When the sample was removed, even after experiencing a large strain, the sample nearly returned its original length. Low-density polyethylene, polylactic acid and Dynaflex exhibited different mechanical behavior.
The result was a large amount of plastic deformation as shown in Figure 1. Other methods used to ensure accurate strain measurements include a strain gauge or a video extensometer to monitor the sample during the test. In addition, defects were present in many of the samples.
Dynaflex almost entirely displayed elastic behavior as shown in Figure 5. No necking or ductile behavior was exhibited.
First, the detailed processing conditions such as temperature and injection pressure should be obtained for each specimen because its final mechanical properties are highly dependent on its processing Tensile test polyethylene and polystyrene. The combination of high ultimate tensile strength and high elongation leads to materials of high toughness.
For this test, plastic samples are either machined from stock shapes or injection molded. This graph can be seen in Figure 5 of the "Results" section. Double gate PS example. The force per unit area MPa or psi required to break a material in such a manner is the ultimate tensile strength or tensile strength at break.
Additionally, when loading samples into the tester, it was imperative that the samples were properly aligned within the grips. This weld line acted as a defect and failure occurred at this location. There were multiple potential sources of error for this experiment.
The tensile and compressive moduli are often very close for metals. First, each of samples were made using different processing conditions compared to the literature value samples, and so the values will be slightly different.
Additionally, a video extensometer should be used to accurately monitor the strain. From these sources of error, several actions could be taken to improve this experiment in the future.
Tensile Property Testing of Plastics Ultimate Tensile Strength The ability to resist breaking under tensile stress is one of the most important and widely measured properties of materials used in structural applications.
Tensile Elongation The ultimate elongation of an engineering material is the percentage increase in length that occurs before it breaks under tension.
A high tensile modulus means that the material is rigid - more stress is required to produce a given amnount of strain. The figure below, from Quadrant Engineering Plastic Productsshows the test geometry. Second, only samples containing no defects should be used for tensile testing.
Polylactic acid exhibited brittle failure as shown in Figure 4. If five or more specimens were tested for each sample, the data obtained would be more reliable. Figure 2 in the "Results" section shows a nearly linear increase in stress until failure.
In addition, there were different processing conditions between the different samples used in this experiment, and the time they were made appeared to have an impact on their mechanical properties.
The values reported in the ASTM D and ISO tests in general do not vary significantly and either test will provide good results early in the material selection process.
Tensile Modulus of Elasticity The tensile modulus is the ratio of stress to elastic strain in tension. Later, the stress decreased due to necking and transitioning into plastic deformation.
Intermediate failure is characterized by some necking and then immediate failure. Low-density polyethylene exhibited intermediate failure as shown in Figure 3.
Figure 3 in the "Results" section shows a linear behavior correlating with the elastic region of the stress-strain curve. In polymers, the tensile modulus and compressive modulus can be close or may vary widely.
In Figure 1 in the "Results" section, this stress-strain behavior is characterized by an initial linear increase in stress in the elastic region.
Some showed microcracks, others showed air bubbles within the gage length. Failure was not observed because the sample slipped out of the grips during testing. After the reduction in cross-sectional area caused by necking, the stress linearly increased until failure.The material that has lowest ultimate tensile strength is Low Density Polyethylene (LDPE) with 8.
it has been proved that Polystyrene (PS) has the highest ultimate tensile strength before it broke when it been stretched with value of Measure area under the stress versus strain curve using Plarimeter or other methods?/5(2).
PDF | On Sep 1,Jelena Milisavljević and others published TENSILE TESTING FOR DIFFERENT TYPES OF POLYMERS. Below is an essay on "Tensile Testing" from Anti Essays, your source for research papers, essays, and term paper examples.
DEN -‐ Polyethylene and Polystyrene. Tensile Strength Tester, Tensile Testing Machine - Materials Testing Machines - Labthink. Tensile Strength of different plastics. Chloe Arnold, Chris Lan, Daniel Amador. ENGR45, F, SRJC. • Polyethylene (two forms found) – High density - Notebook • Plastics were not strong enough.
– Ripped before any measurement. Different Way to Test • The string machine. – Slightly altered the fixture for fitness and. Deformability and tensile strength of expanded polystyrene under short-term loading.
The present paper addresses the problems of deformability and tensile strength of EPS under short-term loading and optimization of sample geometry (thickness) for determining these characteristics. Comparison of tensile test results obtained for modulus.Download