Mechanical Systems: Analysis of Engine Crane, Chair Structure, Industrial Robot, Ski, Sign Post and Diving Board

The group coursework analyzes the structure of various mechanical systems such as engine crane, chair structure, industrial robot, ski, sign post, and diving board. It includes calculations of sectional properties, maximum bending stress, and possible beam deflection. The analysis would really help in design processes in the real world and choosing materials that can withstand the stresses involved. Subject: Mechanical Systems, Course Code: N/A, Course Name: N/A, College/University: N/A

Running head: MECHANICAL SYSTEMS 1
Mechanical Systems
Name
Institution Affiliation
1. ENGINE CRANE.
.Description and functions
The engine crane is a familiar tool that is used to remove or install
diesel engines and gasoline engines in crowded and small vehicle
compartments. This mechanical structure is commonly found in
repair workshops and sometimes it is known as engine hoist.
Photo of the engine crane

MECHANICAL SYSTEMS 2
Photo and sketches of an element from the engine crane
Element ABC selected from the crane engine
A 3ft B 5ft C
Calculating the sectional property of the element
A 3ft B 5ft C

MECHANICAL SYSTEMS 3
200lb
Taking reaction about point A;
FA = FB – FC =0
FA = FC -FB
Taking the moments about point A;
 MA = 3ft (FB) – 8ft (200lb)
0 = 3ft (FB) – 1600ft-lb
FB = 3
1600
=533.33lb
FA = FC -FB
= 200-533.33
=- 333.33lb
Estimate of the maximum bending stress throughout the element
To estimate the maximum bending stress throughout the entire system, we
constructed the shear diagram of the element.

MECHANICAL SYSTEMS 4
Maximum bending stress occurs at B according to our sheer diagram;
Maximum Stress = -333.33 -200
= 533.33 lb
Estimate the possible place where maximum beam deflection occurs.
From the shear diagram constructed for the element using the forces acting
on it, it can be seen that point B is the place where maximum beam
deflection is going to be experience in the system.
2. The Chair Structure.
Description and functions
A chair is simple mechanical structure that is designed for people to seat on
it and is used all over the word. There are various types of chairs in the
universe. The main function of the chair is to provide support to the
individual(s) seating on it.
Photos of a chair

MECHANICAL SYSTEMS 5
Photo and element
Element ABC below
A 1.5ft B 1.5ft c
Calculating the sectional properties of the element
Taking reaction about point A,
FA = FB – FC =0
FA = FC -FB
Taking moments about point A,
 MA = 1.5ft (FB) – 3ft (150lb)
0 = 1.5ft (FB) – 450ft-lb

MECHANICAL SYSTEMS 6
FB = 5.1
450
=300lb
FA = FC -FB
= 150-300
= -150lb
To estimate the maximum bending stress throughout the entire system, we
constructed the shear diagram of the element.
Shear diagram of the free body diagram of the element.
Maximum bending stress occurs at B according to our sheer diagram;
Maximum Stress = 300 -150

MECHANICAL SYSTEMS 7
= 150lb
Estimation of the possible place where maximum beam deflection occurs
From the shear diagram constructed for the element using the forces acting
on it, it can be seen that point B is the place where maximum beam
deflection is going to be experience in the system.
3. Industrial robot to hold object.
Description and functions
Robots are mechanical systems that are used to perform various physical
activities by regulating physical quantities. Robots range in simplicity and
automation. Industrial robots are used in situations where human personnel
will be inefficient or in scenario where toxic gases and other hazards are
involved therefore the safety of the human personnel is compromised. The
functions of the robots range according to the specifications of the design.
The industrial robot to hold objects has the sole responsibility of providing
support to the object being held.
Photo of a robot

MECHANICAL SYSTEMS 8
Photo and sketch of an element from the system
A 10 in B 50in C
Calculating the sectional properties of the element
Taking reaction about point A,
FA = FB – FC =0
FA = FC -FB Let FC = 20lb
Taking moments about point A,
 MA = 10in (FB) – 60in (20lb)
0 = 10in (FB) – 100in-lb
FB = 10
1200
=120lb
FA = FC -FB
= 20-120
= -100lb`

MECHANICAL SYSTEMS 9
To estimate the maximum bending stress throughout the entire system, we
constructed the shear diagram of the element.
Shear diagram of the free body diagram of the element.
Maximum bending stress occurs at B according to our sheer diagram;
Maximum Stress = 120-100

MECHANICAL SYSTEMS 10
= 20lb
Estimation of the possible place where maximum beam deflection occurs
From the shear diagram constructed for the element using the forces acting
on it, it can be seen that point B is the place where maximum beam
deflection is going to be experience in the system.
4. The Ski
Description and functions
Snow skiing has been both a means of transport and recreational activity for
so long in cold regions of the world where ice covers very large tracts of
land. The ski is used by people to smoothly glide through the snow. The ski
supports the wait of the person to enable movement over the snow. The ski
comes in different sizes but the general shape is similar in all of the different
designs.
Photo of the Ski

MECHANICAL SYSTEMS 11
Photo and Sketch of an element from the system
Sketch
3ft C
A B C D
15ft 3ft 1.5ft
Taking about point A,
FA = W +W +FB – 180
Taking moments about A,
6FB =1.5(180) +540 +810
FB =900÷6
=150
FA = FC -FB

MECHANICAL SYSTEMS 12
=150-150
=0
To estimate the maximum bending stress throughout the entire system, we
constructed the shear diagram of the element.
Shear diagram of the free body diagram of the element.
Bending stress at B according to our sheer diagram;
Maximum Stress = 180 -180
= 0
This shows that the weight is uniformly distributed and therefore stress is
equal along the whole system.
Estimation of the possible place where maximum beam deflection occurs

MECHANICAL SYSTEMS 13
From the shear diagram constructed for the element using the forces acting
on it, it can be seen that deflection in the beam will be uniform along the
whole ski.
5. The sign post.
Description and Functions
A sign post is a mechanical structure that is mostly found beside
roads and it is uased to pass given information. It is common to come across
signposts that give direction or advertise a certain product. The signpost has
to have sufficient support to withstand the varying wind pressure.
Photo of a sign post

MECHANICAL SYSTEMS 14
Photo and Sketch of an element from the system.
C
7.5ft
B
4ft
A
Calculating the sectional properties of the element
Area = L * W
=5 * 3
=15 ft2

MECHANICAL SYSTEMS 15
1 ft2 =7 lb.
15 ft2=15 *7 = 105lb
Taking reaction about point A,
FA = FB – FC =0
FA = FC -FB
Taking moments about point A,
 MA = 4ft (FB) – 3ft (105lb)
0 = 4ft (FB) – 787.5ft-lb
FB = 4
5.787
=196.875lb
FA = FC -FB
= 105 -196.875
= -91.875lb
To estimate the maximum bending stress throughout the entire system, we
constructed the shear diagram of the element.
Shear diagram of the free body diagram of the element.
Maximum bending stress occurs at B according to our sheer diagram;

MECHANICAL SYSTEMS 16
Maximum Stress = 196.875 -105
= 91.875.
Estimation of the possible place where maximum beam deflection occurs
From the shear diagram constructed for the element using the forces acting
on it, it can be seen that point B is the place where maximum beam
deflection is going to be experience in the system.
6. The Diving Board
Description and functions
The diving board is a mechanical system that is commonly found at
swimming facilities to help swimmers and divers to jump in water. The board
must have sufficient mechanical strength to withstand the varying weight of
those using it.
Photos of a diving board
Photo and sketch of an element from the system

MECHANICAL SYSTEMS 17
A 1.5m B 2.5m C
Calculating the sectional property of the element
A 1.5m B 2.5m C
FA = FC -FB
120
Taking reaction about point A;
FA = FB – FC =0
FA = FC -FB
Taking the moments about point A;
 MA = 1.5m (FB) – 4m (120lb)
0 = 1.5m (FB) – 480m-lb
FB = 5.1
480
=320
FA = FC -FB
= 200-320
= -80lb
Estimation of the maximum bending stress.

MECHANICAL SYSTEMS 18
To estimate the maximum bending stress throughout the entire system, we
constructed the shear diagram of the element.
Shear diagram of the free body diagram of the element.
Maximum bending stress occurs at B according to our sheer diagram;
Maximum Stress = 320-120
= 80lb
Estimation of the possible place where maximum beam deflection occurs
From the shear diagram constructed for the element using the forces acting
on it, it can be seen that point B is the place where maximum beam
deflection is going to be experience in the system.
SUMMARY OF GROUP COURSEWORK

MECHANICAL SYSTEMS 19
The group course work was touching on various mechanical systems that we
come across in our day to day activities. The cause work helped us to study
structure analysis of these common systems. In this course work, we were
able to identify the forces acting on these systems and calculated their
moments. The analysis would really help in design processes in real word
and choosing materials that can withstand the stresses involved. The
analysis was performed assuming that the parts were rigid and the system is
in equilibrium.
CONCLUSION
The group members were cooperative and showed a good attitude towards the topic. I
commend on the contribution from each member that enabled this group course work to
be a success.

MECHANICAL SYSTEMS 20
Reference
Hernandez, E. a. (2014). A model-based observer for state and stress
estimation in structural and mechanical systems. New York: New York
Press.
Tapie, R. a. (2017). Stresses in Mechanical Systems. New York: Trademark
Office.