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- In mechanics, the flexural modulus or bending modulus is an intensive property that is computed as the ratio of stress to strain in flexural deformation, or the tendency for a material to resist bending. It is determined from the slope of a stress-strain curve produced by a flexural test (such as the ASTM D790), and uses units of force per area. The flexural modulus defined using the 2-point (cantilever) and 3-point bend tests assumes a linear stress strain response. For a 3-point test of a rectangular beam behaving as an isotropic linear material, where w and h are the width and height of the beam, I is the second moment of area of the beam's cross-section, L is the distance between the two outer supports, and d is the deflection due to the load F applied at the middle of the beam, the flexural modulus: From elastic beam theory and for rectangular beam thus (Elastic modulus) For very small strains in isotropic materials like glass, metal or polymer, flexural or bending modulus of elasticity is equivalent to the tensile modulus (Young's modulus) or compressive modulus of elasticity. However, in anisotropic materials, for example wood, these values may not be equivalent. Moreover, composite materials like fiber-reinforced polymers or biological tissues are inhomogeneous combinations of two or more materials, each with different material properties, therefore their tensile, compressive, and flexural moduli usually are not equivalent. (en)
- 弯曲模量（flexural modulus）為一力學名詞．是指在一材料弯曲變形，或是可能會彎曲的情形下應力和應變的比值。弯曲模量可以用弯曲測試（ASTM D 790）下應力應變曲線的斜率，其單位是面積面積下的力，弯曲模量是內含性質。 右圖是一個長方形樑的三點測試，寬度為w，高度為h，L是外側兩個支持點之間的距離，d是因為在中間受力F而產生的形變，其弯曲模量為： 針對線性的樑理論針對長方形的樑， 因此（弹性模量） 理想上弯曲模量會等於彈力變化下的拉力或是壓力弹性模量，不過實際上，兩者仍有差異，在塑膠材料中最為明顯。 (zh)
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