大筷子93
屈服强度 代号：σs；单位：MPa(或N/mm2) 指金属材料受拉力作用到某一程度时，其变形突然增加很大时的材料抵抗外力的能力 .读西格玛 Sigma 以下供你参考希腊字母的正确读法1 Α α alpha a:lf 阿尔法 2 Β β beta bet 贝塔 3 Γ γ gamma ga:m 伽马 4 Δ δ delta delt 德尔塔 5 Ε ε epsilon ep`silon 伊普西龙 6 Ζ ζ zeta zat 截塔 7 Η η eta eit 艾塔 8 Θ θ thet θit 西塔 9 Ι ι iot aiot 约塔 10 Κ κ kappa kap 卡帕 11 ∧ λ lambda lambd 兰布达 12 Μ μ mu mju 缪 13 Ν ν nu nju 纽 磁阻系数 14 Ξ ξ xi ksi 克西 15 Ο ο omicron omik`ron 奥密克戎 16 ∏ π pi pai 派 17 Ρ ρ rho rou 肉 18 ∑ σ sigma `sigma 西格马 19 Τ τ tau tau 套 20 Υ υ upsilon jup`silon 宇普西龙 21 Φ φ phi fai 佛爱 22 Χ χ chi phai 西 23 Ψ ψ psi psai 普西 角速； 24 Ω ω omega o`miga 欧米伽 希腊字母读法 Αα：阿尔法 Alpha Ββ：贝塔 Beta Γγ：伽玛 Gamma Δδ：德尔塔 Delte Εε：艾普西龙 Epsilon ζ ：捷塔 Zeta Ζη：依塔 Eta Θθ：西塔 Theta Ιι：艾欧塔 Iota Κκ：喀帕 Kappa ∧λ：拉姆达 Lambda Μμ：缪 Mu Νν：拗 Nu Ξξ：克西 Xi Οο：欧麦克轮 Omicron ∏π：派 Pi Ρρ：柔 Rho ∑σ：西格玛 Sigma Ττ：套 Tau Υυ：宇普西龙 Upsilon Φφ：fai Phi Χχ：器 Chi Ψψ：普赛 Psi Ωω：欧米伽 Omega
MyronKiven
抗拉强度：Ultimate tensile strength (UTS), often shortened to tensile strength (TS) or ultimate strength,[1][2] is the maximum stress that a material can withstand while being stretched or pulled before failing or breaking. Tensile strength is distinct fromcompressive strength.https://en.wikipedia.org/wiki/Ultimate_tensile_strength屈服强度：yield strengthA yield strength or yield point of a material is defined in engineering and materials scienceas the stress at which a material begins to deform plastically. Prior to the yield point the material will deform elastically and will return to its original shape when the applied stress is removed. Once the yield point is passed, some fraction of the deformation will be permanent and non-reversible. In the three-dimensional space of the principal stresses (), an infinite number of yield points form together ayield surface.https://en.wikipedia.org/wiki/Yield_(engineering)延伸率：ductility is a solid material's ability to deform undertensilestress; this is often characterized by the material's ability to be stretched into a wire.https://en.wikipedia.org/wiki/Ductility断面收缩率：The percentage decrease in the cross- sectional area of a tensile test piece caused by wasting or necking of the specimen. It is expressed as a percentage of the original area of the test piece and is a measure of ductility. 在维基百科里面，比例极限，弹性极限，屈服强度，都指向屈服强度（yield strength)
长平公主
抗拉强度 compressive strengthCompressive strength is the capacity of a material or structure to withstand loads tending to reduce size.屈服强度 yield strengthA yield strength of a material is defined in engineering and materials science as the stress at which a material begins to deform plastically.比例极限 proportionality limit Up to this amount of stress, stress is proportional to strain (Hooke's law), so the stress-strain graph is a straight line, and the gradient will be equal to the elastic modulus of the material.弹性极限 elastic limit Beyond the elastic limit, permanent deformation will occur. The elastic limit is therefore the lowest stress at which permanent deformation can be measured. 延伸率 stretch ratioThe stretch ratio or extension ratio is a measure of the extensional or normal strain of a differential line element, which can be defined at either the undeformed configuration or the deformed configuration. 断面收缩率 shrinkage ratioWhen the material tensioning fracture section decreased, the ratio of cross-sectional area reduced to the original area of the section is called shrinkage ratio.
蜜糖Rose
δs。
屈服强度的定义就是：大于此极限的外力作用，将会使零件永久失效，没法恢复，这个压强叫做屈服强度。
屈服强度，英文Yield Strength，又称为屈服极限，常用符号δs，是材料屈服的临界应力值。
其实意思就是一个钢筋承受能承受的最大的外力，如低碳钢的屈服极限为207MPa，当大于此极限的外力作用之下，零件将会产生永久变形，无法恢复。小于这个的，零件还会恢复原来的样子。
屈服强度测定
无明显屈服现象的金属材料需测量其规定非比例延伸强度或规定残余伸长应力，而有明显屈服现象的金属材料，则可以测量其屈服强度、上屈服强度、下屈服强度。一般而言，只测定下屈服强度。
通常测定上屈服强度及下屈服强度的方法有两种：图示法和指针法。
一、图示法
试验时用自动记录装置绘制力－夹头位移图。要求力轴比例为每mm所代表的应力一般小于10N/mm，曲线至少要绘制到屈服阶段结束点。在曲线上确定屈服平台恒定的力Fe、屈服阶段中力首次下降前的最大力Feh或者不到初始瞬时效应的最小力FeL。
二、指针法
试验时，当测力度盘的指针首次停止转动的恒定力或者指针首次回转前的最大力或者不到初始瞬时效应的最小力，分别对应着屈服强度、上屈服强度、下屈服强度。
三、屈服强度、上屈服强度、下屈服强度可以按以下公式来计算：
1、屈服强度计算公式：Re=Fe/So；Fe为屈服时的恒定力。
2、上屈服强度计算公式：Reh=Feh/So；Feh为屈服阶段中力首次下降前的最大力。
3、下屈服强度计算公式：ReL=FeL/So；FeL为不到初始瞬时效应的最小力FeL。
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