Definitions /Dictionary/Glossary - nptel
Definitions /Dictionary/Glossary - nptel
Definitions /Dictionary/Glossary - nptel
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Nonwoven Roving: Reinforcement composed of continuous rovings loosely gathered together.<br />
Normal Distribution: A two parameter (μ, σ) family of probability distributions for which the<br />
probability that an observation will fall between ‘a’ and ‘b’ is given by the area under the curve<br />
between ‘a’ and ‘b’.<br />
2<br />
1 ⎡ (x − μ)<br />
⎤<br />
f(x) = exp⎢−<br />
2 ⎥<br />
σ 2π ⎢⎣ 2σ<br />
⎥⎦<br />
Normalization: A mathematical procedure for adjusting raw test values for fiber-dominated<br />
properties to a single (specified) fiber volume content.<br />
Normalized Stress: Stress value adjusted to specified fiber volume content by multiplying the<br />
measured stress value by the ratio of specimen fiber volume to the specified fiber volume. This<br />
ratio may be obtained directly by experimentally measuring fiber volume, or indirectly by<br />
calculation using specimen thickness and fiber aerial weight.<br />
NOT: Non-destructive testing. It is broadly considered synonymous with NOI.<br />
Notch Sensitivity: The extent to which the sensitivity of a material to fracture is increased by the<br />
presence of a surface non-homogeneity such as a notch, a sudden change in section, a crack or a<br />
scratch. Low notch sensitivity is usually associated with ductile materials and high notch<br />
sensitivity with brittle materials.<br />
NPG Gel Coat: Neopentyl glycol gel coat has enhanced weatherability compared to non-NPG<br />
gel coat.<br />
Nylon: The generic name for all synthetic polyamides.<br />
Nylon Plastic: Plastics based on a resin composed principally of a long chain synthetic<br />
polymeric amide that has recurring amide groups as an integral part of the main polymer chain.<br />
Observed Significance Level (OSL): The probability of observing a more extreme<br />
value of the test-statistic when the null hypothesis is true.<br />
Off-axis Laminate: A laminate whose principal axis is oriented at an angle (8) other than 00 or<br />
900 with respect to a reference direction, usually related to principal load or stress direction.<br />
Offset Shear Strength: (from valid execution of a material property shear response test) the<br />
value of shear stress at the intersection between a line parallel to the shear chord modulus of<br />
elasticity and the shear stress/strain curve, where the line has been offset along the shear strain<br />
axis from the origin by a specified strain offset value.<br />
Oligomer: A polymer consisting of only a few monomer units such as a dimer, trimer, etc., or<br />
their mixtures.