Computerized wood compression modulus of elasticity testing machine

1. Introductions

The computerized wood grain-to-grain compressive elastic modulus testing machine is equipped with compression test attachment and clamp-type extensometer to measure the wood-grain compressive elastic modulus, that is, when the wood is compressed along the grain, within the proportional limit , the compressive elastic modulus of the wood along the grain is obtained by the ratio of stress to strain. The test of the elastic modulus of wood along the grain adopts a cuboid sample with a sample size of 60x20x20mm. During the test, the test is loaded to the lower limit load at a constant rate, and the deformation value is recorded. Then continue to load at the same loading speed to the upper limit load, record the deformation value, and unload immediately. Repeat the test steps 6 times.

2. relative test method

GB/T 15777 method of determination of the modulus of elasticity in compression parallel to grain of wood

3. Relative manufacturing and calibrating test method for testing machine

GB/T2611 general requirements for testing machines

GB/T16491 electronic universal testing machine

GB/T16825.1 verification of static uniaxial testing machines --- part 1: tension / compression testing machines --- verification and calibration of the force measuring system

ISO7500-1 metallic materials--- verification of static uniaxial testing machine --- part 1: tension / compression testing machines --- verification and calibration of the force measuring system

ASTM E4 standard practice for force verification of testing machines

EN 10002-2 tensile testing of metallic materials --- part 2: verification of the force measuring system of the tensile testing machine

4. working conditions of testing machine

4.1 The room temperature is 10-35℃.

4.2 Relative humidity≤80%.

4.3 There is no vibration around, no corrosive medium, and no strong magnetic field interference.

4.4 The power supply voltage fluctuation should not exceed 10% of the rated voltage.

4.5 Install it horizontally on a solid foundation with a level of 0.2/1000.

5. features of test software

5.1. Automatic stop: After the sample is broken, the moving beam stops automatically;

5.2. Condition storage: The test control data and sample conditions can be made into modules, which facilitates the batch test;

5.3. Automatic speed change: The speed of the moving beam during the test can be changed automatically according to the preset program or manually;

5.4. Automatic calibration: the system can automatically realize the calibration of the indication accuracy;

5.5. Automatic save: After the test is over, the test data and curves are automatically saved;

5.6. Process realization: the test process, measurement, display and analysis are all completed by the microcomputer;

5.7. Batch test: for samples with the same parameters, it can be completed in sequence after one setting

5.8. Test software: WINDOWS interface, menu prompt, mouse operation;

5.9. Display mode: data and curves are dynamically displayed with the test process;

5.10. Curve traversal: After the test is completed, the curve can be re-analyzed, and the test data corresponding to any point on the curve can be found with the mouse;

5.11. Curve selection: Stress-strain, force-displacement, force-time, displacement-time and other curves can be selected for display and printing as required;

12. Test report: The report can be prepared and printed according to the format required by the user;

5.13. Limit protection: with two levels of program control and mechanical limit protection;

5.14. Overload protection: when the load exceeds 3-5% of the maximum value of each gear, it will automatically stop;

5.15. The test results are obtained in two modes, automatic and manual, and reports are automatically formed, which makes the data analysis process simple.

6. specification of testing machine

metal tensile testing, steel tensile testing, aluminum tensile testing, metal elongation test, yield strength test for metals, ductility testing, metal sample preparation for tensile tests, ASTM metal tensile test, ISO metal tensile testing standards

How to Select the Right Tensile, Compression, Bending, Shear, Peel, and Tear Testing Machine: Calculation Formulas with Examples

Selecting the appropriate testing machine for tensile, compression, bending, shear, peel, and tear tests requires careful consideration of multiple factors, including the force range, specimen dimensions, test standards, and machine capabilities. Below are the key calculation formulas to help determine the necessary machine specifications, along with examples for better understanding.

1. Tensile Testing Machine Selection

Tensile testing machines measure the maximum tensile strength and elongation of materials.

Key Formula:

F_max=σ_max × A

Where:

F_max = Maximum required force (N)

σ_max = Ultimate tensile strength of the material (MPa)

A = Cross-sectional area of the specimen (mm²)

Example: For a steel specimen with σ_max =400MPa and cross-sectional area A =100mm²:

F_max=400 × 100=40,000N (40kN)

A 50 kN tensile testing machine would be suitable.

2. Compression Testing Machine Selection

Compression tests determine a material's resistance to compressive forces.

Key Formula:

F_max=σ_c × A

Where:

F_max = Maximum required force (N)

σ_c = Compressive strength of the material (MPa)

A = Cross-sectional area of the specimen (mm²)

Example: For a concrete cube with σ_c =30MPa and A =150²=22,500mm²:

F_max=30 × 22,500=675,000N (675kN)

A 1000 kN compression testing machine would be ideal.

3. Bending Testing Machine Selection

Bending tests evaluate the flexural strength of materials.

Key Formula for Three-Point Bending:

Where:

σ_f = Flexural stress (MPa)

F= Applied force (N)

L= Span length (mm)

b= Width of the specimen (mm)

h= Thickness of the specimen (mm)

Example: For a wooden beam with L=500mm, b=50mm, h=25mm, and requiring a stress of 10 MPa:

A 5 kN bending tester would be suitable.

4. Shear Testing Machine Selection

Shear tests determine the shear strength of materials.

Key Formula:

F_max=τ × A

Where:

F_max = Maximum shear force (N)

τ= Shear strength of the material (MPa)

A = Shear area (mm²)

Example: For an aluminum sheet with τ=90 MPa and A=200mm²:

F_max=90×200=18,000N(18kN)

A 20 kN shear testing machine is recommended.

5. Peel Testing Machine Selection

Peel tests measure the adhesion strength between bonded materials.

Key Formula:

Where:

P= Peel strength (N/mm)

F= Measured force (N)

W= Width of the specimen (mm)

Example: For a tape with F=50N and W=25mm:

A peel testing machine with at least 5 N force capacity is required.

6. Tear Testing Machine Selection

Tear tests determine the resistance of a material to tearing forces.

Key Formula:

Where:

F_tear= Tear strength (N/mm)

F= Measured force (N)

t= Thickness of the specimen (mm)

Example: For a rubber sheet with F=100N and t=2mm:

A tear testing machine with 100 N capacity is needed.

When selecting a testing machine, ensure that the maximum force capacity of the machine is at least 1.2 to 1.5 times the calculated force to account for safety margins and unexpected variations. Additionally, consider compliance with relevant test standards (ASTM, ISO, GB, EN, JIS) and machine features such as speed control, data acquisition, and test automation.

By using the above formulas and examples, engineers and manufacturers can accurately determine the appropriate testing machine specifications for their specific material and application requirements.