MAPÚA UNIVERSITY

School of Mechanical and Manufacturing

Engineering

Laboratory Experiment 1.2

Tensile Test of Reinforcing Steel Bar

Name: Apora, Erol Josef S.

Student Number: 2020110404
Course and Section: ME136P-2 – E01

Prof. Jennifer Valdez

Instructor
ABSTRACT
The tensile strength of a substance is considered to identify the point at which it switches from
elastic to permanent deformation. It is found by analyzing the amount of strain required to
disassemble the component. The tensile strength of a metal not only tells how effectively an alloy
can be expanded without becoming brittle, but it also informs how much power a specific piece of
material can withstand before snapping. Despite being stretched to its maximum permissible length
and fully thinned conceivable, the cylindrical shape of the test object remains intact. The specimen
forms a neck as a result of putting the maximum force to it. As a result, the learner had a better
understanding of the circumstance. Two separate methodologies were used to assess participants'
understanding of the characteristics of materials that change when subjected to tensile stress, such
as elasticity, plasticity, snogging, and ultimate failure. the ability to recognize that different natural
variables will react to stress in various ways.
AIM
• Determination of the suitability of reinforcing steel bars for concrete reinforcement by
performance of tensile test using ASTM Designation A370 and grade of steel bars.
• To determine the grade of steel bars.
INTRODUCTION
Tension is formed when something is stretched beyond than it would normally be. A rope
fastened to a rooftop with a weight dangling from the end that is free is one illustration of this.
Gravity's downward pull and motion at the connection location on the rooftop are both variables
that contribute to the cable's tension. The amount of tension that it can withstand before giving
way is directly proportional to its tensile strength. It is usual practice to replace a material's
elasticity/plasticity boundary with its tensile strength. It is computed by estimating the maximal
force required to cause a fracture in the material at the spot where it is found. Tensile strength is
determined by the amount of stress that an element or metallic component can withstand before
snapping, as well as the duration of time that it can be stretched before the combination or metal
begins to deteriorate. As a result, knowing tensile toughness is critical for building projects as well
as human health and safety.
METHOD
The answer to the first question is that a metal's yield strength is critical in engineering design.
The answer to the first question is as follows. The phrase "yield strength" refers to the highest
amount of stress that a material can withstand before deforming plastically, and it acts as an
indication of this maximum level of stress. This stress is an excellent way for evaluating the limit
of proportionality; it emerges when a component exhibits a certain continuous curve. Yield
strength is a critical component in the world of engineering. Components must be built to withstand
the loads that will be applied to them to prevent plastic deformation. While creating a structure, it
is critical for an engineer to use a material with a high yield strength. The elastic limit refers to the
tension that arises when a material begins to deform irreversibly. When elastic deformation gives
way to plastic deformation, the material has attained its maximum strength. Materials have a
propensity to return to its initial shape if they are devoid of any loads or strains. Furthermore, to
answer the question of why it is necessary to establish the gage length whenever attempting to
calculate the percentage of elongation, the reason is that percentage elongation is not an accurate
indication of ductility because stretching is not consistent along the entire gage length and, as a
result, is greatest in the middle of the neck. This is why determining the gage length is critical. As
a result, whenever an elongation % is stated, the gage length should also be provided.
Since metals and plastics are the only materials that can be properly utilized for wedge grips,
analyzing fragile materials should not be done with wedge grips. When the pressure is increased,
the wedge grip tightens, increasing the likelihood that the sensitive component would fracture as
a result of the increased pressure. Finally, the yield point is the amount of stress at which a material
changes condition from elastic to plastic. Yield strength, on the other hand, is the degree of stress
at which a material transitions from elastic to plastic. The feature known as yield strength reflects
the upper limit of a material's elastic capabilities.
RESULT AND DISCUSSION
Specimen Label 1 2
Classification Plain Deformed
Length 505 mm 520 mm
Weight 0.8 kg 0.8 kg
Gage Length 200m 200 mm
Final Length 527 mm 596 mm
Max Force 105.219 KN 104.813 KN
Max Stress 523.315 Mpa 521.245 Mpa
Break Stress 180.510 Mpa 005.02 Mpa
Table 1: Data Gathered from Experiment

The force appears to be growing fast, which is consistent with the experiment results. If the
force elongation graph shows a perfect line that matches to the elongation of the specimen, the
material is elastic. The findings of this test show that when one near the end of the elasticity area,
there is a considerable drop in force. Plastic deformation is indicated by the existence of a stretched
yield point in a material. Because this limit has been achieved, the force seems to be virtually
constant, indicating a shift. The Lüder's effect happens when the pressure rises after a certain
amount of strain, known as the Lüder's strain. This exhibits strain stiffening and complicates the
distortion. To stretch it out and lower its thickness, the measuring equipment is exposed to the
highest force it can withstand across its whole length. If the component being tested is subjected
to extreme pressure, a bottleneck forms.

CONCLUSIONS
Questions:
1.) Why would an engineer be interested in the yield strength of a metal for a particular
reason?
The ability of a material to withstand higher loads without cracking or bending is referred
to as "yield strength," and it is measured in megapascals (Mpa). At the end of the day, it all comes
down to conducting an analysis to decide how far you can go. The critical pressure is the pressure
at which a material first begins to exhibit variable modulus. Throughout the process of identifying
the material, an engineer must pay close attention to the stiffness of the material. This is due to the
stiffness of the material revealing whether or not the material can withstand the external factors
being formed.
2.) Distinguish clearly between proportional and elastic limit.
The elastic limit of a material is the point at which it retains its integrity even when
subjected to the maximum force that can be applied to it. At this moment, the elasticity of a material
is measured. When the electricity is turned off, the material will, for the most part, retain its
previous shape. Whatever the situation may be, imagine it approaches and then surpasses the limit
of its plastic deformation. Taking everything into account, it will not revert to its previous structure
at this time, and it will reach the yield point, which is the point at which its definitive strength may
be determined.

3.) How seriously are the results of tension test of reinforcement bar affected if the specimen
dimensions vary a little from the standard?
During the tension test, the support bar extended out, causing the measure's breadth to
narrow and its length to lengthen. This was the result of the exam. The overall stiffness of the
material accounts for the very slight variance in appearance. For example, the ability to produce
something known as a yield point is the most extreme power that carbon steel can be blessed with.
This precise course of action fully demonstrates the material's adaptability, making it the greatest
alternative accessible.
4.) Why is necessary to state the gage length when reporting the percentage of elongation?
When calculating the rate of extension, the gauge length is an extremely important factor
that must be considered. Tensile tests cause materials to distort in proportion to one another as they
stretch more and more until they reach their maximum length. This will be repeated till the test is
finished. After demonstrating that it is capable of surpassing the limit, the new gauge length may
be molded and a precise estimate of the strength created. As a result, its behavior grows
progressively exaggerated as it near the point when it will cave in. In the region surrounding the
producing neck, reasonable estimations on the ideal gauge length are available.
5.) Are wedge grips suitable for tests of brittle materials? Explain
It is not suggested to utilize materials that are prone to cracking when developing wedge
grips. Wedge grips are designed to keep a material's tightness even as the heap increases,
preventing slipping during tensile testing. This is done in order to avoid slippage. The fact that the
bulk of the metal is flexible and malleable means that it will expand with time, resulting in a
decrease in gauge length. This is due to the fact that the majority of the metal is flexible and
malleable. Brittle materials, on the other hand, are sensitive and cannot withstand stresses that are
greater than their capacity.
6.) Distinguish between yield point and yield strength?
When used in the context of a stress-strain curve, the phrase "yield point" refers to a
location that signals the end of the material's elastic nature. As a direct result, the force exerted by
the material has decreased significantly, and the property of its ultimate strength is approaching.
On the other hand, yield strength is a property correlation that shows a material's ability to
withstand a load without deformation while preserving its original dimensions. This capacity is
determined by the material's ability to retain its original form after being exposed to a load.
REFERENCES