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Implementation of Hermite–Ritz method and Navier’s technique for vibration of functionally graded porous nanobeam embedded in Winkler–Pasternak elastic foundation using bi-Helmholtz nonlocal elasticity
Journal of Mechanics of Materials and Structures ( IF 0.9 ) Pub Date : 2020-07-12 , DOI: 10.2140/jomms.2020.15.405
Subrat Kumar Jena , Snehashish Chakraverty , Mohammad Malikan , Hamid Sedighi

The vibration characteristics of functionally graded porous nanobeam embedded in an elastic substrate of Winkler–Pasternak type are investigated. Classical beam theory or Euler–Bernoulli beam theory has been incorporated to address the displacement of the FG nanobeam. bi-Helmholtz type of nonlocal elasticity is being used to capture the small scale effect of the FG nanobeam. Further, the nanobeam is assumed to have porosity, distributed evenly along the thickness throughout the cross-section. Young’s modulus and mass density of the nanobeam are considered to vary along the thickness from ceramic to metal constituents in accordance with power-law exponent model. A numerically efficient method, namely the Hermite–Ritz method, is incorporated to compute the natural frequencies of hinged-hinged, clamped-hinged, and clamped-clamped boundary conditions. A closed-form solution is also obtained for hinged-hinged (HH) boundary condition by employing Navier’s technique. The advantages of using Hermite polynomials as shape functions are orthogonality, a large domain that makes the method more computationally efficient and avoids ill-conditioning for higher values of polynomials. Additionally, the present results are validated with other existing results in special cases demonstrating excellent agreement. A comprehensive study has been carried out to justify the effectiveness or convergence of the present model or method. Likewise, impacts of various scaling parameters such as Helmholtz and bi-Helmholtz types of nonlocal elasticity, porosity volume fraction index, power-law exponent, and elastic foundation on frequency parameters have been investigated.



中文翻译:

利用双Helmholtz非局部弹性来实现嵌入Winkler-Pasternak弹性地基中的功能梯度多孔纳米梁振动的Hermite-Ritz方法和Navier技术的实现

研究了嵌入Winkler–Pasternak型弹性基底中的功能梯度多孔纳米束的振动特性。经典射束理论或欧拉-伯努利射束理论已被纳入解决FG纳米束的位移问题。bi-Helmholtz类型的非局部弹性正被用来捕获FG纳米束的小规模效应。此外,假定纳米束具有孔隙率,其沿着整个横截面的厚度均匀分布。根据幂律指数模型,认为纳米束的杨氏模量和质量密度沿着厚度从陶瓷到金属成分变化。结合了一种数值有效的方法,即Hermite-Ritz方法,以计算铰接,夹固和夹固边界条件的固有频率。还通过使用Navier技术获得了铰链-铰接(HH)边界条件的封闭形式解。使用Hermite多项式作为形状函数的优势是正交性,这是一个大域,这使该方法的计算效率更高,并且避免了因多项式值较高而产生的不良情况。另外,在证明极好的一致性的特殊情况下,本结果与其他现有结果进行了验证。已经进行了全面的研究以证明本模型或方法的有效性或收敛性。同样,还研究了各种缩放参数,例如亥姆霍兹和双亥姆霍兹类型的非局部弹性,孔隙体积分数指数,幂律指数和弹性基础对频率参数的影响。一个较大的域,使该方法的计算效率更高,并且避免了多项式更高值的不良情况。此外,在证明极好的一致性的特殊情况下,本结果与其他现有结果进行了验证。已经进行了全面的研究以证明本模型或方法的有效性或收敛性。同样,还研究了各种缩放参数,例如亥姆霍兹和双亥姆霍兹类型的非局部弹性,孔隙体积分数指数,幂律指数和弹性基础对频率参数的影响。一个较大的域,使该方法的计算效率更高,并且避免了多项式更高值的不良情况。此外,在证明极好的一致性的特殊情况下,本结果与其他现有结果进行了验证。已经进行了全面的研究以证明本模型或方法的有效性或收敛性。同样,还研究了各种比例缩放参数,例如亥姆霍兹和双亥姆霍兹类型的非局部弹性,孔隙体积分数指数,幂律指数和弹性基础对频率参数的影响。在特殊情况下,本结果已与其他现有结果进行了验证,这表明了极好的一致性。已经进行了全面的研究以证明本模型或方法的有效性或收敛性。同样,还研究了各种缩放参数,例如亥姆霍兹和双亥姆霍兹类型的非局部弹性,孔隙体积分数指数,幂律指数和弹性基础对频率参数的影响。在特殊情况下,本结果已与其他现有结果进行了验证,这表明了极好的一致性。已经进行了全面的研究以证明本模型或方法的有效性或收敛性。同样,还研究了各种缩放参数,例如亥姆霍兹和双亥姆霍兹类型的非局部弹性,孔隙体积分数指数,幂律指数和弹性基础对频率参数的影响。

更新日期:2020-08-20
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