bluuebunny/crossref_metadata_2025 huggingface dataset:
Types of momentum defect diffusion at the begining of the wake and wake establishment zone for the coupled wake and comparison with the isolated wake
Authors: Bich Ngoc Hoang Thi
Published: April 2018

The article [10] has presented the necessity of the classification into two types: Isolated wakes and coupled wakes. In this report, different types of momentum defect diffusion at the beginning of wake are analyzed for the two types of coupled wake and isolated wake. According to ·numerical results obtained, we analyses the existence - long or short - of the wake establishment zone before the wake established zone, and this zone is very different between isolated wake and coupled wake.
Dynamic absorber for self-excited oscillation of the rectangular thin plate with creep
Authors: Da Hoang Van
Published: April 2018

None
Measurement of natural tectonic state of stress in rock foundation by back calculation method with deformation of tunnel contour
Authors: Hanh Nghiem Huu
Published: April 2018

None
INTERACTION BETWEEN PARAMETRIC AND FORCED OSCILLATIONS IN A QUASI-LINEAR OSCILLATING SYSTEM
Authors: Chi Tran Kim , Dinh Nguyen Van
Published: April 2018

None
Natural frequency analysis of cracked beam
Authors: Khiem Nguyen Tien , Mai Dao Nhu
Published: April 2018

The model of cracked one-dimensional structure has been treated as two uniform beams connected by an equivalent rotation spring at the crack location. The frequency equation in bending vibration of the system is obtained in general form for arbitrary boundary conditions at both ends used for analysing the natural frequencies as function of crack position and magnitude. This investigation allows to carry out general procedure for identification of position as well as magnitude of the crack by natural frequencies measured experimentally.
The forms of the shell with zero bending stresses subjected to hydrostatic pressure and other loads
Authors: Nhu Ngo Huong
Published: April 2018

None
Numerical evaluation of periodic transverse vibration of elastic connecting rods in a six-link mechanism
Authors: Khang Nguyen Van , Khiem Vu Van
Published: April 2018

Application of the substructure method and d'Alembert's principle to deriving the differential equation of motion of a six-link mechanism with two elastic connecting rods is presented. In the case of stationary motion, the generalized Ritz's method has been applied to obtain system of linear differential equations with periodic coefficients. We have written computer programs to check conditions of dynamic stability and to find periodic solutions of the obtained equations. Numerical examples are given and from which the effect of elastic factors on articulation reactions is evaluated.
Wind field over complex terrain and air quality modeling
Authors: Hai Duong Ngoc , Diep Nguyen Van , Duc Nguyen The
Published: April 2018

None
The convergence of the corrosion-fatigue curve family and its applications in estimating the life lost of metals in fatigue experiments
Authors: Phuc Phan Huu
Published: April 2018

An approach to establish the no corrosion - fatigue curve is introduced. Based on this new approach, equations that describe the heat effect and life lost when determining the fatigue strength of metals may be established, also the reliability of the traditional fatigue curve can be assessed.
On the instability of a mechanical system of 2-degree of freedom taking into account the resisting force
Authors: Tru Vu Quoc , Bich Nguyen Dang
Published: April 2018

None
Approximate technique for determining parameters of the miniature mechanical systems
Authors: Di Phan Nguyen
Published: April 2018

None
Seiche in the Gulf of Tonkin
Authors: Ninh Pham Van , Ngoc Duyet Tran Thi
Published: April 2018

Steichen in the Gulf of Tonkin has been studied by numerical modelling based on the two-dimensional nonlinear shallow water equations system with liquid boundary condition given in the form of forced oscillation. The main proper periods have been defined as follows: 23-25 hours, 1-12 hours, 5-7 hours, 2-4 hours. Among them the 23 hours period is the most evident. The obtained results coincide with observed ones at the long shore hydrometeological stations of the Gulf.
Estimating the interaction between a storm surge and a tide
Authors: Quynh Do Ngoc , Viet Lien Nguyen Thi , Manh Dinh Van
Published: April 2018

In the paper the using numerical hydro dynamical model for the researching the non-linear interaction between a storm surge and a tide in the Gulf of Tonkin, where the storm surge and the tide are of the same rank in value is presented. The results of calculating denote that the interaction lowers a total sear level at high tide and rises a total sea-level at low tide.
The role of the material fracture properties in the size-effect law of concrete structures
Authors: Tu V. Tran
Published: April 2018

The size effect of the nominal stress at failure in concrete structures is dealt within general. An existence of a rather large fracture process zone in front of crack tip is proved to be the main reason leading to the size effect of the nominal strength. On the basis of the new general size-effect law and numerical results of fracture propagation, a particularly proposed size effect law for beams in bending is developed, in which the role of each material fracture characteristic, especially the shape of the stress - crack opening curve, is elaborated clearly.
Probabilistic criterion for Gausian equivalent linearization
Authors: Anh N. D. , Schiehlen W.
Published: April 2018

Within the scope of Gaussian equivalent linearization, a new probabilistic criterion for determining the coefficients of the linearized equivalent equation is proposed to treat stationary response of non-linear systems under zero mean Gaussian ro.nd.om excitation. Application to the Duffing oscillate subjected to white noise is presented that shows significant improvement over corresponding accuracy of the classical Gaussian equivalent linearization for both weak and strong non-linear.
Determination of beams's parameters with lumped mass by using measurement data of vibrations
Authors: Menh Nguyen Cao , Toan Tran Trong
Published: April 2018

In this paper the transverse vibration of the clamped-free beam with lumped mass is investigated. From that the inverse problem for determining the length of the beam on the basis of measurement data of beam’s vibration with changing mass is solved by numerical method. The computer programs for the problem are to be applied to some examples and the obtained results are acceptable. The common solution for problems with different lumped masses is chosen as desirable result.
Methods for stability and instability of the solution of one non-linear differential equation
Authors: Bich Nguyen Dang , Thong Nguyen Vo
Published: April 2018

When research on instability states of tall and flexible structures is carried out, the solutions of non-linear differential equations have to be investigated. Although the fully analytical solutions of the moving rule of the structures cannot be found, but based on the conditions applied to the parameters of the moving differential equations the authors have studied the characteristics of the solutions when t→∞. Then the instability of the structures may be investigated, and the stability conditions can be concluded. This is the content which this paper would like to present.
Gyroscop on the accelerated rotative basis
Authors: Huyen Pham , Mau Nguyen Thanh
Published: April 2018

None
Free convection flow in vertical cylinder with heat sources of power law fluid
Authors: Quang Vu Duy , Que Nguyen Van
Published: April 2018

In this paper the free convection flow of power law fluid in cylindrical channel with heat sources is investigated. The heat sources are in the fluid as well as inside the channel wall and are assumed constant and uniform distributed. The problem is solved by finite difference method. An asymptotic solution is given. The results with heat sources and without ones are compared.
Principle of compatibility applied to determination of reaction forces of kinematics pairs
Authors: Sanh Do
Published: April 2018

The aim of investigation is to present the principle of compatibility and to apply it for determining the reaction forces of kinematics pairs in mechanism. For this purpose the system is released from the given constrains. This resulted to increase the number of coordinates of the system. In order that the freed system realizes the motion of the given system, the coordinates of the freed system must satisfy some relations called the constraint equations. The reaction forces of the formed constraints are just the reaction forces, which are of interest to us.
Détermination de l'influence du trajet de déformation sur la courbe limite de formage
Authors: Thang Nguyen Nhat
Published: April 2018

The aim of this study is to predict the strain path influence on the forming limit diagram, from the limit stress curve. We consider two types of path, composed of two straight segments corresponding to stretching-tension and tension-stretching sequences.
Autosynchronization of two unbalance motors
Authors: Dinh Nguyen Van , Hung Nguyen Dac
Published: April 2018

In the present paper are presented some observations about the phenomenon of autosynchronization of two unbalance motors on a platform moving in a plane.
On a class of problems on unsteady flow of viscous-plastic fluids in pipe-line
Authors: Chi Nguyen Huu , Quang Vu Duy , Thanh Pham Hoai
Published: April 2018

Combining the quasi-stationary principle with velocity profile properties of respective steady flow and Sliozkin-Targ's approximation we introduce a method to solve a class of problems on unsteady flow of viscous-plastic fluid in pipe-lines. Using this method we solve the problems on unsteady pressure flow in the horizontal cylindrical tube. We also compare the obtained results with those of Tiabin showed in [1].
Stability of thin plates with compressible material in the theory of elastic-plastic processes
Authors: Dung Dao Van
Published: April 2018

In this paper is given a system of stability equations of elastic-plastic thin plates made of compressible material. These stability equations are a generalization of ones in the theory of elasticity and the simple processes theory.
A NUMERICAL SIMULATION OF MORPHOLOGICAL PROCESSES FOR A NAVIGATION CHANNEL
Authors: Diep Nguyen Van , Chung Dang Huu
Published: April 2018

The finite difference method was applied to simulate the morphological processes for a. navigation channel Mathematical equations were based on the SUTRENCH and PROFILE models proposed by L. C. van Rijn. The difficulties of treatment for bed boundary conditions were overcame flexibly by using the interpolation functions with high accuracy. The results obtained showed that the simulation is very suitable and able to be applied to practice problems.
Primary numerical study of the wave current interaction in river mouth regions
Authors: Ninh Pham Van , Quynh Do Ngoc , Manh Dinh Van
Published: April 2018

A hydro-numerical model based on the nonlinear shallow water equation system has been developed for calculation of the surface wave picture in river mouth regions. In the model the river flow ants the sea surface wave have been given at some river cross-section and at a deep sea boundary respectively and the real topography, wind and bottom friction stresses, orioles force also are taken into account. Calculated results for various river flows and sea waves with a simple river mouth topography show that the model can be used for studying interaction between waves and river currents in interesting areas.
Free convection flow of power law fluid in a vertical cylinder of finite height
Authors: Que Nguyen Van
Published: April 2018

A numerical solution has been presented for free convection flow of power law fluid in a vertical cylinder of finite height. The average velocity along the channel and the heat transfer have been calculated. Graphs of velocities and temperature are shown. The results show good agreement with analytic one in the asymptotic case.
Tính toán bằng phương pháp số lực thủy động tác dụng lên một phần tử cầu chuyển động tịnh tiến
Authors: Tri Bui Dinh
Published: April 2018

None
Convection in binary mixture with free surface
Authors: Can Ngo Huy , Ha Tran Thu
Published: April 2018

None
Interaction between parametric and forced oscillations in fundamental resonance
Authors: Dinh Nguyen Van
Published: April 2018

None
A form of equation of motion of a mechanical system
Authors: Sanh Do
Published: April 2018

None
Calculating tidal prediction in the Gulf of Tonkin
Authors: Quynh Do Ngoc , Viet Lien Nguyen Thi
Published: April 2018

In the paper the using numerical hydro dynamical model for the tidal prediction in the Gulf of Tonkin is presented. The results of prediction are compared with the Tidal Table at some coastal station. The comparison proves that the prediction model suits practice.
On the parametric transverse vibrations of continuous beam on intermediate elastic supports under the action of moving body
Authors: Tho Do Xuan , Khang Nguyen Van
Published: April 2018

In this text the method of substructures [2] is applied for establishing the vibration equation of beam under the action of moving body. Later an algorithm is built to solve the vibration equation received. From this algorithm a computer program is set up with TURBO PASCAL 6.0 language.
Sensitivity analysis for a problem of optimal structure design
Authors: Nhu Ngo Huong
Published: April 2018

On the basis of theory of structure sensitivity analysis, the gradient – projection method and the finite element method, a detailed and effective algorithm of determination of the sensitivity-vector for the optimal structure design problem is proposed. Numerical results illustrating the program corresponding to this algorithm have been given for some plane frames.
Canonical equations for a constrained mechanical system
Authors: Sanh Do
Published: April 2018

None
A numerical method for shallow shell vibration and stability problems
Authors: Chinh Tran Duc
Published: April 2018

None
Weak self-sustained system under the actions of less weak excitations
Authors: Dinh Nguyen Van
Published: April 2018

It has been known that, in several cases, to study quasi-linear oscillating system, the degrees of smallness of various factors must be distinguished in detail [2-7]. To affirm again this interesting remark, we shall examine a weak (of order ε2) self-sustained system subjected to less weak (of order ε) excitations in resonance cases. It will be seen that the system considered is enhanced.
On the problem of heat and mass transfer in thermal non-isolated reservoir
Authors: Hai Duong Ngoc
Published: April 2018

None
On the problems of nonhomogeneous and anisotropic elastic layer-composite plates
Authors: Bich Dao Huy
Published: April 2018

Using the homogenization method problems of nonhomogeneous and anisotropic elastic layer composite plates reduce to the problems of homogeneous and anisotropic elastic plates. The formulae of effective modulus theory determining material behaviors in this cases are given and can be checked by experimental data. Obtained results allow to analyze static and dynamic problems of composite plates by well - know methods.
Sublayer effect near the wall in the presence of Svedov-Bingham flow
Authors: Chi Nguyen Huu , Thanh Pham Hoai
Published: April 2018

In this paper we study the stationary flow of viscous-plastic fluid in the horizontal cylindrical tube (Svedov Bingham's flow) with the assumption of existence of the viscous adherent sub layer near the wall. The obtained results are estimated and compared with those of Svedov - Bingham flow. We also inspect the "near the wall effect" which was showed in the work of Smoldurev & Xaponov and have some notes and estimation about it.
A criteria of ideality of mechanical constraints in principle of compatibility
Authors: Phong Dinh Van
Published: April 2018

None
Longitudinal shock of two elastic bars with one spherical end
Authors: An Nguyen Thuc , To Nguyen Dang , Son Nguyen Hung
Published: April 2018

In this paper, authors researched a problem about longitudinal shock of two free elastic bars with one spherical end in interval 0 < t < 2l2/ a2 . Authors defined wave function in the bars, tress, strain and velocity of every section. Also authors defined the force of compression caused by shock of two bars.
Energetic criterion in general elastic-plastic fracture mechanics
Authors: Dan Bui Huu
Published: April 2018

From the analyzing the equation of energy balance for cracked bodies during the crack growth the energetic criterion is formulated for general elastic-plastic fracture mechanics. The numerical procedure should be realized by using the slip model of polycrystalline plasticity and the experimental data.
Convective motion in binary mixture
Authors: Can Ngo Huy
Published: April 2018

None
Theory of two-phase flow of fluid with rigid ellipsoidal particles
Authors: Diep Nguyen Van , Phan Nguyen Hong
Published: April 2018

In the paper [1] the general continuum theory has been developed for two phase of fluid with deformable particles of arbitrary form, where the micro deformation of the particles and the relative motion between phases are taken into account. The extended theory of irrational flow of fluid caused by a moving deformable body has been used to obtain the general expressions for the generalized induced mass tensors.
Linearization method in reliability problem
Authors: Pho Nguyen Van , Thach Le Ngoc
Published: April 2018

A method for calculation of reliability of mechanical system by linearization of conditional functions of joint probability around its expectation is considered. A numerical example is given.
Nonlinear oscillations in systems with large static deflection of elastic elements
Authors: Dao Nguyen Van
Published: April 2018

In mechanical systems the static deflection of the elastic elements is usual not appeared in the equations of motion. The reason is that either a linear model of the elastic elements or their too small static deflection assumption was accepted. In the present paper both nonlinear model of elastic elements and their large static deflection are considered, so that the nonlinear terms in the equation of motion appear with different degrees of smallness. In this case the nonlinearity of the system depends not only on the nonlinear characteristic of the elastic element but on its static deflection. The distinguishing feature of the system under consideration is that if the elastic element has soft characteristic, the nonlinear system also belongs to the soft one. If the elastic element has hard characteristic, the system may be either soft or hard or neutral type, depending on the relation between the parameters of the elastic element and its static deflection.
Stability of the inverse pendulum with the hanging point in multifrequency motion
Authors: Dinh Nguyen Van
Published: April 2018

In the present paper, the stability of the upper equilibrium position of the pendulum is examined. It is found that if the hanging point undergoes vertical complicated oscillating motion the different components of the motion law reinforce their actions so that the mentioned equilibrium position becomes more stable. On the contrary, if the hanging point moves in the vertical plane the inverse pendulum is less stable under the influence of the horizontal component of the motion.
Simulation on personal computer of dynamic system having nonlinear damping force
Authors: Le Nguyen Nhat
Published: April 2018

A dynamic system having nonlinear damping force and connected with a spring-damper element is simulated on personal computer. It is considered the influences of different parameters on the dynamic response of this system.
Stability of two-dimensional sediment flow down an inclined plane
Authors: Diep Nguyen Van , Chung Dang Huu
Published: April 2018

In this paper the authors have studied the instability of 2-D flow with sediment transport, which is based on the generalized diffusion theory. The authors have constructed the boundary conditions of the bed concentration and diffusion flux at the free surface for dosing equations system. After that the authors have considered the instability and obtained the neutral-curve of stability in the plane (R1 k). The obtained results show that if there is no suspended sediment, the result will be identical to Chia-Shun Yih's.
Một phương pháp kiểm tra sự ổn định của các công trình được trình bày theo phương pháp phần tử hữu hạn
Authors: Mai Le Van
Published: April 2018

None
Nonlinear model simulation of ship motion
Authors: Dao Nguyen Van
Published: April 2018

Nonlinear model simulation of coupling between heave-roll and pitch roll ship motions is considered by means of the asymptotic method of nonlinear mechanics. The purely vertical motion and vertical-angular motion and their stability are studied.
On a model of the nonlinear torsional vibration with variable generalized masses
Authors: Khang Nguyen Van , Son Tran Dinh
Published: April 2018

In this paper the establishment of the parametric vibration differential equations for a model of the nonlinear torsional vibration with variable generalized masses considered.
An extension of the E. Melan's shakedown theorem of the elasto-plastic structure
Authors: Pho Nguyen Van
Published: April 2018

None
The optimal height of aggregated steel beams
Authors: Truong Bui Quang
Published: April 2018

The author proposes a method to find out the optimal height of aggregated steel beam and the general formula to calculate the height which fully meets the hard and depends on load-form and link together in two ends of the beam.
Numerical calculation of the transverse vibrations of the multispan beams for moving load
Authors: Tho Do Xuan , Khang Nguyen Van
Published: April 2018

In this paper the numerical calculation of the transverse vibrations of the Multiplan beams for moving load is considered. A program has been worked out for the numerical integration of the motion equations on IBM-PC AT or XT. This program is useful in calculating the vibrations of the suspension bridges.
Sự hội tụ của phương pháp biến thể nghiệm đàn hồi trong lý thuyết quá trình biến dạng đàn dẻo
Authors: Bay Vu Khac
Published: April 2018

None
Simulation of stationary, non-normal random process
Authors: Menh Nguyen Cao , Tri Tran Duong
Published: April 2018

Simulation of stationary random processes specified by spectral density function and NonNormal probability density function has been rarely studied, though these processes are often met in both theory and practice. In this paper we consider a simulation method which can apply to the mention-above processes. The main idea based on the simulation of the Normal process and approximation of functions in the space of quadratic ally integrable functions. The numerical program for illustration of the method is written by Turbo - Pascal language.
Tự động hóa thiết kế các cơ sở đồ môđun truyền dẫn khí nén
Authors: Phuc Nguyen Thien , Khao Pham Van , Vinh Truong Si
Published: April 2018

None
The stability of flow with suspended sediment in an inclined channel of movable bed
Authors: Chung Dang Huu
Published: April 2018

In this work the author has studied the stability of flow with suspended sediment in an inclined channel of movable bed at different stages of flow. The obtained result shows that when the flow with suspended sediment is at the stage of deposition or erosion then the critical inclined angle is less than that one of homogeneous flow, e. g., the flow with suspended sediment is earlier unstable. If the exchange between suspended sediment and bed-load doesn't occur, the existence of sediment will not act on the condition of stability. In particular when C0 = 0 the classical result is obtained. The author would like to thank to Prof-Doctor Nguyen Van Diep for useful helping.
Một phương pháp giải bài toán ổn định các công trình được trình bày theo phương pháp phần tử hữu hạn
Authors: Mai Le Van
Published: April 2018

None
Một cách phát biểu mới hệ tiên đề của động lực học
Authors: Dao Nguyen Van
Published: April 2018

None
Về tự chấn của dầm có một bộ tắt chấn động lực
Authors: Dinh Nguyen Van , Cau Thai Manh
Published: April 2018

None
Xác định độ dày của vỏ tròn xoay không chịu uốn làm từ vật liệu phi đàn hồi dưới tác dụng của tải trọng cho trước
Authors: Nhu Ngo Huong
Published: April 2018

None
Phương pháp giải tổng hợp các bài toán dao động cưỡng bức và tự do của các công trình được trình bày theo phương pháp phần tử hữu hạn
Authors: Mai Le Van
Published: April 2018

None
Về một thuật toán điều khiển robot tự hành
Authors: Mau Nguyen Thanh
Published: April 2018

None
A class of deterministic external problems equivalent to stochastic external problems in the reliability theory of mechanical systems
Authors: Pho Nguyen Van
Published: April 2018

In this paper, the reliability of the Mechanic Systems is expressed under a new form. Then we propose au iterative method of computing of the  Reliability, and apply the obtained results to the some problems of Solid Mechanics.
The instability and the non-linear development of a flow in an inclined alluvial channel
Authors: Diep Nguyen Van , Hung Pham
Published: April 2018

In this paper the instability and the non-linear development of a flow in an inclined alluvial channel is investigated. It is shown that in linear case, at the critical value of inclined angle the arbitrary disturbance of the water surface and of velocity will be splinted in three modes. The non-linear differential equations describing the behavior of the modes when the time become large are obtained. Some solutions are analyzed.
Oscillations in the first order non-linear systems with delay. I. Autonomous systems
Authors: Anh Nguyen Dong , Khiem Nguyen Tien
Published: April 2018

Contrary to the systems without delay, in the first order systems with delay may be an undraped oscillation, which is constructed in this paper by means of the asymptotic method. The elf-excited oscillations in the Duffing and Van-De-Pol systems are considered.
A mathematical investigation of equations describing the sediment transport
Authors: Chung Dang Huu
Published: April 2018

In this work the mathematical problem of equations describing the sediment transport was studied. The results show that in the different cases of flow the set of equations has five characteristics, in which two of them are the rates of concentration propagation in the plane (x1t). The results of the other authors are only the particular cases in our work.
The instability of a flow in an inclined alluvial channel
Authors: Hung Pham
Published: April 2018

The instability of a flow in an inclined alluvial channel is investigated by the characteristic and the Fourier methods. It is shown that the bed form development could influence significantly on the stability of the water surface.
Mất ổn định và rẽ nhánh nhiệm của bài toán phi tuyến thanh thẳng chịu nén đúng tâm
Authors: Quang Do Quoc
Published: April 2018

None
Non-linear oscillations in first order systems with delay. II. Non-autonomous case
Authors: Anh Nguyen Dong , Khiem Nguyen Tien
Published: April 2018

The influence of the periodic force on the nonlinear first order systems with delay is investigated by the asymptotic method Crulov-Bogoliubov-Mitropolski. A detailed research of the response of Duffing and Van der Pol systems to external periodic force is given. The obtained results are compared with well-known ones in such second order systems without delay.
The absorber in self-excited system with random excitation
Authors: Anh Nguyen Dong , Duc Kieu The
Published: April 2018

In this paper, the absorber effect for self-excited system with random excitation is examined. It turns out that the random-self-oscillations can be suppressed by increasing the damping coefficient of the absorber. The results are obtained by averaging method and the FPK one.
Về một bài toán khuếch tán rối hợp chất
Authors: Cuc Tran Van
Published: April 2018

None
Một phương pháp tính độ tin cậy của hệ cơ học
Authors: Duong Le Nhu
Published: April 2018

None
Dynamic absorber for drilling instrument
Authors: Dao Nguyen Van
Published: April 2018

None
Nghiên cứu sự phát triển của vết nứt trong kết cấu do quá trình mỏi rỉ
Authors: Vinh Tran Huu
Published: April 2018

None
On the stability of conical shells in the theory of elastic-plastic deformation processes
Authors: Dung Dao Van
Published: April 2018

None
Dynamic absorber for elastic system of high order
Authors: Da Hoang Van , Hau Hoang Thi
Published: April 2018

None
Instability of the interface of two viscous fluids moving in a channel. Part II a. Nonlinear problem
Authors: Tran Tran Van
Published: April 2018

In this paper, the method of multiple scaling is used for obtaining the am-altitude evolution equations from the weakly nonlinear problem of hydrodynamic stability of concurrent flow of two viscous fluids in a channel It. is shown that in the case of stability the, interface may evolve to some finite amplitude with periodic steady state.
Về một giả thiết va chạm
Authors: Dinh Nguyen Van
Published: April 2018

None
Nonlinear stability of co-current flow of two viscous fluids in a channel
Authors: Tran Tran Van
Published: April 2018

None
Lower bound analysis of rigid – plastic cylindrical. Shells subjected to large deflections loading impulsively
Authors: Tinh Tran Ba
Published: April 2018

None
On a method for solving the reliability problem of the mechanical system
Authors: Pho Nguyen Van
Published: April 2018

In this paper the problem of reliability is formulated in stochastic programming forms and corresponding algorithms are given. In some ordinary conditions of moebanical system, stochastic programming problems can change by that ones or the deterministic mathematical programming.
Xác định tích phân J bằng phương pháp thực nghiệm để đánh giá khả năng nứt gãy của vật liệu và kết cấu
Authors: Vinh Tran Huu
Published: April 2018

None
Stationary solution of heat-mass transfer problem in porous media with volumetrical heat source
Authors: Hai Duong Ngoc
Published: April 2018

Process of electromagnetic heating and filtration of fluids in porous media with regard to mass transfer (melting or induration) is investigated. Theorem about existence and only stationary solution in dependence on geometrical characteristics of space, external heat action and thermal physical and electromagnetic characteristics of media has been proved. Regarded process is possibly used for drying and cleaning a porous media, for recovery and increased production of oils and etc.
Các công thức xác định đặc tính hình - động học ăn khớp bánh răng côn xoắn
Authors: Lap Pham Van , Bac Pham Van
Published: April 2018

None
Solution of the partial derivative equation with nonlinear boundary conditions
Authors: Da Hoang Van
Published: April 2018

In this paper, the asymptotic method has been used to construct the solution of the partial derivative equation with nonlinear conditions, describing vibration of the rectangular thin plate. It is shown that the physical nonlinearity of the boundary has influence on oscillational characteristics of systems.
Về chuyển động đối lưu nhiệt của chất lỏng có mặt thoáng
Authors: Can Ngo Huy
Published: April 2018

None
Sức bền mỏi của các phần tử kết cấu và chi tiết máy có tiết diện không tròn
Authors: Hiep Nguyen Trong , Phuc Phan Huu
Published: April 2018

None
Lực cản sóng của tàu hai thân chuyển động trên mặt nước yên tĩnh
Authors: Hung Hoang Xuan , Man Dang Tung
Published: April 2018

None
Bài toán va chạm của các hệ cơ học
Authors: Sanh Do
Published: April 2018

None
A new displacement bound technique for rigid plastic continua subjectet to strong dynamic loading at large deflections II.
Authors: The Vu Van , Tinh Tran Ba
Published: April 2018

The method developed in [ 1] is applied herein in order to obtain lower hound to large displacements of the hinge supported circular plate acted on by impulsively, uniformly distributed loading. The plate is made from rigid and perfectly plastic material which yields according to the yield condition shown in fig- 1· The lower bound (1.21) is obtained when the dynamically admissible displacement and velocity are chosen in separated variable form which is a scalar time function multiplied by a vector shape function of space variable (1.13). In the case when W, Ẇ * are chosen in form (1.22). [comparison of the obtained estimate Eq (1.24) with previous solution of the same problem [1], upper bound [2] and experimental date [3] are presented in fig. 2
Thu nhận hệ phương trình BOUSSINESQ và phương trình KORTEWEG - DE VRIES tổng quát mô tả sự lan truyền sóng trên sông có tính đến biến dạng đáy
Authors: Hung Le The , Hung Pham
Published: April 2018

None
Some moments is earthquake engineering
Authors: Lien Tran Van
Published: April 2018

None
Về bài toán điều khiển cực nhanh hệ con lắc
Authors: Dinh Nguyen Van
Published: April 2018

None
On the motion of a system with program constraints of inequality type
Authors: Sanh Do
Published: April 2018

None
On a theorem of shakedown theory
Authors: Pho Nguyen Van
Published: April 2018

None
Truyền sóng vuông góc với lớp trong môi trường vô hạn, phân lớp tuần hoàn nén được có biến dạng ban đầu thuần nhất
Authors: Vinh Pham Chi
Published: April 2018

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Dao động phi tuyến trong hệ cơ học không OTONOM có tần số riêng thay đổi ngẫu nhiên
Authors: Anh Nguyen Dong
Published: April 2018

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Doing the plane dynamic elasto-plastic problem by the method of elastic root
Authors: Bich Nguyen Dang
Published: April 2018

In this paper, the method of clastic root used to answer the plane dynamic elasto plastic problem, for the half of plane made by material according to the theory of small elasto-plastic deformation, on the boundary supporte1 degree loading of motion with over sound speed, root in the first -step given analytical form.
Cấu trúc toán học của các vật thể đàn hồi
Authors: J. Rychlewski
Published: April 2018

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Về chuyển động đối lưu nhiệt trong chất lỏng quay
Authors: Can Ngo Huy
Published: April 2018

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Optimum design of concrete structures
Authors: Nhac Bui Nguyen
Published: April 2018

One of the optimum design methods, concerned with the concrete structures, has just been presented. In order to obtain the optimum design, the solution of nonlinear mathematical programming problem has to be worked out. The amplification of the method was illustrated by a practical example.
Hệ phương trình biến phân theo biên độ - pha của chế độ cân bằng ở hệ thống số
Authors: Dinh Nguyen Van
Published: April 2018

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Oscillation of the rectangular thin plate when making mention of the creep of material
Authors: Da Hoang Van
Published: April 2018

In this work, the author have modeled and set up the equation of motion of the rectangular thin plate with regard to the creep of material in critical case. The asymptotic solution was constructed by means of method [3] for autonomous system. To illustrate the presented method a concrete example had been analyzed. It is seen that the physical character of the material decreases the amplitude of the oscillation as viscous friction.
An algorithm for one - dimensional tidal model of river networks
Authors: Dac Nguyen Tat
Published: April 2018

There has been a great number and variety of numerical techniques for one-dimensional tidal model of river networks, e.g. [1. 2], which base themselves on the integration of the Saint-Venant equation. [1] requires a complicated procedure in classification of branches and in computation of the recurrence coefficients. [2] has some advantage in comparison with [1] but the degree of the system of linear equation to be solved is quite great. This makes it [l] fit only for simple networks of river. In this report a modified algorithm for river networks is given. It is shown that there is only one recurrence relation to be used for all branches describing the networks the graph structure is formed. The algorithm is flexible for users. The theory presented in this report has been programmed in FORTRAN  IV and the resulting computer program has been tested on a part of Mekong river.
Sức bền mỏi của trục có lỗ ngang chịu uốn và xoắn
Authors: Hiep Nguyen Trong
Published: April 2018

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Phương trình vi phân ngẫu nhiên xtratonovich và ứng dụng trong lý thuyết dao động ngẫu nhiên
Authors: Khiem Nguyen Tien
Published: April 2018

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Về các hệ cơ học bảo toàn có chứa tọa độ ấn suy rộng
Authors: Anh Nguyen Dong
Published: April 2018

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Giải gần đúng một bài toán thẩm trong môi trường nhiều lớp bằng phương pháp trực
Authors: Luoc Ngo Van , Dat Vu Van
Published: April 2018

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Một phương pháp xác định ứng suất, biến dạng và ổn định của hệ thanh đàn nhớt
Authors: Anh Mai
Published: April 2018

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Bài toán liên hợp về dối lưu tự nhiên của chất lỏng phi Niu Tơn trong kênh thẳng đứng
Authors: Quang Vu Duy
Published: April 2018

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On the dynamic absorber for self- excited system
Authors: Dao Nguyen Van
Published: April 2018

In this article it is shown that not only the << relative >> friction between basic mass and absorber as proposed in [ 1-3 ] but the << absolute >> friction between absorber and foundation has decisive role in the extinguishing of self – excited oscillation of the basic mass.
Influence of the baroclinic effects on the structures of planetary boundary layer of the atmosphere
Authors: Quang Le Dinh
Published: April 2018

The influence of the baroclinic effects on the fundamental characters of the atmospheric boundary layer atmosphere is studied. The obvious difference between the structures of boundary layer of both baroclinic and barotropic cases is presented. Especially the baroclinic effect on the low latitude may not be neglected.
Generalizeo - diffusive theory of solid mixtures. II. Thermo - elastic compozite
Authors: Chanh Trương Minh
Published: April 2018

A theory of thermo-elastic compozite materials is proposed. It is based on the generalized- diffusive theory of mixture. The influence of viscous dissipation is included in the general treatment. The linear version of the constitutive equations in the absence of the viscosity is exhibited in, detail in the case of isotropic compozite.
One-dimensional model for the computation of unsteady salinity intrusion in a river
Authors: Diep Nguyen Van , Dac Nguyen Tat , Duyet Tran Ngoc
Published: April 2018

The study is concerned with the development of a predictive, on – dimensional. Mathematical model for the salinity intrusion in a river. This is accomplished by means of simultaneous weighted implicit finite difference solutions to the salt balance equation and to the continuity and momentum equation which definite the tidal motion. It is shown that the boundary condition on salinity at downstream can be specified by using one condition during the flood tide and another condition during the ebb-tide. The resulting mathematical model, as solved by a finite-difference numerical technique can be used in a predictive manner for transient condition of downstream, surface elevation and time-varying fresh water discharges at upstream.
Micro thermo - elastic homogeneous mixtures
Authors: Chanh Trương Minh
Published: April 2018

The present work is concerned with the construction of a linear theory of thermo - elasticity for micro - homogeneous solid mixtures. The constitutive equations of those solids are obtained and the thermodynamic restrictions are studied.
Some dynamical calculations of a transducer of two constact points type with two degrees of freedom
Authors: Hung Do Trong , Khang Nguyen Van , Sanh Do , Tho Banh Xuan , Tho Ho Dac
Published: April 2018

As it is known, in machine-building two methods are used for checking the size of manufacturing details: the method of active check and the method of passive check and in connection with this there are two checking remedies: that of active check and passive check Is discussed in this paper the dynamical calculation of a transducer of type of two constact points with two degrees of freedom. The obtained results have been used for calculating a transducer for the national ·program 52.01.
Analysis of orthogonal plates by the theory of equivalences
Authors: Yen Nguyen Manh
Published: April 2018

The Prineiple of the Theory of Equivalences is to replace the Solid Body by a Fictions body which is easier to calculale. Using an Equivalent Solid made up of Bars with Geometrical and mechanical properties, the Problem of the Orthogonal Plates is then replaced by a Problem of research of the internal force state in a structure Using method of deformation. The computer program intended for Minsk- 32 is segmented in two parts utilizing only internal Memory.
Dao động dừng của các hệ đàn nhớt dưới kích động ngẫu nhiên
Authors: Khiem Nguyen Tien
Published: April 2018

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The extraction of dissolved matter from porous materials
Authors: Chanh Trương Minh
Published: April 2018

The extraction of dissolved matter from monodispersive of porous spheres and polydispersive mixture of spheres having different radii are considered within the framework of the generalized - diffusive theory. The obtained solutions are generalized as the classical results and can be used to define the kinematic coefficients.
Phương pháp chuyển tiếp trên hệ tấm có sườn
Authors: Tan Bui Duc
Published: April 2018

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Effect of intermediate supports location on natural frequencies of multiple cracked continuous beams
Authors: Nam Do , Khiem Nguyen Tien , Toan Le Khanh , Thao Nguyen Thi , Lien Pham Thi Ba
Published: April 2018

The present paper deals with free vibration of multiple cracked continuous beams with intermediate rigid supports. A simplified method is proposed to obtain general solution of free vibration in cracked beam with intermediate supports that is then used for natural frequency analysis of the beam in dependence upon cracks and support locations. Numerical results show that the support location or ratio of span lengths in combination with cracks makes a significant effect on eigenfrequency spectrum of beam. The discovered effects of support locations on eigenfrequency spectrum of cracked continuous beam are useful for detecting not only cracks but also positions of vanishing deflection on the beam.
Boundary identification for an elastic solid partly immersed in a liquid
Authors: Ang Dang Dinh , Dung Nguyen , Trong Dang Duc
Published: April 2018

The authors consider a long elastic cylinder of constant section Ω partly immersed in a liquid of constant density. It is assumed that the body is in the state of plane strain and that Ω has a boundary consisting of two piecewise smooth arcs assumed to meet each other at two, and only two, points on a horizontal line. The upper arc Γ, which is exposed to air, is assumed known, while the lower arc ϒ, assumed to be totally immersed in a liquid of constant density, is unknown and is to be determined. Under the conditions that the displacements and surface stresses on a subarc of Γ are known and that the lower arc ϒ is subjected to a known constant hydrostatic pressure, the authors prove a uniqueness theorem and in the case of existence of a solution, show the existence of a sequence of regularized solutions converging to the exact solution.
Successive algorithm for construction of equation of motion of constrained mechanical systems
Authors: Phong Dinh Van
Published: April 2018

The article devotes to the construction of equations of motion of constrained mechanical systems. The constraint conditions are successively appended to the already defined systems. Therefore the algorithm is very flexible and allows studying the separate constraints more in detail. For illustration of consequent steps of the algorithm one simple example is shown.
On an one- and quasi-two dimensional linking hydraulic model for the complex river network-validation and application
Authors: Hanh Nguyen Van , Can Ngo Huy , Diep Nguyen Van
Published: April 2018

This paper describes an approach to construct an one- and quasi-two dimensional hydraulic model for the complex river network, including various hydraulic structures. The model is based on the numerical solution of the Saint-Venant equations for river branches, the continuity equation for storages, the equation for junction conditions of the confluences, tributaries, the equation for hydraulic structures between rivers and storage cells. Cross sections are modeled as a combination of main and flood plain parts to simulate better the flow pattern. The calculating program has been developed, validated by test cases, proposed by European big hydraulic research laboratories and then applied to build a hydraulic model for the complicated Red-Thai Binh river network.
Numerical simulation of pollutant dispersion near obstacle based on k - ɛ turbulence closure scheme
Authors: Hai Duong Ngoc , Duc Nguyen The
Published: April 2018

To simulate the wind field, pollutant transport and dispersion near an obstacle a numerical code based on the k - Ɛ turbulence model has been built. Beside the standerd k - Ɛ, two other modifications proposed by Detering & Etling and Duynkerke are also considered. The calculation results are verified based on the measurement data of von Karman Institute for Fluid Dynamics (Belgium). Modifications of the turbulent Schmidt number were carried out in order to match the measured results. The code was used to investigate the influence of the recirculation zone behind a building of cubical shape on the transport and disersion of pollutant. For a stack behind and near the obstacle, some conclusions about the effect of the stack height and stack location were derived.
Uniqueness of elastic continuation in a semilinear elastic body
Authors: Ang Dang Dinh , Dung Nguyen , Huy Nguyen Vu , Trong Dang Duc
Published: April 2018

The authors prove a theorem on uniqueness of elastic continuation in a nonhomogeneous elastic solid with a displacement-dependent tension modulus, generalizing an earlier result by Ang, Ikehata, Trong and Yamamoto for a nonhomogeneous linear elastic solid.
On a variant of the asymptotic procedure (for weakly nonlinear autonomous systems)
Authors: Dinh Nguyen Van
Published: April 2018

As well-known, usually, in the asymptotic (Krylov-Bogoliubov-Mitropolski) method, the full amplitude (a) of the first harmonic is used as variable in asymptotic expansions [1]. In the first approximation, the equations of stationary oscillations are rather simple, however, in higher approximation, these equations often become very complicated, especially when initial conditions are imposed.
Applying the contact element for simulation of interaction between drillstring and holewall
Authors: Hao Le Phuoc , Dung Ta Quoc
Published: April 2018

The purpose of research is to create a contact element in order to simulate the dynamics contact phenomenon of drillstring and drillhole. The contact element is located at some selected node along the drillstring. In the contact element, not only transverse friction force but also the longitudinal friction forces are taken into account. The element stiffness and damping matrices are derived explicitly. This element is implemented in general and powerful multi-body dynamics analysis software, namely Mecano module of Samcef. Therefore, many computational aspects of the Mecano software, for example the nonlinear beam element, the implicit time integration method, can be directly applied.
Connected oscillations in a nonlinearly coupled system
Authors: Dao Nguyen Van
Published: April 2018

A single-mass plane system subjected to symmetric restoring forces can strongly oscillate in the direction which is free from the external excitation. The raising oscillation is called the connected one. This phenomenon exists only in nonlinear systems under certain resonance conditions and was first investigated by Kononenko V. 0.
Synchronization in the second approximation
Authors: Dinh Nguyen Van
Published: April 2018

It is well-known the phenomenon of synchronization (frequency entrainment) in self-excited systems subjected to external or parametric excitations; A lot of monographs [2, 3, 4] has analyzed several important systems for which the synchronization effect occurs and can be determined in the first approximation. However, there exist also certain systems possessing a stable-excited oscillation obtained in the first approximation, which may be synchronized only in the second approximation. This article deals with some systems of the mentioned type; the asymptotic method [1] is applied for this purpose.