Materials in Practice CP4088/CP8011|
By Clinton Chang|
This experiment is to find out the tensile strength of different plastic materials. The four plastic materials used are General Purpose Polystyrene (GPPS), High Impact Polystyrene (HIPS), High Density Polyethylene (HDPE) and Polypropylene (PP). By using three samples from each plastic material type, we are able to obtain the mean tensile strength, mean tensile modulus and mean yield strength of each material. With this, the results is that PP is the most elastic among them, but the strongest material seems to be GPPS as it has the highest mean tensile strength and mean tensile modulus among the four different plastics. But GPPS did not yield at all as it does not have any crosslinks to favour elastic properties. Content Page
* Results & calculations
Tensile strength is the maximum strength that a material can withstand before breaking. This experiment, tensile strength testing, calculates and finds the tensile strength of four plastic materials with the LLOYD testing machine.
In order to do so, we find the tensile strength, tensile modulus, and the yield strength of each material type. Tensile modulus – the material’s tendency to be deformed elastically when a force is applied to it. Yield strength – the stress at which the material deforms permanently when a force is applied to it. After the results are obtained, we will be able to find out which material type is the hardest, which is the most ductile. Theory
Theory behind the calculations:
The reason why three samples from each plastic material type are used is because by using only one result would be very inaccurate. Since the values of tensile strength, tensile modulus and yield strength are not absolute; we may not get the same value of tensile strength, tensile modulus or yield strength...