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Summary:
Summary:
The goal of this project was to build and test structural members of trusses. We utilized a lever and a bucket to compare the different compression and tensile strength that each member can endure.
Lesson Plan:
Lesson Plan:
Lesson #2-Test the Strength of Structural Members.pdfProcess:
Process:
This lever-based testing machine applies controlled tension or compression forces to a member with reasonable accuracy. The loading arm pivots on a bolt, and the T-Line and C-Line mark where specimens are attached. A bucket is placed in the Notch and weight is slowly added to test the tensile or compressive strength of a specific member. For the Compression test the member is placed under the C-Line and for the Tension test the member is attached to the T-Line
Data Table: Tension Table Test
Data Table: Tension Table Test
Graph: Tensile Strength vs. Member Width
Graph: Tensile Strength vs. Member Width
Example of Tension Test Member
Example of Tension Test Member
Q1: The load-deformation curve is a positive linear line, proving that the material does not show elastic behavior because after consistency adding weight it immediately snaps and demonstrates little to no plastic deformation beforehand.
Q2: The Mat board is a brittle material because of it's property to snap or crack and break under pressure instead of bending or deforming plastically.
Data Table: Compression Test Table
Data Table: Compression Test Table
Example of Compression Test Members
Example of Compression Test Members
Graph: Compression Strength vs. Length
Graph: Compression Strength vs. Length
Q1: The longer the length of the member, the lower the compressive strength because longer members are more likely to buckle under load, reducing the material’s ability to hold compressive force.
Example of Buckling Failure in a Longer Compression Test Member:
Example of Buckling Failure in a Longer Compression Test Member:
IMG_1030.MOVConclusion:
Conclusion:
The testing showed that tensile and compressive strengths increase with member width and decrease with length. Tensile forces in the trusses increased according to member width ratio, while compression tests show that longer specimens were more likley to buckle. The material behaves very brittle-like because of the way that the material breaks under tensile forces.
Source of Error:
Source of Error:
Different Mat Boards: Using mat boards with different thickness or quality affected how the specimens acted, causing inconsistent load distribution. This changed could lead to some members failing earlier than others, reducing how reliable these results are.
2. Faulty Stability: If the setup was not stable, the member could shift or move during testing. This instability could introduce uneven forces, causing premature bending, buckling, or inaccurate measurements.
3. Poor Clamping: Wrongly clamped specimens may have slipped or moved under the load, stopping uniform stress to act across the member. This could result in lower measured strengths and increased change in strength between tests.
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