with arrows) explicitly state which direction
u
°
e •
mm, ,,,
µ=µ
, ⇐
↳ grass
is positive , a.
¥
problem EÉ= 0 Fx
,
In a static 0 Fy 0
•
: = =
,
Fw , -
Fµz =
0
FN , FNZ- -
Fwz =
0
•
for normal forces friction forces
, ,
drawn directions are arbitrary
•
must calculate torque around a certain point .
Given clockwise is +,
ace forces acting this point have IT 0
torque
-
=
on no
Torque force ✗ arm T-z.EE Fazl Sina
-
=
Cosa -
•
Introduce variables to see dependencies + Fwlcosa = 0
The arm is the projection ( perpendicular to force direction )
•
°
Given the wall is smooth FNz<< FN , such that Faiz can be approximated by
, ,
0
-
this leaves you with 3 equations 813 unknowns
FN , Fz 30×9.01 204N
g
=
=
M -
= =
F-w-i-FNz-T-z-E.ee/cosa/esinA
↳ not
dependant on length
•
example 2- nut cracker
•
the three parts need to be separated hand
-€ each part is in equilibrium
-
-
Top handle :
(IIF )
/ Fnut
¥
En Faxee + Fnut thanD= 0
nuy
-
↳
I
'
+
-
Fnutt , +F
"
hand
•
↳
(L ,
+ Lz ) = 0 ( T) Fane Fnut Fane
Fnut =
I •
F- hand
+
Faxee =-3 f-hand
°
To determine the most efficient nutcracker , L , must
be small and Lz large . F- hand
for the given measurements its amplification of 4
•
an
, dirt
work done power F- at
:
ddt-C-w-7-d-d-IF.xt-dd-E.xtdd-E-T-W-F.gg/x-T
Work :
Using aforceto displace
object
•
an
>
displacement
the force
•
same was applied
Work energy principle overtime :dd¥=0
°
-
•
the best -
case scenario occurs when there's no energy losses
P=F¥=F°v
According
W-in-W-out-W-in-T-inoh-X.in
°
to the work principle ,
energy
-
example 1: pallet Jack
•
source
Trout -_ Fout ☐
✗ out
•
Xo =
0cm
side Wont
machine
T-outAXout-F.no/-Xin Win
°
✗ out =
✗ final -
✗0--15-8=7 cm
eoad
Transmission ratio i=F
" ☐ " "t
• =
side
time :
°
Fout : A- ✗ in 4.7s → radius
times levers /
pulled 05
04cm
✗ in =P -3602
° . t
- -
↳ from degreeto
radian
°
t-in-it-out-i.im?j-wei9ht
^
84cm
%
.
