CE 102
MECHANICS OF MATERIALS
INSTRUCTOR:
ENGR. SICENIO D. ABERA JR.
HISTORICAL DEVELOPMENT
▪ Beginning of the seventeenth century (17th century)
Galileo Galilei performed experiments to study the
effects of loads on rods and beams made of various
materials
▪ Beginning of the nineteenth century (19th century)
Experimental methods for testing materials were vastly
improved. At that time many experimental and
theoretical studies in this subject were undertaken,
primarily in France, by such notables as Saint-Venant,
Poisson, Lamé, and Navier
1.1 FUNDAMENTAL AREAS OF
ENGINEERING MECHANICS
Statics - deals with the analysis of bodies in equilibrium,
where the resultant forces and moments are zero, and the
bodies are either at rest or moving with constant velocity.
Dynamics - focuses on the study of bodies in motion where
acceleration is present, examining the relationship between
forces and the resulting motion.
Strength of Materials - concerns the behavior of solid
bodies subjected to external loads, specifically analyzing the
internal stresses, strains, and deformations that develop as
a result of these applied forces
MECHANICS OF MATERIALS
▪ is a branch of mechanics that studies the internal effects of
stress and strain in a solid body.
Stress - is associated with the strength of the material
from which the body is made.
Strain - is a measure of the deformation of the body.
A thorough understanding of the fundamentals of this subject
is of vital importance for the design of any machine or
structure, because many of the formulas and rules of design
cited in engineering codes are based upon the principles of this
subject.
MECHANICS OF MATERIALS
▪ Strength of materials, also known as mechanics of materials,
is the study of how solid objects respond to applied forces.
▪ It defines the ability of a material to withstand an applied
load without failure or plastic deformation.
▪ Key concepts include ultimate strength (the maximum stress
before fracturing) and yield strength (the stress at which
permanent deformation begins). This field examines the
relationship between external loads and the resulting
deformation or changes in material dimensions
MECHANICS OF MATERIALS
STATICS AND DYNAMICS
MECHANICS OF MATERIALS
Body
Ideal/Rigid
Real/Deformable
Force
External Effects
Internal Effects
Analysis
FBD, Equations of Equilibrium
FBD, Equations of Equilibrium,
Deformation Diagrams
Focus
Identification of Loads Acting on a
body
Determining the Strength and
Rigidity of the Body
1.1.1 WHY ARE THE INTERNAL EFFECTS
IN AN OBJECT IMPORTANT?
Strength:
a. Is the object strong enough to withstand loads that
will be applied to it?
b. Will it break or fracture?
c. Will it continue to perform properly under
repeated/cyclic loadings?
Stiffness:
a. Will the object deflect or deform considerably that it
can no longer perform its intended use/purpose?
1.1.1 WHY ARE THE INTERNAL EFFECTS
IN AN OBJECT IMPORTANT?
Stability:
a. Will the object suddenly bend or buckle out of shape
at some elevated load so that it can no longer continue
to perform its function?
1.1.1 WHY ARE THE INTERNAL EFFECTS
IN AN OBJECT IMPORTANT?
AS CIVIL ENGINEERS:
We need to proactively,
1. Select the proper materials
2. Specify the dimension
REVIEW OF STATIC EQUILIBRIUM
EQUILIBRIUM
OF DEFORMABLE BODIES
CONCEPT OF LOAD AND
INTERNAL RESISTANCE
The external loads acting
on a deformable body are
the known force and
moments that are applied
to the body.
They may be classified in
four categories, or types.
These types, together
with their appropriate
dimensions, are
SUPPORT REACTIONS
RESULTANT FORCE AND RESULTANT MOMENTS
SHEAR FORCES, BENDING MOMENT, NORMAL FORCE
EXAMPLE PROBLEMS
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