The normal contact stiffness model between bearing hole and shaft journal in radial sliding bearing was built through combining the fractal theory and the joint interface virtual material.Through revising the condition of Weierstrass function's nondifferentiability at any point,it was proved rigorously that the limited range of fractal dimension is 1 ≤D ＜ 2.Numerical simulation showed that the side face contact coefficient in bearing contact is equal to or less than 1;the side face contact coefficient of inner contact is larger than that of outer contact;when the shaft journal radius and normal contact load increase and joint interface virtual material thickness decreases,the side face contact coefficient in bearing contact increases;the real contact area of inner contact is bigger than that of outer contact;when the shaft journal radius increases and fractal roughness,plane Brinell hardness of bearing hole and joint interface virtual material thickness decrease,the actual contact area increases;when the fractal dimension increases from 1.4 to 1.5,the real contact area increases;when the fractal dimension increases from 1.5 to 1.9,the real contact area decreases;Hertz stress decreases with increase in shaft journal radius;Hertz stress of inner contact is less than that of outer contact;the normal contact stiffness of bearing inner contact is larger than that of outer contact;when the normal contact load,fractal dimension and shaft journal radius increase and fractal roughness,elastic modulus of shaft journal,bearing length and joint interface virtual material thickness decrease,the normal contact stiffness increases.%将分形理论与结合部虚拟材料相结合,构建径向滑动轴承中轴承孔与轴颈的法向接触刚度模型.修正Weierstrass函数在任一点处处不可求导的条件.严格论证分形维数的限定范围是1≤D＜2.数值模拟表明:轴承接触的侧面接触系数≤1.内接触的侧面接触系数＞外接触的侧面接触系数.随着轴颈半径、法向接触载荷的增加,结合部虚拟材料厚度的减小,轴承接触的侧面接触系数增加.内接触的真实接触面积大于外接触的真实接触面积.随着轴颈半径的增加,分形粗糙度、轴承孔平面布氏硬度、结合部虚拟材料厚度的减少,真实接触面积提高.对于固定的法向接触载荷,当分形维数由1.4增大至1.5时,真实接触面积随之增加;当分形维数由1.5增大至1.9时,真实接触面积随之减少.赫兹应力随着轴颈半径的增加而下降.内接触的赫兹应力小于外接触的赫兹应力.轴承内接触的法向接触刚度大于外接触的法向接触刚度.另外,随着法向接触载荷、分形维数、轴颈半径的增加,分形粗糙度、轴颈弹性模量、轴承长度、结合部虚拟材料厚度的减小,法向接触刚度增加.
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