Mechanical Testing Standards
3 min

Exploring the Types of Mechanical Testing and its Methods

Posted by: TÜV SÜD Expert Date: 19 Jul 2023

Mechanical testing helps you understand these properties and determine the lifecycle of the material to ensure the safety of the individuals working with them. You can employ different types of mechanical testing to understand the various mechanical properties of the material. Each test uses unique testing methods, and you must determine which method best suits your requirements.

Some of the most frequent mechanical testing methods include:

  • Chemical analysis
  • Fatigue testing
  • Fracture mechanics
  • Hardness testing
  • Stress rupture and creep testing
  • Tensile testing

Apart from these most popular mechanical testing methods, a host of standardised tests determine the different mechanical properties of the material. These tests are generally independent of the geometry or machining of the raw material. However, as specimen size can impact certain properties, such as tensile strength, mechanical testing is usually performed on finished parts.

Types of Mechanical Testing

Depending on the mechanical property under investigation, you can classify the most common mechanical tests into the following eight types:

  1. Hardness Testing
    Hardness testing allows you to determine the “hardness” or resistance to penetration of mechanical structures post-production, especially the ones requiring heat treatment. Some common standardised tests for hardness testing include Vickers Hardness Test, Barcol Testing, Knoop Hardness Test, and Shore Durometer Test.
  2. Tensile Testing
    Tensile testing determines the strength of the material under tension, making sure the material meets minimum requirements for strength and ductility. This involves stretching the material to its breaking point. In addition to tensile strength, tensile testing also provides a stress-strain curve, yield stress, tensile stress, Young’s Modulus, and percentage elongation to failure of the material.
  3. Impact Testing
    Impact testing determines the force a mechanical part can endure before it breaks. This usually involves a pendulum to control the force, and some of the most common tests for impact testing include ASTM standardised tests like Izod Testing and Charpy Testing.
  4. Fracture Toughness Testing
    Fracture toughness testing allows you to determine the energy the material (or part) would need to cause failure. This also gives you insights into the material’s ability to withstand a flaw and how long the part can perform before encountering a critical failure. You can use these insights to plan maintenance and repair schedules for various mechanical parts. The most common tests for fracture toughness are Linear-elastic, K–R Curve, and Elastic-Plastic tests.[1][3]
  5. Creep Testing
    Creep testing allows you to determine the effects of long-term stress on the material or parts under question at high temperatures relative to the boiling point. The test involves applying constant stress at a constant temperature to the specimen to record the strain versus time graph.
  6. Fatigue Testing
    Fatigue testing allows you to determine the fatigue strength of the material under question, offering insights into the number of load cycles the material can go through before experiencing failure and allowing you to schedule maintenance. You can compare the fatigue strength curve of the material to your design criteria to ensure the material and part are fit to serve your purpose. However, it is advisable to fatigue test the finished part instead of the raw material, as its geometry often alters its mechanical properties. Some popular standardised tests for fatigue testing include Fatigue Crack Growth Testing, Strain-controlled Smooth Specimen Testing, and Load-controlled Smooth Specimen Testing.
  7. Corrosion Resistance
    Corrosion resistance testing gives insights into rust, chemical damage, and the usual wear and tear resistance of the material under test. Generally, you can determine the corrosion resistance by exposing small samples of the materials to a particular environment over a relatively short period and evaluating the severity and type of corrosion. This way, you can select the material most suited for your needs and maximise the part’s lifespan.[1][5]
  8. Non-destructive Testing
    Non-destructive testing allows you to evaluate the mechanical properties of the material damaging the material or the part. Some examples of non-destructive testing methods include Acoustic Emission Testing, Electromagnetic Testing, Ground Penetrating Radar, and Laser Testing. The different techniques in non-destructive testing make them versatile and useful across many industries, as they cause no damage to the material or part under investigation.

Conclusion

Mechanical testing of the materials and parts you are using lets you understand their mechanical properties and helps you plan design upgrades, maintenance, and repairs while ensuring the safety of the people working with them. However, you must ensure that you use the mechanical testing methods best suited to your needs and testing parameters.

TÜV SÜD offers a wide range of mechanical testing methods, standards, and equipment and can help you understand and better maintain your equipment. With decades of experience and interdisciplinary expertise, we can deliver mechanical safety testing services globally with quick turnaround times. You can be sure of the quality of your testing services as businesses, as regulatory authorities around the globe, accept the TÜV SÜD certification mark.

For more details, contact us today.

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