Specific modulus
Encyclopedia
Specific modulus is a materials property consisting of the elastic modulus
Elastic modulus
An elastic modulus, or modulus of elasticity, is the mathematical description of an object or substance's tendency to be deformed elastically when a force is applied to it...

 per mass density
Density
The mass density or density of a material is defined as its mass per unit volume. The symbol most often used for density is ρ . In some cases , density is also defined as its weight per unit volume; although, this quantity is more properly called specific weight...

 of a material. It is also known as the stiffness to weight ratio or specific stiffness. High specific modulus materials find wide application in aerospace
Aerospace
Aerospace comprises the atmosphere of Earth and surrounding space. Typically the term is used to refer to the industry that researches, designs, manufactures, operates, and maintains vehicles moving through air and space...

 applications where minimum structural weight
Weight
In science and engineering, the weight of an object is the force on the object due to gravity. Its magnitude , often denoted by an italic letter W, is the product of the mass m of the object and the magnitude of the local gravitational acceleration g; thus:...

 is required. The dimensional analysis
Dimensional analysis
In physics and all science, dimensional analysis is a tool to find or check relations among physical quantities by using their dimensions. The dimension of a physical quantity is the combination of the basic physical dimensions which describe it; for example, speed has the dimension length per...

 yields units of distance squared per time squared.

The utility of specific modulus is to find materials which will produce structures with minimum weight, when the primary design limitation is deflection or physical deformation, rather than load at breaking—this is also known as a "stiffness-driven" structure. Many common structures are stiffness-driven over much of their use, such as airplane wings, bridges, masts, and bicycle frames.

To emphasize the point, consider the issue of choosing a material for building an airplane. Aluminum seems obvious because it is "lighter" than steel, but steel is stronger than aluminum, so one could imagine using thinner steel components to save weight without sacrificing (tensile) strength. The problem with this idea is that there would be a significant sacrifice of stiffness, allowing, e.g., wings to flex unacceptably. Because it is stiffness, not tensile strength, that drives this kind of decision for airplanes, we say that they are stiffness-driven.

The connection details of such structures may be more sensitive to strength (rather than stiffness) issues due to effects of stress risers.
Specific modulus is not to be confused with specific strength
Specific strength
The specific strength is a material's strength divided by its density. It is also known as the strength-to-weight ratio or strength/weight ratio. In fiber or textile applications, tenacity is the usual measure of specific strength...

, a term that compares strength to density.

Specific stiffness in tension

The use of specific stiffness in tension
Tension
Tension may refer to:* The Void , also known as Tension in some regions* Tension , a factor that affects knitting gauge...

 applications is straightforward. Both stiffness
Stiffness
Stiffness is the resistance of an elastic body to deformation by an applied force along a given degree of freedom when a set of loading points and boundary conditions are prescribed on the elastic body.-Calculations:...

 in tension
Tension
Tension may refer to:* The Void , also known as Tension in some regions* Tension , a factor that affects knitting gauge...

 and total mass
Mass
Mass can be defined as a quantitive measure of the resistance an object has to change in its velocity.In physics, mass commonly refers to any of the following three properties of matter, which have been shown experimentally to be equivalent:...

 for a given length are directly proportional to cross-sectional area
Cross section (geometry)
In geometry, a cross-section is the intersection of a figure in 2-dimensional space with a line, or of a body in 3-dimensional space with a plane, etc...

. Thus performance of a beam in tension will depend on Young's modulus
Young's modulus
Young's modulus is a measure of the stiffness of an elastic material and is a quantity used to characterize materials. It is defined as the ratio of the uniaxial stress over the uniaxial strain in the range of stress in which Hooke's Law holds. In solid mechanics, the slope of the stress-strain...

 divided by density
Density
The mass density or density of a material is defined as its mass per unit volume. The symbol most often used for density is ρ . In some cases , density is also defined as its weight per unit volume; although, this quantity is more properly called specific weight...

.

Specific stiffness in buckling and bending

Specific stiffness can be used in the design of beams
Beam (structure)
A beam is a horizontal structural element that is capable of withstanding load primarily by resisting bending. The bending force induced into the material of the beam as a result of the external loads, own weight, span and external reactions to these loads is called a bending moment.- Overview...

 subject to bending
Bending
In engineering mechanics, bending characterizes the behavior of a slender structural element subjected to an external load applied perpendicularly to a longitudinal axis of the element. The structural element is assumed to be such that at least one of its dimensions is a small fraction, typically...

 or Euler buckling
Buckling
In science, buckling is a mathematical instability, leading to a failure mode.Theoretically, buckling is caused by a bifurcation in the solution to the equations of static equilibrium...

, since bending and buckling are stiffness-driven. However, the role that density
Density
The mass density or density of a material is defined as its mass per unit volume. The symbol most often used for density is ρ . In some cases , density is also defined as its weight per unit volume; although, this quantity is more properly called specific weight...

 plays changes depending on the problem's constraints.

Beam with fixed dimensions; goal is weight reduction

Examining the formulas for buckling
Buckling
In science, buckling is a mathematical instability, leading to a failure mode.Theoretically, buckling is caused by a bifurcation in the solution to the equations of static equilibrium...

 and deflection
Deflection (engineering)
In engineering, deflection is the degree to which a structural element is displaced under a load. It may refer to an angle or a distance.The deflection distance of a member under a load is directly related to the slope of the deflected shape of the member under that load and can be calculated by...

, we see that the force required to achieve a given deflection or to achieve buckling depends directly on Young's modulus
Young's modulus
Young's modulus is a measure of the stiffness of an elastic material and is a quantity used to characterize materials. It is defined as the ratio of the uniaxial stress over the uniaxial strain in the range of stress in which Hooke's Law holds. In solid mechanics, the slope of the stress-strain...

.

Examining the density
Density
The mass density or density of a material is defined as its mass per unit volume. The symbol most often used for density is ρ . In some cases , density is also defined as its weight per unit volume; although, this quantity is more properly called specific weight...

 formula, we see that the mass
Mass
Mass can be defined as a quantitive measure of the resistance an object has to change in its velocity.In physics, mass commonly refers to any of the following three properties of matter, which have been shown experimentally to be equivalent:...

 of a beam depends directly on the density.

Thus if a beam's cross-sectional dimensions are constrained and weight reduction is the primary goal, performance of the beam will depend on Young's modulus
Young's modulus
Young's modulus is a measure of the stiffness of an elastic material and is a quantity used to characterize materials. It is defined as the ratio of the uniaxial stress over the uniaxial strain in the range of stress in which Hooke's Law holds. In solid mechanics, the slope of the stress-strain...

 divided by density
Density
The mass density or density of a material is defined as its mass per unit volume. The symbol most often used for density is ρ . In some cases , density is also defined as its weight per unit volume; although, this quantity is more properly called specific weight...

.

Beam with fixed weight; goal is increased stiffness

By contrast, if a beam's weight is fixed, its cross-sectional dimensions are unconstrained, and increased stiffness is the primary goal, the performance of the beam will depend on Young's modulus divided by either density squared or cubed. This is because a beam's overall stiffness
Stiffness
Stiffness is the resistance of an elastic body to deformation by an applied force along a given degree of freedom when a set of loading points and boundary conditions are prescribed on the elastic body.-Calculations:...

, and thus its resistance to Euler buckling
Buckling
In science, buckling is a mathematical instability, leading to a failure mode.Theoretically, buckling is caused by a bifurcation in the solution to the equations of static equilibrium...

 when subjected to an axial load and to deflection
Deflection (engineering)
In engineering, deflection is the degree to which a structural element is displaced under a load. It may refer to an angle or a distance.The deflection distance of a member under a load is directly related to the slope of the deflected shape of the member under that load and can be calculated by...

 when subjected to a bending moment
Bending Moment
A bending moment exists in a structural element when a moment is applied to the element so that the element bends. Moments and torques are measured as a force multiplied by a distance so they have as unit newton-metres , or pound-foot or foot-pound...

, is directly proportional to both the Young's modulus of the beam's material and the second moment of area
Second moment of area
The second moment of area, also known as the area moment of inertia, moment of inertia of plane area, or second moment of inertia is a property of a cross section that can be used to predict the resistance of beams to bending and deflection, around an axis that lies in the cross-sectional plane...

 (area moment of inertia) of the beam.

Comparing the list of area moments of inertia with formulas for area
Area
Area is a quantity that expresses the extent of a two-dimensional surface or shape in the plane. Area can be understood as the amount of material with a given thickness that would be necessary to fashion a model of the shape, or the amount of paint necessary to cover the surface with a single coat...

 gives the appropriate relationship for beams of various configurations.
Beam's cross-sectional area increases in two dimensions

Consider a beam whose cross-sectional area increases in two dimensions, e.g. a solid round beam or a solid square beam.

By combining the area
Area
Area is a quantity that expresses the extent of a two-dimensional surface or shape in the plane. Area can be understood as the amount of material with a given thickness that would be necessary to fashion a model of the shape, or the amount of paint necessary to cover the surface with a single coat...

 and density
Density
The mass density or density of a material is defined as its mass per unit volume. The symbol most often used for density is ρ . In some cases , density is also defined as its weight per unit volume; although, this quantity is more properly called specific weight...

 formulas, we can see that the radius of this beam will vary with approximately the inverse of the square of the density for a given mass.

By examining the formulas for area moment of inertia, we can see that the stiffness of this beam will vary approximately as the fourth power of the radius.

Thus the second moment of area will vary approximately as the inverse of the density squared, and performance of the beam will depend on Young's modulus
Young's modulus
Young's modulus is a measure of the stiffness of an elastic material and is a quantity used to characterize materials. It is defined as the ratio of the uniaxial stress over the uniaxial strain in the range of stress in which Hooke's Law holds. In solid mechanics, the slope of the stress-strain...

 divided by density
Density
The mass density or density of a material is defined as its mass per unit volume. The symbol most often used for density is ρ . In some cases , density is also defined as its weight per unit volume; although, this quantity is more properly called specific weight...

 squared
.
Beam's cross-sectional area increases in one dimension

Consider a beam whose cross-sectional area increases in one dimension, e.g. a thin-walled round beam or a rectangular beam whose height but not width is varied.

By combining the area
Area
Area is a quantity that expresses the extent of a two-dimensional surface or shape in the plane. Area can be understood as the amount of material with a given thickness that would be necessary to fashion a model of the shape, or the amount of paint necessary to cover the surface with a single coat...

 and density
Density
The mass density or density of a material is defined as its mass per unit volume. The symbol most often used for density is ρ . In some cases , density is also defined as its weight per unit volume; although, this quantity is more properly called specific weight...

 formulas, we can see that the radius or height of this beam will vary with approximately the inverse of the density for a given mass.

By examining the formulas for area moment of inertia, we can see that the stiffness of this beam will vary approximately as the third power of the radius or height.

Thus the second moment of area will vary approximately as the inverse of the cube of the density, and performance of the beam will depend on Young's modulus
Young's modulus
Young's modulus is a measure of the stiffness of an elastic material and is a quantity used to characterize materials. It is defined as the ratio of the uniaxial stress over the uniaxial strain in the range of stress in which Hooke's Law holds. In solid mechanics, the slope of the stress-strain...

 divided by density
Density
The mass density or density of a material is defined as its mass per unit volume. The symbol most often used for density is ρ . In some cases , density is also defined as its weight per unit volume; although, this quantity is more properly called specific weight...

 cubed
.

However, caution must be exercised in using this metric. Thin-walled beams are ultimately limited by local buckling and lateral-torsional buckling. These buckling modes depend on material properties other than stiffness and density, so the stiffness-over-density-cubed metric is at best a starting point for analysis. For example, most wood species score better than most metals on this metric, but many metals can be formed into useful beams with much thinner walls than could be achieved with wood, given wood's greater vulnerability to local buckling. The performance of thin-walled beams can also be greatly modified by relatively minor variations in geometry such as flange
Flange
A flange is an external or internal ridge, or rim , for strength, as the flange of an iron beam such as an I-beam or a T-beam; or for attachment to another object, as the flange on the end of a pipe, steam cylinder, etc., or on the lens mount of a camera; or for a flange of a rail car or tram wheel...

s and stiffeners.

Stiffness versus strength in bending

Note that the ultimate strength of a beam in bending depends on the ultimate strength of its material and its section modulus
Section modulus
Section modulus is a geometric property for a given cross-section often used in the design of beams or flexural members. There are two types of section moduli, the elastic section modulus and the plastic section modulus .- Notation :...

, not its stiffness and second moment of area. Its deflection, however, and thus its resistance to Euler buckling, will depend on these two latter values.

Approximate specific stiffness for various materials

Approximate specific stiffness for various materials. No attempt is made to correct for materials whose stiffness varies with their density.
Material Young's modulus
Young's modulus
Young's modulus is a measure of the stiffness of an elastic material and is a quantity used to characterize materials. It is defined as the ratio of the uniaxial stress over the uniaxial strain in the range of stress in which Hooke's Law holds. In solid mechanics, the slope of the stress-strain...

 in GPa
Pascal (unit)
The pascal is the SI derived unit of pressure, internal pressure, stress, Young's modulus and tensile strength, named after the French mathematician, physicist, inventor, writer, and philosopher Blaise Pascal. It is a measure of force per unit area, defined as one newton per square metre...

Density
Density
The mass density or density of a material is defined as its mass per unit volume. The symbol most often used for density is ρ . In some cases , density is also defined as its weight per unit volume; although, this quantity is more properly called specific weight...

 in g/cm3
Young's modulus over density in 106 m2s−2 Young's modulus over density squared in 103 m5kg−1s−2 Young's modulus over density cubed in m8kg−2s−2
Rubber
Rubber
Natural rubber, also called India rubber or caoutchouc, is an elastomer that was originally derived from latex, a milky colloid produced by some plants. The plants would be ‘tapped’, that is, an incision made into the bark of the tree and the sticky, milk colored latex sap collected and refined...

 (small strain)
±0.045 ±0.145 ±0.051 ±0.05655 ±0.0621
Low density polyethylene
Low density polyethylene
Low-density polyethylene is a thermoplastic made from petroleum. It was the first grade of polyethylene, produced in 1933 by Imperial Chemical Industries using a high pressure process via free radical polymerization. Its manufacture employs the same method today. LDPE is commonly recycled and has...

±0.015 ±0.005 ±0.005 ±0.015
PTFE (Teflon)
HDPE
Polypropylene
Polypropylene
Polypropylene , also known as polypropene, is a thermoplastic polymer used in a wide variety of applications including packaging, textiles , stationery, plastic parts and reusable containers of various types, laboratory equipment, loudspeakers, automotive components, and polymer banknotes...

 
±0.3 ±0.33 ±0.37 ±0.41
Polyethylene terephthalate
Polyethylene terephthalate
Polyethylene terephthalate , commonly abbreviated PET, PETE, or the obsolete PETP or PET-P, is a thermoplastic polymer resin of the polyester family and is used in synthetic fibers; beverage, food and other liquid containers; thermoforming applications; and engineering resins often in combination...

±0.35 ±0.0425 ±0.3 ±0.23 ±0.225
Nylon
Nylon
Nylon is a generic designation for a family of synthetic polymers known generically as polyamides, first produced on February 28, 1935, by Wallace Carothers at DuPont's research facility at the DuPont Experimental Station...

±1.0 ±0.9 ±0.75 ±0.65
Polystyrene
Polystyrene
Polystyrene ) also known as Thermocole, abbreviated following ISO Standard PS, is an aromatic polymer made from the monomer styrene, a liquid hydrocarbon that is manufactured from petroleum by the chemical industry...

±0.25 ±0.2 ±0.25 ±0.2
Biaxially-oriented Polypropylene
Polypropylene
Polypropylene , also known as polypropene, is a thermoplastic polymer used in a wide variety of applications including packaging, textiles , stationery, plastic parts and reusable containers of various types, laboratory equipment, loudspeakers, automotive components, and polymer banknotes...

±1.0 ±1.11 ±1.23 ±1.37
Medium-density fibreboard
Medium-density fibreboard
Medium-density fiberboard is an engineered wood product formed by breaking down hardwood or softwood residuals into wood fibres, often in a defibrator, combining it with wax and a resin binder, and forming panels by applying high temperature and pressure...

4
Copper
Copper
Copper is a chemical element with the symbol Cu and atomic number 29. It is a ductile metal with very high thermal and electrical conductivity. Pure copper is soft and malleable; an exposed surface has a reddish-orange tarnish...

 (Cu)
117 13
Brass
Brass
Brass is an alloy of copper and zinc; the proportions of zinc and copper can be varied to create a range of brasses with varying properties.In comparison, bronze is principally an alloy of copper and tin...

 and bronze
Bronze
Bronze is a metal alloy consisting primarily of copper, usually with tin as the main additive. It is hard and brittle, and it was particularly significant in antiquity, so much so that the Bronze Age was named after the metal...

±12.5 ±0.165 ±2.0 ±0.25 ±0.03
Oak wood
Wood
Wood is a hard, fibrous tissue found in many trees. It has been used for hundreds of thousands of years for both fuel and as a construction material. It is an organic material, a natural composite of cellulose fibers embedded in a matrix of lignin which resists compression...

 (along grain)
11 ±0.17 ±3.5 ±9.5 ±20.0
Concrete
Properties of concrete
Concrete has relatively high compressive strength, but significantly lower tensile strength, and as such is usually reinforced with materials that are strong in tension . The elasticity of concrete is relatively constant at low stress levels but starts decreasing at higher stress levels as matrix...

 (under compression)
40±10 17±4 ±1.75 ±0.7
Average lightweight Balsa 21 190 1,700
"Unreal Stiff" lightweight Balsa 21 260 3,200
Tungsten
Tungsten
Tungsten , also known as wolfram , is a chemical element with the chemical symbol W and atomic number 74.A hard, rare metal under standard conditions when uncombined, tungsten is found naturally on Earth only in chemical compounds. It was identified as a new element in 1781, and first isolated as...

 (W)
400 21
Osmium
Osmium
Osmium is a chemical element with the symbol Os and atomic number 76. Osmium is a hard, brittle, blue-gray or blue-blacktransition metal in the platinum family, and is the densest natural element. Osmium is twice as dense as lead. The density of osmium is , slightly greater than that of iridium,...

 (Os)
550 24
Wrought iron
Wrought iron
thumb|The [[Eiffel tower]] is constructed from [[puddle iron]], a form of wrought ironWrought iron is an iron alloy with a very low carbon...

200±10 ±0.2 26±2 ±0.35 ±0.055
Glass-reinforced plastic
Glass-reinforced plastic
Fiberglass , is a fiber reinforced polymer made of a plastic matrix reinforced by fine fibers of glass. It is also known as GFK ....

±14.45 18±8 ±4.35 ±2.5
Pine wood
Wood
Wood is a hard, fibrous tissue found in many trees. It has been used for hundreds of thousands of years for both fuel and as a construction material. It is an organic material, a natural composite of cellulose fibers embedded in a matrix of lignin which resists compression...

±0.155 20±6 47±26 120±89
Sitka spruce green ±0.7 ±2 64±5 172±13
Steel
Steel
Steel is an alloy that consists mostly of iron and has a carbon content between 0.2% and 2.1% by weight, depending on the grade. Carbon is the most common alloying material for iron, but various other alloying elements are used, such as manganese, chromium, vanadium, and tungsten...

200 ±0.15 25±0.5 ±0.1 ±0.02
Magnesium
Magnesium
Magnesium is a chemical element with the symbol Mg, atomic number 12, and common oxidation number +2. It is an alkaline earth metal and the eighth most abundant element in the Earth's crust and ninth in the known universe as a whole...

 metal
Metal
A metal , is an element, compound, or alloy that is a good conductor of both electricity and heat. Metals are usually malleable and shiny, that is they reflect most of incident light...

 (Mg)
45 26 15
Aluminium
Aluminium
Aluminium or aluminum is a silvery white member of the boron group of chemical elements. It has the symbol Al, and its atomic number is 13. It is not soluble in water under normal circumstances....

69 26
Titanium alloy
Titanium alloy
Titanium alloys are metallic materials which contain a mixture of titanium and other chemical elements. Such alloys have very high tensile strength and toughness , light weight, extraordinary corrosion resistance, and ability to withstand extreme temperatures...

s
±7.5 25±2 ±0.35 ±0.08
Sitka spruce dry ±0.8 26±2 65±5 162±12
Tooth enamel
Tooth enamel
Tooth enamel, along with dentin, cementum, and dental pulp is one of the four major tissues that make up the tooth in vertebrates. It is the hardest and most highly mineralized substance in the human body. Tooth enamel is also found in the dermal denticles of sharks...

 (largely calcium phosphate
Calcium phosphate
Calcium phosphate is the name given to a family of minerals containing calcium ions together with orthophosphates , metaphosphates or pyrophosphates and occasionally hydrogen or hydroxide ions ....

)
83 30 11
E-Glass fiber 81 31 12
Molybdenum
Molybdenum
Molybdenum , is a Group 6 chemical element with the symbol Mo and atomic number 42. The name is from Neo-Latin Molybdaenum, from Ancient Greek , meaning lead, itself proposed as a loanword from Anatolian Luvian and Lydian languages, since its ores were confused with lead ores...

 (Mo)
329 32
Basalt fiber
Basalt fiber
Basalt fiber or fibre is a material made from extremely fine fibers of basalt, which is composed of the minerals plagioclase, pyroxene, and olivine. It is similar to carbon fiber and fiberglass, having better physicomechanical properties than fiberglass, but being significantly cheaper than...

89 33 12
S-Glass fiber 89 36 14
Glass
Glass
Glass is an amorphous solid material. Glasses are typically brittle and optically transparent.The most familiar type of glass, used for centuries in windows and drinking vessels, is soda-lime glass, composed of about 75% silica plus Na2O, CaO, and several minor additives...

70±20 ±0.2 28±10 ±4.8 ±2.1
single-crystal Yttrium iron garnet
Yttrium iron garnet
Yttrium iron garnet is a kind of synthetic garnet, with chemical composition 323, or Y3Fe5O12. It is a ferrimagnetic material with a Curie temperature of 550 K....

 (YIG)
200 39
Tungsten carbide
Tungsten carbide
Tungsten carbide is an inorganic chemical compound containing equal parts of tungsten and carbon atoms. Colloquially, tungsten carbide is often simply called carbide. In its most basic form, it is a fine gray powder, but it can be pressed and formed into shapes for use in industrial machinery,...

 (WC)
550±100 ±6.5 ±0.4 ±0.025
Flax
Flax
Flax is a member of the genus Linum in the family Linaceae. It is native to the region extending from the eastern Mediterranean to India and was probably first domesticated in the Fertile Crescent...

 fiber
45±34 ±0.15 ±29.35 30±25 25±21
Jute
Jute
Jute is a long, soft, shiny vegetable fibre that can be spun into coarse, strong threads. It is produced from plants in the genus Corchorus, which has been classified in the family Tiliaceae, or more recently in Malvaceae....

 fiber (tension)
Kevlar
Kevlar
Kevlar is the registered trademark for a para-aramid synthetic fiber, related to other aramids such as Nomex and Technora. Developed at DuPont in 1965, this high strength material was first commercially used in the early 1970s as a replacement for steel in racing tires...

 29 (tensile only)
49 34 24
Dyneema SK25 Ultra-high-molecular-weight polyethylene (tensile only) 52 54 55 57
Kevlar
Kevlar
Kevlar is the registered trademark for a para-aramid synthetic fiber, related to other aramids such as Nomex and Technora. Developed at DuPont in 1965, this high strength material was first commercially used in the early 1970s as a replacement for steel in racing tires...

 49 (tensile only)
78 54 38
Silicon
Silicon
Silicon is a chemical element with the symbol Si and atomic number 14. A tetravalent metalloid, it is less reactive than its chemical analog carbon, the nonmetal directly above it in the periodic table, but more reactive than germanium, the metalloid directly below it in the table...

185 79 34 15
Alumina fiber (Al2O3) 300 ±0.315 84±7 24±4 ±1.74
Carbon fiber reinforced plastic (70/30 fibre/matrix, unidirectional, along grain) 181 113 71 44
Dyneema SK78/Honeywell Spectra 2000 Ultra-high-molecular-weight polyethylene (tensile only) 121±11 125±11 128±12 132±12
Silicon carbide
Silicon carbide
Silicon carbide , also known as carborundum, is a compound of silicon and carbon with chemical formula SiC. It occurs in nature as the extremely rare mineral moissanite. Silicon carbide powder has been mass-produced since 1893 for use as an abrasive...

 (SiC)
450 140 44 14
Beryllium
Beryllium
Beryllium is the chemical element with the symbol Be and atomic number 4. It is a divalent element which occurs naturally only in combination with other elements in minerals. Notable gemstones which contain beryllium include beryl and chrysoberyl...

 (Be)
287 155 84 45
Boron fiber 400 157 62 24
Diamond
Diamond
In mineralogy, diamond is an allotrope of carbon, where the carbon atoms are arranged in a variation of the face-centered cubic crystal structure called a diamond lattice. Diamond is less stable than graphite, but the conversion rate from diamond to graphite is negligible at ambient conditions...

 (C)
1,220 346 98 28
Dupont E130 carbon fiber 896 417 194 90

Approximate specific stiffness for various species of wood
Species Young's modulus
Young's modulus
Young's modulus is a measure of the stiffness of an elastic material and is a quantity used to characterize materials. It is defined as the ratio of the uniaxial stress over the uniaxial strain in the range of stress in which Hooke's Law holds. In solid mechanics, the slope of the stress-strain...

 in GPa
Pascal (unit)
The pascal is the SI derived unit of pressure, internal pressure, stress, Young's modulus and tensile strength, named after the French mathematician, physicist, inventor, writer, and philosopher Blaise Pascal. It is a measure of force per unit area, defined as one newton per square metre...

Density
Density
The mass density or density of a material is defined as its mass per unit volume. The symbol most often used for density is ρ . In some cases , density is also defined as its weight per unit volume; although, this quantity is more properly called specific weight...

in g/cm3
Young's modulus over density in 106 m2s−2 Young's modulus over density squared in 103 m5kg−1s−2 Young's modulus over density cubed in m8kg−2s−2
Applewood or wild apple (Pyrus malus )
Ash, black (Fraxinus nigra )
Ash, blue (quadrangulata )
Ash, green (Fraxinus pennsylvanica lanceolata )
Ash, white (Fraxinus americana )
Aspen (Populus tremuloides )
Aspen, large tooth (PopuIus grandidentata )
Basswood (Tilia glabra or Tilia americanus )
Beech (Fagus grandifolia or Fagus americana )
Beech, blue (Carpinus caroliniana )
Birch, gray (Betula populifolia )
Birch, paper (Betula papyrifera )
Birch, sweet (Betula lenta )
Buckeye, yellow (Aesculus octandra )
Butternut (Juglans cinerea )
Cedar, eastern red (Juniperus virginiana )
Cedar, northern white (Thuja occidentalis )
Cedar, southern white (Chamaecyparis thvoides )
Cedar, western red (Thuja plicata )
Cherry, black (Prunus serotina )
Cherry, wild red (Prunus pennsylvanica )
Chestnut (Castanea dentata )
Cottonwood, eastern (Populus deltoides )
Cypress, southern (Taxodium distichum )
Dogwood (flowering) (Cornus florida )
Douglas fir (coast type) (Pseudotsuga taxifolia )
Douglas fir (mountain type) (Pseudotsuga taxifolia )
Ebony, Andaman marble-wood (India) (Diospyros kursii )
Ebony, Ebè marbre (Maritius, E. Africa) (Diospyros melanida )
Elm, American (Ulmus americana )
Elm, rock (Ulmus racemosa or Ulmus thomasi )
Elm, slippery (Ulmus fulva or pubescens )
Eucalyptus, Karri (W. Australia) (Eucalyptus diversicolor )
Eucalyptus, Mahogany (New South Wales)(Eucalyptus hemilampra)
Eucalyptus, West Australian mahogany (Eucalyptus marginata )
Fir, balsam (Abies balsamea)
Fir, silver (Abies amabilis )
Gum, black (Nyssa sylvatica )
Gum, blue (Eucalyptus globulus )
Gum, red (Liquidambar styraciflua )
Gum, tupelo (Nyssa aquatica )
Hemlock eastern (Tsuga canadensis )
Hemlock, mountain (Tsuga martensiana )
Hemlock, western (Tsuga heterophylla )
Hickory, bigleaf shagbark (Hicoria laciniosa )
Hickory, mockernut (Hicoria alba )
Hickory, pignut (Hicoria glabra )
Hickory, shagbark (Hicoria ovata )
Hornbeam (Ostrya virginiana )
Ironwood, black (Rhamnidium ferreum ) ±1.64 ±2.78 ±3.56
Larch, western (Larix occidentalis )
Locust, black or yellow (Robinia pseudacacia )
Locust honey (Gleditsia triacanthos )
Magnolia, cucumber (Magnolia acuminata )
Mahogany (W. Africa) (Khaya ivorensis )
Mahogany (E. India) (Swietenia macrophylla )
Mahogany (E. India) (Swietenia mahogani )
Maple, black (Acer nigrum )
Maple, red (Acer rubrum )
Maple, silver (Acer saccharinum )
Maple, sugar (Acer saccharum )
Oak, black (Quercus velutina )
Oak, bur (Quercus macrocarpa )
Oak, canyon live (Quercus chrysolepis )
Oak, laurel (Quercus montana )
Oak, live (Quercus virginiana )
Oak, post (Quercus stellata or Quercus minor )
Oak, red (Quercus borealis )
Oak, swamp chestnut (Quercus montana (Quercus prinus) )
Oak swamp white (Quercus bicolor or Quercus platanoides )
Oak, white (Quercus alba )
Persimmon (Diospyros virginiana )
Pine, eastern white (Pinus strobus )
Pine, jack (Pinus banksiana or Pinus divericata )
Pine, loblolly (Pinus taeda )
Pine, longleaf (Pinus palustris )
Pine, pitch (Pinus rigida )
Pine, red (Pinus resinosa )
Pine, shortleaf (Pinus echinata )
Poplar, balsam (Populus balsamifera or Populus candicans )
Poplar, yellow (Liriodendron tulipifera )
Redwood (Sequoia sempervirens )
Sassafras (Sassafras uariafolium )
Satinwood (Ceylon) (Chloroxylon swietenia )
Sourwood (Oxydendrum arboreum )
Spruce, black (Picea mariana )
Spruce, red (Picea rubra or Picea rubens )
Spruce, white (Picea glauca )
Sycamore (Platanus occidentalis )
Tamarack (Larix laricina or Larix americana )
Teak (India) (Tectona grandis )
Walnut, black (Juglans nigra )
Willow, black (Salix nigra )
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