Tester and Single Factor ANOVA Lab

Tester and Single Factor ANOVA Lab

Topics Covered:

Tester Fundamentals

One-way ANOVA

Equipment Required:

Instron Tester (LBG 707)

LabVIEW version 8.0 or higher

Calipers or Micrometer

Each team member (max. 5) should supply one brand of material.

E.g. Cloth, Paper, Rubber, or Plastic Strings

Objective: Perform a one-way ANOVA to test whether a factor has an effect on the experimental outcome. Your factor is the brand of material supplied by each team member. (In an experimental situation, the brand will have some different characteristic to mark it different from the other materials). Briefly, describe your material and try to note any different properties. Perform a pull test on each level of material (try to keep the same dimensions) to failurefive times. Record the force (response data) required to break each sample. 1

ISE370 Industrial Automation

Instron is a manufacturer of test equipment designed to evaluate the mechanical properties of materials and components.Instron tension testers, or pull testers, are used to determine the tensile strength of various materials from metals to plastics. These tensile testing systems utilize various technologies to apply a range of tensile forces. Standard tensile forces can be applied with an electromechanical tensile tester while higher tension loads require a static hydraulic tensile system.Typically, the testing involves taking a small sample with a fixed cross-section area, and then pulling it with a controlled, gradually increasing force until the sample changes shape or breaks.

Electromechanical Systems

Electromechanical or universal testing machines are most commonly used for static testing in a tensile or compression mode within a single frame. They are also referred to as pull testers. Additional test types include tensile, compression, shear, flexure, peel, tear, cyclic, and bend tests. Capacities for these systems range from low-load forces of 0.5 kN (112 lbf) up to high-capacity 600 kN (135,000 lbf) test frames.

Tensile strengths are rarely used in the design of ductilemembers, but they are important in brittle members. They are tabulated for common materials such as alloys, ceramics, plastics, and wood. Tensile strength is defined as a stress, which is measured as force per unit area. For some non-homogeneous materials, it can be reported just as a force or as a force per unit width. The customary unitispounds-force per square inch (lbf/in² or psi), or kilo-pounds per square inch (ksi), which is equal to 1000 psi; kilo-pounds per square inch are commonly used for convenience when measuring tensile strengths.

Ductile materials

Stress vs. Strain curve typical of aluminum
1. Ultimate strength
2. Yield strength
3. Proportional limit stress
4. Fracture
5. Offset strain (typically 0.2%)

Brittle materials, such as concreteand carbon fiber, are characterized by failure at small strains. They often fail while still behaving in a linear elastic manner, and thus do not have a defined yield point. Testing of several identical specimens will result in different failure stresses, this is due to the Weibull modulus of the brittle material. 1

ISE370 Industrial Automation

1. Test the null hypothesis that there is no difference in the force required to rupture your samples of material by different levelsusing significanceα = 0.05.

2. Build a LabVIEW program (vi) that will perform a one-way analysis of variance. Clearly have your program state the outcome of your decision to accept or reject the null hypothesis. (Hint: There is a 1D-ANOVA.vi on the Functions Palette under Mathematics > Prob & Stat > ANOVA. It is listed in the NI_AALPro.lvlib). Tester Procedure:

1)Login select LNG 707 – (Instron This Computer)

2)Power-up Instron tester after boot-up. (RHCorner-back of tester).

3)Load “Merlin” Software (Red Icon on left side screen). Many OKs….

4)Select the Balance Icon in the Upper RH-Corner. (Middle Icon of 3).Select:Balance (on screen)>Done. (Balance is Auto).

5)Select: Test Area Icon URHC >Set to “Below Crosshead”

6)Use the File Menu to select the method: Open Method > Select: ASTM D1117-98.mtA

7)Parameters to check: 1-Sample Specimen >Continue> Speed = 1.00 then...

8)Start Test Icon (Upper Right Hand Corner of screen).

9)Install a sample when requested. Record the force when completed. Stretch is slow. The tester will automatically reset so press “Continue”.

Design Notes: Stress = ForceTear/Area(Normalize for different sizes).

Cross-sectional area = Thickness x Width. If you utilize a“constant”cross-sectional area, use the rupture force (newtons) for response data. No need to normalize the data. Samples should utilize a dog-bone design so rupture/tear should be in the center of the sample not near the clamps. Sept 21 Pass: rpodr10 This computer, Instron 1