elastic modulus
Let an agent explain elastic moduli and their kinds, relay definitions, relations and typical values from mechanics and materials sources, describe the Lame parameters, and distinguish elastic moduli from strength, stiffness of a structure, hardness and the plastic regime.
Research draft, second pass
A second pass drafted this model: the structure a model of this thing needs, and what is known about it in the world. The line under this one says how the second half was obtained - researched against sources, or recalled without web access, in which case nothing here was read anywhere and every claim is a lead to verify. Unreviewed either way.
written by Claude from model knowledge without web access - no source was read, every claim is a lead to verify
Researched by: Claude
Purpose and description
Let an agent explain elastic moduli and their kinds, relay definitions, relations and typical values from mechanics and materials sources, describe the Lame parameters, and distinguish elastic moduli from strength, stiffness of a structure, hardness and the plastic regime.
A quantity measuring the resistance of a material to elastic deformation, defined as the ratio of stress to strain in the elastic region, in several forms depending on the mode of deformation, including Young s modulus for tension, the shear modulus for shear, the bulk modulus for uniform compression, and the Lame parameters, the first and second of which express the same elastic properties of isotropic materials in the equations of elasticity; the moduli are related to each other and to Poisson s ratio.
What it is for: Characterising elastic response of materials.
It can be explain the moduli; relay relations and values; describe the Lame parameters; distinguish related properties.
Distinguishing features
Elastic regime
Several moduli
Two independent for isotropic materials
Units of pressure
What it looks like
Not a visible object; a material constant.
Physical character
Young s modulus, steel: about 200 GPa
shear modulus, steel: about 80 GPa
bulk modulus, water: about 2.2 GPa
independent constants, isotropic: 2 count
How it is recognised
Ratio of stress to strain in elastic deformation
Young s modulus, shear modulus, bulk modulus, Lame first and second parameters
Strength is the stress at failure; structural stiffness depends on geometry; hardness resists indentation; plastic behaviour is beyond the elastic limit
Related models
is a kind of - in registry terms
is a kind of - in registry terms
is related to - by elasticity relations
is defined by - in the linear regime
In practice
Families and kinds
Young s modulus
shear modulus
bulk modulus
Lame parameters
P-wave modulus
anisotropic elastic constants
Standards and regulation
ASTM and ISO test standards for elastic moduli
SI units in pascals
Failure modes and hazards
Confusing modulus with strength or stiffness
Applying isotropic relations to anisotropic materials
Registry aliases mixing moduli and Lame parameters
Also called
Where this came from
wikidata · CC0 1.0
Drafted structure
Bundle to layer to finding to question, as the second pass will find it: 4 bundles · 8 layers · 8 findings · 16 questions.
Understand What an elastic modulus is.
Science.
Definition
Definition.
Definition
Definition.
- What is an elastic modulus, and how does it differ from strength, structural stiffness, hardness and plastic behaviour? definition
- Is the question about a specific modulus, relations, measurement or a material value? boundary
Kinds
Kinds.
Kinds
Kinds.
- What are Young s, shear and bulk moduli and the Lame parameters? definition
- Which entry fits the specific modulus? action
Theory Theory.
Science.
Relations
Relations.
Relations
Relations.
- How are the moduli and Poisson s ratio related for isotropic materials? provenance
- Which references are standard? provenance
Anisotropy
Anisotropy.
Anisotropy
Anisotropy.
- How are elastic constants described for anisotropic materials such as crystals and composites? provenance
- Which sources are cited? provenance
Practice Measurement and use.
Application.
Measurement
Measurement.
Measurement
Measurement.
- How are moduli measured by tensile tests, ultrasound and nanoindentation? provenance
- Which entry fits tensile testing? action
Design
Design.
Design
Design.
- How are moduli used in structural design and material selection? provenance
- Which entry fits material selection? action
Context Values and history.
Context.
Values
Typical values.
Values
Values.
- What are typical moduli of metals, polymers, ceramics and biological tissues? provenance
- Which entry fits the specific material? action
History
History.
History
History.
- How did Hooke, Young, Lame and others develop elasticity theory? provenance
- Which entry fits the history of elasticity? action
What the second pass must settle
- Should shear modulus and bulk modulus be separate primary entries?
- How should mechanics sources be linked?
- The registry entry has merged aliases naming specific moduli and parameters; should they be split off?