Specific strength
Material Tensile strength ( MPa ) Density ( g / cm³ ) Specific strength ( kN · m / kg ) Breaking length ( km )
Concrete 2-5 2.30 5.22 0.44
Rubber 15 0.92 16.3 1.66
Copper 220 8.92 24.7 2.51
Polypropylene / PP 25-40 0.90 28-44 2.8-4.5
( Poly ) acrylonitrile-butadiene-styrene / ABS 41-45 1.05 39-43
Polyethylene terephthalate / Polyester / PET 80 1.3-1.4 57-62
Piano wire / ASTM 228 Steel 1590-3340 7.8 204-428
Polylactic acid / Polylactide / PLA 53 1.24 43
Low Carbon Steel ( AISI 1010 ) 365 7.87 46.4 4.73
Stainless steel ( 304 ) 505 8.00 63.1 6.4
Brass 580 8.55 67.8 6.91
Nylon 78 1.13 69.0 7.04
Titanium 344 4.51 76 7.75
CrMo Steel ( 4130 ) 560-670 7.85 71-85 7.27-8.70
Aluminium alloy ( 6061-T6 ) 310 2.70 115 11.70
Oak 90 0.78-0.69 115-130 12-13
Inconel ( X-750 ) 1250 8.28 151 15.4
Magnesium alloy 275 1.74 158 16.1
Aluminium alloy ( 7075-T6 ) 572 2.81 204 20.8
Pine Wood ( American eastern white ) 78 .35 223 22.7
Examples
The specific strength is a material's strength (force per unit area at failure) divided by its density. It is also known as the strength-to-weight ratio or strength/weight ratio or strength-to-mass ratio. In fiber or textile applications, tenacity is the usual measure of specific strength. The SI unit for specific strength is Pa m/kg, or N·m/kg, which is dimensionally equivalent to m/s, though the latter form is rarely used. Specific strength has the same units as specific energy, and is related to the maximum specific energy of rotation that an object can have without flying apart due to centrifugal force. Another way to describe specific strength is breaking length, also known as self support length: the maximum length of a vertical column of the material (assuming a fixed cross-section) that could suspend its own weight when supported only at the top. For this measurement, the definition of weight is the force of gravity at the Earth's surface (standard gravity, 9.80665 m/s) applying to the entire length of the material, not diminishing with height. This usage is more common with certain specialty fiber or textile applications. The materials with the highest specific strengths are typically fibers such as carbon fiber, glass fiber and various polymers, and these are frequently used to make composite materials (e.g. carbon fiber-epoxy). These materials and others such as titanium, aluminium, magnesium and high strength steel alloys are widely used in aerospace and other applications where weight savings are worth the higher material cost. Note that strength and stiffness are distinct.