The behavior of materials under mechanical loads is called mechanical properties. These properties are generally based on interatomic bond forces. However, the internal structure of the material is also effective in this. Therefore, by changing the internal structure of the materials, different mechanical properties can be obtained in the same material. These mechanical properties of metals are examined by different test methods under different loading and operating conditions. For example, the force per unit area in a material to which a force is applied is called tension. If the applied force is perpendicular, the length of the material increases or shortens. This is normal stress. However, if the applied force is in the material, this causes an angle change and this is called shear stress. However, the forces applied to a material can create both normal and shear stress in the material.

Strength or endurance is a science that studies the behavior of objects against various external factors and internal forces caused by them. Strength science, which is a sub-branch of mechanical science, is also defined as the mechanics of deformable bodies.

Essentially, all machines must be capable of withstanding the loads to which they are subjected, under the prescribed installation and operating conditions and in the required configurations, if the effects of the weather and the forces exerted by humans are normal. This condition must be met not only during the use of the machines, but also during transport, installation, and, where necessary, disassembly.

For this reason, machines and lifting devices must be designed and manufactured to prevent malfunctions from fatigue and wear, taking into account the functions expected of them. For this purpose, when selecting the materials used during design and production, factors such as corrosion, impact, wear, extreme temperature, fatigue, aging and brittleness should be taken into consideration according to the targeted working environment conditions.

Machines and lifting equipment must be manufactured to withstand overload and should not cause permanent deformations or structural defects under overload. These are particularly checked during mechanical strength tests. During these tests, when the strength calculations are made, the static test coefficient value is used to ensure an adequate safety level. In general, this coefficient value is:

• 1,5 for manual machines and lifting equipment
• 1,25 for other machines

Therefore, the machines must undergo dynamic tests with the maximum working load calculated with these coefficients and should not cause any malfunction.

The Regulation on Health and Safety in the Use of Work Equipment issued by the Ministry of Labor and Social Security in 2013 is also intended to ensure occupational safety. Businesses use many machines, equipment and components depending on their field of activity. In order to ensure that they can be used safely, mechanical strength tests should be performed regularly.

These tests must be carried out by mechanical engineers, machine technicians or high technicians. Mechanical strength tests are mainly carried out by non-destructive testing methods and the testers must be trained according to the TS EN ISO 9712 Non-destructive testing (NDT) personnel qualification and certification - General specifications standard (previous TS EN 473 standard).

Mechanical strength tests are not limited to machines and components, of course. In this context, the main mechanical strength tests are: tensile tests, compression tests, bending tests, impact tests, shear tests, fracture toughness tests, splitting tests, ultrasound tests, fracture energy determination, poisson ratio determination, hardness measurement tests.

Mechanical strength tests are applied in many building materials such as concrete, glass, steel, stone, brick, tile, wood and composite panels.

All mechanical tests comply with local and foreign standards as well as the legal regulations in force.