Analytical solution

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1 - روش تحلیلی جدید مبتنی بر معادله ریکاتی برای یافتن جواب‌های سالیتونی معادله غیرخطی لاکشمینن-پوسیزین- دانیل
احمد نیرمه

در این مقاله روش تحلیلی مبتنی بر معادله ریکاتی از نوع ------------------، جهت تبدیل معادله غیر خطی لاکشمینن-پوسیزین-دانیل به یک معادله معمولی غیرخطی و به‌دست آوردن جواب‌های سالیتونی آن، مورد مطالعه قرار گرفته شده است. جواب های به‌دست آمده از نوع امواج سالیتونی هستند که چکیده کامل

در این مقاله روش تحلیلی مبتنی بر معادله ریکاتی از نوع ------------------، جهت تبدیل معادله غیر خطی لاکشمینن-پوسیزین-دانیل به یک معادله معمولی غیرخطی و به‌دست آوردن جواب‌های سالیتونی آن، مورد مطالعه قرار گرفته شده است. جواب های به‌دست آمده از نوع امواج سالیتونی هستند که با استفاده از تغییر متغیر موجی حاصل شدهاند. این جواب‌ها از آنجایی که با معرفی ساختار جدیدی از شکل جواب‌ها، حاصل شده‌اند جدید بوده و این ایده میتواند برای بسیاری از معادلات غیر خطی مراتب بالا که یافتن جواب برای آنها مشکل است، مورد استفاده قرار گیرد. پرونده مقاله

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2 - Numerical solution for one-dimensional independent of time Schrödinger Equation
Z. Yousefian N. Shadmani

In this paper, one of the numerical solution method of one- particle, one dimensional timeindependentSchrodinger equation are presented that allows one to obtain accurate bound state eigenvalues and functions for an arbitrary potential energy function V(x).For each case چکیده کامل

In this paper, one of the numerical solution method of one- particle, one dimensional timeindependentSchrodinger equation are presented that allows one to obtain accurate bound state eigenvalues and functions for an arbitrary potential energy function V(x).For each case, we draw eigen functions versus the related reduced variable for the correspondingenergies. The paper ended with a comparison of the result obtained by the numerical solutions withthose obtained via the analytical solutions. The agreement between the results obtained by analyticalsolution method and numerical solution is represents the top Numerov method for numerical solutionSchrodinger equation with different potentials energy. پرونده مقاله

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3 - Investigation of analytical and numerical solutions for one-dimensional independent-oftime Schrödinger Equation
Z. Yousefian Molla Gh. Islampour

In this paper, the numerical solution methods of one- particale, one dimensional time- independentSchrodinger equation are presented that allows one to obtain accurate bound state eigen values andeigen functions for an arbitrary potential energy function V(x). These me چکیده کامل

In this paper, the numerical solution methods of one- particale, one dimensional time- independentSchrodinger equation are presented that allows one to obtain accurate bound state eigen values andeigen functions for an arbitrary potential energy function V(x). These methods included the FEM(Finite Element Method), Cooly, Numerov and others. Here we considered the Numerov method inmore details. For this purpose, we first reformulated the Shrodinger equation using dimensionlessvariables, the estimating the initial and final values of the reduced variable xr and the value ofintervals sr, and finally making use of Q-Basic or Spread Sheet computer programs to numericallysolved the equation. For each case, we drew the eigen functions versus the related reduced variablefor the corresponding energies. The harmonic oscillator, the Morse potential, and the H-atom radialSchrodinger equation, … were the examples considered for the method. The paper ended with acomparison of the result obtained by the numerical solutions with those obtained via the analyticalsolutions. The agreement between the results obtained by analytical solution method and numericalsolution for some Potential functions harmonic oscillator̕ Morse was represents the top Numerovmethod for numerical solution Schrodinger equation with different potentials energy. پرونده مقاله

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4 - حل تحلیلی معادله حاکم بر جریان غیر‌دارسی به روش ریاضی آنالیز هموتوپی
امیر حسین آروین محمد هادی فتاحی محمد صدقی اصل عباس محمدی

10.30495/wsrcj.2022.70054.11329

زمینه و هدف: روش آنالیز هموتوپی (HAM) اولین بار توسط لیائو (1992) برای حل معادلات تابعی پیشنهاد شد. این روش مبتنی بر هموتوپی است و یک راه‌حل تقریبی- تحلیلی برای معادلات تابعی ارائه می‌دهد. در سال‌های اخیر، این روش و اصلاحات آن به طور موثر برای حل طیف وسیعی از مسائل خطی چکیده کامل

زمینه و هدف: روش آنالیز هموتوپی (HAM) اولین بار توسط لیائو (1992) برای حل معادلات تابعی پیشنهاد شد. این روش مبتنی بر هموتوپی است و یک راه‌حل تقریبی- تحلیلی برای معادلات تابعی ارائه می‌دهد. در سال‌های اخیر، این روش و اصلاحات آن به طور موثر برای حل طیف وسیعی از مسائل خطی و غیرخطی در علوم کاربردی برای یافتن جواب‌های سری انواع مختلف معادلات غیر‌خطی، از جمله معادلات جبری‌، معادلات دیفرانسیل معمولی، معادلات دیفرانسیل جزئی و معادلات دیفرانسیل-انتگرال مورد استفاده قرار گرفته است .(Abbasbandy et al. 2006) هدف از این تحقیق ارائه یک حل تحلیلی زودیافت با دقت قابل قبول برای معادله غیرخطی جریان غیردارسی در محیطهای درشت دانه با استفاد از روش HAM می‌باشد.که محققان قبلی به انجام تحقیقات بیشتر در این زمینه توصیه کرده بودند.روش پژوهش: در این پژوهش ابتدا معادله حاکم بر جریان غیردارسی برای اولین بار به روش HAM حل شده است، سپس پروفیل های سطح آب معادله نهایی روش HAM به ازای 6 دبی ورودی با شرایط مرزی متفاوت در دو محیط متخلخل درشت‌دانه با مصالح گرد و تیزگوشه بدست آورده شد. و نتایج پروفیل سطح‌آب بدست آورده شده از روش HAM با داده‌های آزمایشگاهی صدقی‌اصل(2010) که درآزمایشگاه اشتوتگارت آلمان بدست آمده، مقایسه شده است. از تابع هدف نرمال (NOF) برای مقایسه جواب‌های روش HAM با داده‌های آزمایشگاهی صدقی‌اصل(2010) استفاده شده است. یافته‌ها: مقایسه نتایج روش HAM با داده‌های آزمایشگاهی صدقی‌اصل (2010) تحت شرایط مرزی بالادست و پایین‌دست به ازای دبی‌های متفاوت و با شیب نزدیک به افق S = 0.00001 صورت گرفته است. نتایج نشان داده‌اند که دبی های q=30 lit/s، با درصدخطای NOF برابر 0.000099828 در محیط متخلخل تیزگوشه وq =26.25 lit/s، با درصدخطای NOF برابر 0.000102162 در محیط متخلخل گردگوشه به ازای دبی‌های ورودی بیشتر، دقت بهتری نسبت به داده‌های آزمایشگاهی را دارند. این روش در شیب‌های افق دارای جواب‌های منطقی و پروفیل‌های سطح آب در روش HAM و داده‌های آزمایشگاهی در اکثر نقاط برهم منطبق و یا نزدیک به هم بوده است، در شیب‌های بالاتر به علت تاثیر شیب و نیروی گرانش دچار نوعی تورم در پروفیل جریان می‌شود که از مبحث جریان ماندگار و یکنواخت خارج است و خود نیازمند تحقیق دیگری است.نتایج: نتایج نشان داده که پروفیل سطح آب در بیشتر موارد به هم نزدیک هستند و نشان دهنده دقت روش توسعه یافته بر پایه آنالیز HAM می‌باشد. با این حال هنگامی که اختلاف تراز آب بالادست و پایین دست زیاد می‌شود، درصد خطا بالا می رود. به عبارت دیگر با افزایش گرادیان هیدرولیکی در محیط متخلخل خطا نیز افزایش می‌یابد. در نهایت با بررسی نتایج روش HAM نسبت به داده‌های آزمایشگاهی، میتوان نتیجه گرفت که این روش، در محیط‌ متخلخل با مصالح تیزگوشه نسبت به مصالح گردگوشه به ازای دبی‌های بیشتر دقت بهتری را نشان می دهد که به دلیل سرعت جریان و تخلخل بالا تر در این محیط می باشد. پرونده مقاله

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5 - A Method for Numerical Solution of Third-Kind Volterra Integral Equations Using Krall-Laguerre Polynomials
P. Jami E. Hashemizadeh

10.30495/ijim.2022.19201

The numerical solution of linear integral equations of third kind is discussed in various studies, but in the previous researches on this kind of equations only the analytical solution was investigated. Due to some limitations for this kind of solutions, in this paper w چکیده کامل

The numerical solution of linear integral equations of third kind is discussed in various studies, but in the previous researches on this kind of equations only the analytical solution was investigated. Due to some limitations for this kind of solutions, in this paper we propose a new method for numerical solution of linear integral equations of third kind. The proposed method is based on the approximation of the unknown function with Krall-Laguerre polynomials. This method has a simple computation with a quite acceptable approximate solution. Moreover, we obtain an estimate of the error bound for suggested method. Two examples are also presented to show the efficiency of the proposed method. پرونده مقاله

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6 - Exact Closed-Form Result for the Heat Transfer From Convecting-Radiating Fin of Rectangular Shape
E. Shivanian F. Sohrabi

In this letter, the problem of determining heat transfer from convecting-radiating fin of rectangular shape is investigated. We consider steady conduction in the fin and neglect radiative exchange between adjacent fins and between the fin and its primary surface. It is چکیده کامل

In this letter, the problem of determining heat transfer from convecting-radiating fin of rectangular shape is investigated. We consider steady conduction in the fin and neglect radiative exchange between adjacent fins and between the fin and its primary surface. It is demonstrated that the governing fin equation is exactly solvable. The exact, closed-form analytical solutions in implicit form are convenient for physical interpretation and optimization for maximum heat transfer. پرونده مقاله

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7 - Barrier options pricing of fractional version of the Black-Scholes ‎model‎
M. A. Mohebbi &lrm;Ghandehari&lrm; M. &lrm;Ranjbar&lrm;

In this paper two different methods are presented to approximate the solution of the fractional Black-Scholes equation for valuation of barrier option. Also, the two schemes need less computational work in comparison with the traditional methods. In this work, we propos چکیده کامل

In this paper two different methods are presented to approximate the solution of the fractional Black-Scholes equation for valuation of barrier option. Also, the two schemes need less computational work in comparison with the traditional methods. In this work, we propose a new generalization of the two-dimensional differential transform method and decomposition method that will extend the application of this methods for pricing barrier options of fractional version of the Black-Scholes model. Undoubtedly this model is the most well known model for pricing financial derivatives. This methods finds the analytical solution without any discretization or additive assumption. the approximate analytic solution is calculated in the form of convergent series with easily computable components, to solve the fractional Black-Scholes &lrm;equation. پرونده مقاله

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8 - Analytical and Numerical Study of Pre-Stress Effect in Piezoelectric Sandwich Type Ultrasonic Transducer
Hamidreza Nadri Mahdi Shaban Abbas Pak

10.30495/admt.2021.1904847.1204

In this paper, the effect of pre-stress condition on the resonance frequency of the transducer is studied by using numerical and analytical methods. To compare the obtained results, two sandwich-type transducers with nominal frequency of 25 kHz and 30 kHz are considered چکیده کامل

In this paper, the effect of pre-stress condition on the resonance frequency of the transducer is studied by using numerical and analytical methods. To compare the obtained results, two sandwich-type transducers with nominal frequency of 25 kHz and 30 kHz are considered. Experimental determination of pre-stress value in transducer is described and measured. Then resonance frequency of transducers in the presence of pre-stress is determined by impedance analyser. Numerical analysis is conducted by modelling three-dimensional transducer in details at ABAQUS software. The resonance frequency is determined with and without pre-stress. The FE results show that by applying pre-stress on the transducers, the resonance frequency of transducers decreased. Furthermore, the FE results are very close to experimental results. Furthermore, a systematic analytical solution is presented based on one-dimensional wave propagation. The resultant displacement for each sub-section of the transducer is calculated and then all of them are assembled and solved by considering the continuity conditions of displacement and force components. It is found that pre-load condition that is produced by central bolt reduces resonance frequency of the transducer. The obtained analytical results provide fast and reliable model for predicting resonance frequency of transducer. پرونده مقاله

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9 - Size-Dependent Forced Vibration Analysis of Three Nonlocal Strain Gradient Beam Models with Surface Effects Subjected to Moving Harmonic Loads
K Rajabi Sh Hosseini Hashemi A.R Nezamabadi

10.22034/jsm.2019.664215

The forced vibration behaviors are examined for nonlocal strain gradient nanobeams with surface effects subjected to a moving harmonic load travelling with a constant velocity in terms of three beam models namely, the Euler-Bernoulli, Timoshenko and modified Timoshenko چکیده کامل

The forced vibration behaviors are examined for nonlocal strain gradient nanobeams with surface effects subjected to a moving harmonic load travelling with a constant velocity in terms of three beam models namely, the Euler-Bernoulli, Timoshenko and modified Timoshenko beam models. The modification for nonlocal strain gradient Timoshenko nanobeams is exerted to the constitutive equations by exclusion of the nonlocality in the shear constitutive relation. Some analytical closed-form solutions for three nonlocal strain gradient beam models with simply supported boundary conditions are derived by using the Galerkin discretization method in conjunction with the Laplace transform method. The effects of the three beam models, the nonlocal and material length scale parameters, the velocity and excitation frequency of the moving harmonic load on the dynamic behaviors of nanobeams are discussed in some detail. Specifically, the critical velocities are examined in some detail. Numerical results have shown that the aforementioned parameters are very important factors for determining the dynamic behavior of the nanobeams accurately. پرونده مقاله

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10 - Determination of the Effective Parameters for Perforated Functionally Graded Plates with Polygonal Cutout by Analytical Solution
M Jafari M. H Bayati Chaleshtari H Abdolalian

10.22034/jsm.2019.584898.1395

This paper investigates the moments and stress resultants from infinite FG laminates with different polygonal cutouts subject to uniaxial tensile load. The analytical solution used for the calculation of stress resultants and moments is the basis of the complex-variable چکیده کامل

This paper investigates the moments and stress resultants from infinite FG laminates with different polygonal cutouts subject to uniaxial tensile load. The analytical solution used for the calculation of stress resultants and moments is the basis of the complex-variable method and conformal mapping function. The impact of various factors, namely cutout orientation angle, cutout aspect ratio as well as the cutout corner curve on stress distribution and moment resultants is studied. The effect of the aforementioned parameters around triangular, square, pentagonal and hexagonal cutout is analyzed. The mechanical characteristics of the graded plates are hypothesized to vary throughout the thickness exponentially. Finite element numerical solution is employed to examine the results of the present analytical solution. This comparison showed a favorable agreement level among the acquired analytical and numerical outcomes. پرونده مقاله

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11 - Bending Analysis of Laminated Composite Plates with Arbitrary Boundary Conditions
A.M Naserian Nik M Tahani

It is well known that for laminated composite plates a Levy-type solution exists only for cross-ply and antisymmetric angle-ply laminates. Numerous investigators have used the Levy method to solve the governing equations of various equivalent single-layer plate theories چکیده کامل

It is well known that for laminated composite plates a Levy-type solution exists only for cross-ply and antisymmetric angle-ply laminates. Numerous investigators have used the Levy method to solve the governing equations of various equivalent single-layer plate theories. It is the intension of the present study to introduce a method for analytical solutions of laminated composite plates with arbitrary lamination and boundary conditions subjected to transverse loads. The method is based on separation of spatial variables of displacement field components. Within the displacement field of a first-order shear deformation theory (FSDT), a laminated plate theory is developed. Two systems of coupled ordinary differential equations with constant coefficients are obtained by using the principle of minimum total potential energy. Since the procedure used is simple and straightforward it can, therefore, be adopted in developing higher-order shear deformation and layerwise laminated plate theories. The obtained equations are solved analytically using the state-space approach. The results obtained from the present method are compared with the Levy-type solutions of cross-ply and antisymmetric angle-ply laminates with various admissible boundary conditions to verify the validity and accuracy of the present theory. Also for other laminations and boundary conditions that there exist no Levy-type solutions the present results may be compared with those obtained from finite element method. It is seen that the present results have excellent agreements with those obtained by Levy-type method. پرونده مقاله

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12 - A Zigzag Theory with Local Shear Correction Factors for Semi-Analytical Bending Modal Analysis of Functionally Graded Viscoelastic Circular Sandwich Plates
M Shariyat M.M Alipour

Free bending vibration analysis of the functionally graded viscoelastic circular sandwich plates is accomplished in the present paper, for the first time. Furthermore, local shear corrections factors are presented that may consider simultaneous effects of the gradual va چکیده کامل

Free bending vibration analysis of the functionally graded viscoelastic circular sandwich plates is accomplished in the present paper, for the first time. Furthermore, local shear corrections factors are presented that may consider simultaneous effects of the gradual variations of the material properties and the viscoelastic behaviors of the materials, for the first time. Moreover, in contrast to the available works, a global-local zigzag theory rather than an equivalent single-layer theory is employed in the analysis. Another novelty is solving the resulted governing equations by a power series that may cover several boundary conditions. To extract more general conclusions, sandwich plates with both symmetric and asymmetric (with a bending-extension coupling) layups are considered. Results are validated by comparing some of them with results of the three-dimensional theory of elasticity, even for the thick plates. Influences of various geometric and material properties parameters on free vibration of the circular sandwich plates are evaluated in detail in the results section. پرونده مقاله

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13 - Inhomogeneity Material Effect on Electromechanical Stresses, Displacement and Electric Potential in FGM Piezoelectric Hollow Rotating Disk
A Ghorbanpour Arani H Khazaali M Rahnama M Dadkhah

In this paper, a radially piezoelectric functionally graded rotating disk is investigated by the analytical solution. The variation of material properties is assumed to follow a power law along the radial direction of the disk. Two resulting fully coupled differential e چکیده کامل

In this paper, a radially piezoelectric functionally graded rotating disk is investigated by the analytical solution. The variation of material properties is assumed to follow a power law along the radial direction of the disk. Two resulting fully coupled differential equations in terms of the displacement and electric potential are solved directly. Numerical results for different profiles of inhomogeneity are also graphically displayed. پرونده مقاله

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14 - Determination of Optimal Parameters for Finite Plates with a Quasi-Square Hole
M Jafari M.H Bayati Chaleshtari E Ardalani

This paper aims at optimizing the parameters involved in stress analysis of perforated plates, in order to achieve the least amount of stress around the square-shaped holes located in a finite isotropic plate using metaheuristic optimization algorithms. Metaheuristics m چکیده کامل

This paper aims at optimizing the parameters involved in stress analysis of perforated plates, in order to achieve the least amount of stress around the square-shaped holes located in a finite isotropic plate using metaheuristic optimization algorithms. Metaheuristics may be classified into three main classes: evolutionary, physics-based, and swarm intelligence algorithms. This research uses Genetic Algorithm (GA) from evolutionary algorithm category, Gravitational Search Algorithm (GSA) from physics-based algorithm category and Bat Algorithm (BA) from Swarm Intelligence (SI) algorithm category. The results obtained from the present study necessitate the determination of the actual boundary between finite and infinite plate for the plates with square-shaped holes. The design variables such as bluntness, hole orientation, and plate dimension ratio as effective parameters on stress distribution are investigated. The results obtained from comparing BA, GA and GSA indicate that BA as SI algorithm category competitive results, proper convergence to global optimal solution and more optimal stress level than the two mentioned algorithms. The obtained results showed that the aforementioned parameters have a significant impact on stress distribution around a square-shaped holes and that the structure’s load-bearing capability can be increased by proper selection of these parameters without needing any change in material properties. پرونده مقاله

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15 - New Method of Determination for Pressure and Shear Frictions in the Ring Rolling Process as Analytical Function
M.R Zamani

Ring rolling is one of the most significant methods for producing rings with highly precise dimensions and superior qualities such as high strength uniformity, all accomplished without wasting any materials. In this article, we have achieved analytical formulas for calc چکیده کامل

Ring rolling is one of the most significant methods for producing rings with highly precise dimensions and superior qualities such as high strength uniformity, all accomplished without wasting any materials. In this article, we have achieved analytical formulas for calculating the pressure and shear friction over the contact arcs between the rollers and ring in the ring rolling process for the material in general nonlinear hardening property. We have also asserted the best mathematical model to predict friction for rolling processes. The method we use is based on calculating the analytical stress distribution. In other words, by using of Saint-Venan principal the stress components are calculated as analytical functions. Once that is accomplished, the pressure and shear traction over the rollers are able to be analyzed. The crucial characteristics which set apart this study from other studies are the investigation of the effects of the speed with which rollers are fed, and resulting ring velocity. With normal and shear friction, those characteristics cannot be investigated by other methods such as the slab method, upper bound, etc. Also, results show the effects of material hardening properties, radius of rollers and thickness reduction under pressure, and shear friction distributions. پرونده مقاله

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16 - Semi-Analytical Solution for Free Vibration Analysis of Thick Laminated Curved Panels with Power-Law Distribution FG Layers and Finite Length Via Two-Dimensional GDQ Method
V Tahouneh M.H Naei

This paper deals with free vibration analysis of thick Laminated curved panels with finite length, based on the three-dimensional elasticity theory. Because of using two-dimensional generalized differential quadrature method, the present approach makes possible vibratio چکیده کامل

This paper deals with free vibration analysis of thick Laminated curved panels with finite length, based on the three-dimensional elasticity theory. Because of using two-dimensional generalized differential quadrature method, the present approach makes possible vibration analysis of cylindrical panels with two opposite axial edges simply supported and arbitrary boundary conditions including Free, Simply supported and Clamped at the curved edges. The material properties vary continuously through the layers thickness according to a three-parameter power-low distribution. It is assumed that the inner surfaces of the FG sheets are metal rich while the outer surfaces of the layers can be metal rich, ceramic rich or made of a mixture of two constituents. The benefit of using the considered power-law distribution is to illustrate and present useful results arising from symmetric and asymmetric profiles. The effects of geometrical and material parameters together with the boundary conditions on the frequency parameters of the laminated FG panels are investigated. The obtained results show that the outer FGM Layers have significant effects on the vibration behavior of cylindrical panels. This study serves as a benchmark for assessing the validity of numerical methods or two-dimensional theories used to analysis of laminated curved panels. پرونده مقاله

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17 - Analytical Solution for Response of Piezoelectric Cylinder Under Electro-Thermo-Mechanical Fields
S Golabi J Jafari Fesharaki

This paper presents an analytical solution for response of a piezoelectric hollow cylinder under two-dimensional electro thermo mechanical fields. The solution is based on a direct method and the Navier equations were solved using the complex Fourier series. The advanta چکیده کامل

This paper presents an analytical solution for response of a piezoelectric hollow cylinder under two-dimensional electro thermo mechanical fields. The solution is based on a direct method and the Navier equations were solved using the complex Fourier series. The advantage of this method is its generality and from mathematical point of view, any type of the thermo mechanical and electrical boundary conditions can be considered without any restrictions. The thermo mechanical and electrical displacements are assumed that vary in radial and circumferential directions. Finally, three examples were considered to confirm the results and investigate the effect of in-phase and opposite-phase electro thermo mechanical boundary loads on two-dimensional electro thermo mechanical behavior of piezoelectric hollow cylinder. The results are compared with the previous work and FEM analysis. The main result of this study is that, by applying a proper distribution of thermal, electrical and mechanical fields, the distributions of electric and mechanical displacement, thermal and mechanical stresses can be controlled. پرونده مقاله

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18 - طراحی جاذب دینامیکی به منظور کاهش ارتعاشات بال یک سازه پرنده: بررسی تجربی و عددی
آرش نعیمی آبکناری محمدرضا صالحی برزگر محمد مهدی خیری خواه

بال یک سازه پرنده، از قسمت‌های اصلی و مهم برای کنترل و هدایت آن در مسیر صحیح می‌باشد. در این مقاله ابتدا به منظور بررسی رفتار ارتعاشی بال، معادلات حرکت آن در حین باز شدن تا توقف به روش تحلیلی استخراج و سپس با نتایج تست تجربی و همچنین نتایج حاصل از نرم‌افزار اَدَمز مقایس چکیده کامل

بال یک سازه پرنده، از قسمت‌های اصلی و مهم برای کنترل و هدایت آن در مسیر صحیح می‌باشد. در این مقاله ابتدا به منظور بررسی رفتار ارتعاشی بال، معادلات حرکت آن در حین باز شدن تا توقف به روش تحلیلی استخراج و سپس با نتایج تست تجربی و همچنین نتایج حاصل از نرم‌افزار اَدَمز مقایسه می‌گردد. در حین توقف بین بال و بدنه، برخوردی صورت گرفته که باعث اعمال یک تحریک تصادفی و ناخواسته بر بال می‌شود. در این تحقیق، برای کاهش دامنه ارتعاش و نوسانات ایجاد شده از برخورد بال به بدنه سازه پرنده در کمترین زمان ممکن، یک جاذب دینامیکی از جنس تفلون طراحی، تحلیل و تست شده است. این جاذب با استفاده از استهلاک خشک انرژی ناشی از برخورد بال را از بین می‌برد. در انتها با تحلیل تأثیر پارامترهایی نظیر ضریب اصطکاک، جنس پین بال، جنس مستهلک‌کننده خشک و میزان سطح تماس، به بهینه‌سازی عملکرد جاذب دینامیکی پرداخته می‌شود. نتایج به دست آمده نشان می‌دهد که با افزایش ضریب اصطکاک و در نتیجه افزایش نیروی اصطکاک، زاویه بازگشت و دامنه نوسانات بال کاهش یافته و ارتعاشات ناخواسته‌ی ایجاد شده در سیستم به حداقل می‌رسد. پرونده مقاله

دسترسی آزاد مقاله

19 - Analysis of Circular Reinforced Tunnels by Analytical Approach
Ahmad Fahimifar Masoud Ranjbarnia

This paper addresses the problem of quantifying the mechanical contribution of rockbolts installed systematically around tunnels (regularly spaced around the tunnel) excavated in rock masses. Assuming that the mechanical contribution of grouted rockbolts is that of incr چکیده کامل

This paper addresses the problem of quantifying the mechanical contribution of rockbolts installed systematically around tunnels (regularly spaced around the tunnel) excavated in rock masses. Assuming that the mechanical contribution of grouted rockbolts is that of increasing internal pressure within a broken rock mass, a new procedure for computation of ground response curves for a circular tunnel excavated in strain softening material and then reinforced with systematically active grouted rockbolts is presented. In this work, the equation of the ground response curve for a tunnel which has been reinforced with passive grouted rockbolts is also derived. The proposed model allows one to take into account the effect of the distance of the bolted section to the tunnel face, the effect of increasing rockbolts spacing, the influence of increasing pretension load in calculating of the ground response curve, and the effect of increasing the cross-section area of rockbolts. The results show that decreasing rockbolts spacing increases the support system stiffness rather than preloading of them. پرونده مقاله

دسترسی آزاد مقاله

20 - Heat Conduction in Spherical Composite Vessels
م. نوروزی ا. امیری دلویی م. سلیسپور

This paper presents an exact analytical solution for two-dimensional conductive heat transfer in spherical composite pressure vessels .The vessels are in spherical shape and fibers are winded in circumferential direction. The analytical solution is obtained under the ge چکیده کامل

This paper presents an exact analytical solution for two-dimensional conductive heat transfer in spherical composite pressure vessels .The vessels are in spherical shape and fibers are winded in circumferential direction. The analytical solution is obtained under the general boundary conditions which consist of convection, conduction and radiation inside/outside of vessel. The heat transfer equation for orthotropic conduction in spherical coordinates is derived and solved using separation of variables method based on the Legendre and Euler functions. Here, the effect of fiber's angle on heat diffusion in orthotropic spherical pressure vessels is investigated in detail. These results can be used extensively for analyzing the thermal stress in this kind of vessels. پرونده مقاله

دسترسی آزاد مقاله

21 - Resolution composite shell with a layer of piezoelectric vibration analysis
اکبر علی بیگلو عبدالمجید کنی

In this paper, the vibration of composite cylindrical shell with piezoelectric layers in the interior and exterior surfaces is investigated. The composite shell without piezoelectric layers can be studied and compared the results with the results of other researchers, t چکیده کامل

In this paper, the vibration of composite cylindrical shell with piezoelectric layers in the interior and exterior surfaces is investigated. The composite shell without piezoelectric layers can be studied and compared the results with the results of other researchers, the cylindrical shell laminated with layers of piezoelectric vibration checked. The result is a three-dimensional elasticity equations relationships because they do not apply any approximate gain are quite analytical. Shells intended, is closed and has restricted the mainstays in the end it was simple, and the results for the ratio of the radius and the radius of the different thickness are obtained پرونده مقاله

فهرست مقالات Analytical solution

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