Kiran Sangha
The Brinell Hardness Test and Brinell scale are one of many tests that can be used to characterize hardness of materials. The Brinell Hardness Test uses tests materials by penetrating the material using an indenter. Typically, a test uses a 0.39 in diameter steel ball as the indenter with a 6,614 lbf of force. The amount of force applied changes between softer and harder materials. So, the force applied on the iron nail would be much larger than the force applied on the plastic chair. For much harder materials, a tungsten carbide ball is used instead of a steel ball. The hardness is calculated as BHN (Brinell Hardness Number). This value is calculated using the formula shown in the image above. The BHN value measures the hardness of a material. If one wanted to test the tensile strength (the strength of a material against breaking under tension), the BHN can be converted into ultimate tensile strength (UTS). The relationship between these two values is based on Meyer's index from Meyer's law. According to, if Meter's index is less than 2.2 then the ratio of UTS to BHN is 0.36. If it is greater, then the ratio increases. This ratio essentially determines the relationship of a material's tensile strength and hardness. Here is a list of some common materials and their Brinell hardness numbers (BHN): pure aluminum: 15 HB mild steel: 120 HB glass: 1550 HB Information source: Image source:
Mahesh Godavarti
Can you add more context to your question? Please provide some examples of objects, and why you are interested in measuring the durability of such objects.
vsc satya
examples of an object are Iron nail and a plastic chair. I am interested in measuring the durability of such objects because I see many objects breaking easliy where as some do not so I want to know if we can measure durability of an object.
Vivekanand Vellanki
Durability is measured differently for different objects. Durability of a car is measured in the average number of km travelled before the car is unusable. Durability of packaged food is measured as the time after which the food is unsafe for consumption. Packaged food explicit "expiry date" for this. In general, durability of an object is the number of days after which an object becomes unusable (an iron nail rusts; or a plastic chair breaks). Durability depends on how the object is used; the environment conditions, etc.