Computerized latex and polyurethane foams compression testing machine

1.introductions

Computerized latex and polyurethane foams compression set testing machine is used to measure and determine compression set of latex and polyurethane foams. The compression set means the difference between the initial thickness and the final thickness of a test piece of cellular material, latex and polyurethane foams, after compression for a given time at a given temperature after a given recovery time. The test software of computerized electronic compression testing machine allow user to set certain deformation, speed and force during loading, and can display test time ,test force, displacement in real time. Test curves of force vs time, force vs deformation, displacement vs time, etc. can be displayed as well. Test results can be saved and printed after test.

2. 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

3. relative test method for compression set test of flexible cellular polymeric material

GB/T 6669 / ISO 1856 flexible cellular polymeric material --- determination of compression set

4. specification of testing machine

china computerized latex and polyurethane foams compression testing machine universal testing machine UTM tensile test machine material testing mechanical testing equipment tensile strength testing price supplier factory manufacturer vendor

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.