[en] Shape memory effect is the most effectively performed on NiTi shape memory alloy. The shape memory effect phenomena are related to solid-state phase transformation so the atomic neighbourhood orientation keeps during the phase transformation process. Stress and energy release during the phase transformation have effects on orientations of the atomic structure. However, if SMAs are exposure to repeated regular deforming and shape recovery cyclings, this will eventually cause some loses in their shape memory recoverability. In this study, the shape memory effect loss ratio of Ni_46.84Ti_53.16 (at%) alloy was investigated by systematic stress-strain mechanical tests and significant shifts was recorded on shape recovery ratios. (paper)

[en] Nowadays there is no viable non-destructive method that could detect flaws in complex composite products. Such a method could provide unique tools to allow engineers to minimize time consumption and cost during the evaluation of various product parameters without disturbing production. The latest research and development on propagation waves introduce micro, radio and millimetre waves as new potential non-destructive test methods for evaluation of mechanical flaws and prediction of failure in a product during production. This paper focuses on recent developments, usage, classification of electromagnetic waves under the range of radio frequency, millimetre and micro-waves. In addition, this paper reviews the application of propagation wave and proposed a new health monitoring technique based on Doppler Effect for vibration measurement in complex composite structures. Doppler Effect is influenced by dynamic behaviour of the composite structures and both are effect by flaws occurred inside the structure. Composite manufacturers, especially Aerospace industry are demanding these methods comprehensively inspect and evaluate the damages and defects in their products. (paper)

[en] Highlights: • The reliability metrics of the nonhomogeneous one-shot units are derived validated. • The operational use of the one-shot units is optimized under different scenarios. • Bounds of the optimal operational reliability are derived and verified. • A simulation model validated the derived reliability metrics of one-shot units. One-shot units are produced in batches and stored until use. While in storage, they are subjected to random non-destructive tests (NDTs) throughout their life horizon to determine their reliability metrics. Some of the one-shot units (with nonhomogeneous characteristics) are retrieved from storage and launched for operational use when needed. Referring to the launched units as a system, we optimize the system's operational use by determining the selected units’ characteristics and their launching order. The system reliability metrics are considered in the optimum selection and launching procedure. Considering the units’ inhomogeneity, we provide the confidence bounds of the probability that the system achieves a successful operation based on the optimal selection and launching order. A simulation model is developed to validate the proposed plan to optimize the units’ operational use.

[en] Inspired by the studies on defects in nondestructive monitoring techniques, we propose a new type of metasurface with single-groove array to manipulate Lamb waves in plate structures along arbitrary trajectories. Because of the interaction between the groove and the Lamb waves, the phase of a transmitted wave varies with the groove position. We manipulated a transmitted wave by optimizing the groove position on the metasurface and realized abnormal refraction, self-accelerating acoustic beams, and source illusion devices. The numerical results confirmed the broadband and robustness of the metasurface in terms of its wave manipulation capability, providing a basis for the design of wave control devices. The proposed method has potential applications in the fields of structural nondestructive testing, vibration control, and signal modulation. (paper)

[en] Numerical prediction of elastic characteristics of spatially reinforced composite materials (SRCM) with various reinforcement schemes is carried out in the work. Idealized SRCM structures constructed using TexGen, as well as parametrized geometric models constructed manually, are considered. It is revealed that, in spite of TexGen algorithms improved in recent times, it is impossible to achieve the required volume fraction of fibers corresponding to a real composite when constructing models of complex spatial structure of SRCM, and besides, self-intersection of weft and sewing threads often occurs. To eliminate the identified errors, idealized, parametrized geometric models in the language APDL were developed. In the framework of the developed geometric models, it was possible to realize a more dense arrangement of filaments in the frame, which allowed to maintain the percentage of the volume fraction of the reinforcing cage for the structures under consideration. The effective elastic characteristics of SRCM calculated using the developed numerical models and obtained as a result of mechanical tests were compared. (paper)

No abstract available

[en] In reliability theory, there is often a need to establish a relationship between parameters non-observed simultaneously. An example of such parameters is the operating time of the same product in different modes, because it’s impossible to experience the same product before destruction in several modes. In carrying out such destructive testing, the following question often arises: how to determine the operating time of a product in some specific, set mode, knowing the time of operation of this product in a different mode. By "mode" in this case a certain condition types for testing construction products are implied, for example, various climatic conditions, loads affecting the building construction, as well as other external influences in which the work of the product is possible. In practice, this problem is reduced to the investigation of the truth or falsity of the hypothesis that the operating time of the product in the first and second modes (ε ₁ and ε ₂) depends on some function (φ), chosen on the basis of a qualitative analysis of the problem. Since in real conditions when determining the reliability of products you often deal with samples of small size, in this paper we investigated the admissibility of applying the technique for calculating the reliability of building structures and products for small samples. The simulation results are shown in tables and are graphically depicted. (paper)

[en] The mechanical properties of viscoelastic materials are usually described by a rheological model composed of spring and dashpot in series or in parallel or their combination. The complex modulus as a function of angular frequency was firstly deduced, when fractional derivative rheological model is subjected to a sinusoidal perturbation in dynamic mechanical analysis (DMA) measurements. Then, the algebraic equations between the storage and loss moduli of the fractional Zener model in complex plane have been developed. The curve on the complex plane, a plot of loss modulus against storage modulus, is a repressed or distorted semicircle with its center below the real axis. The parameters of mechanical elements can be graphically estimated from its complex plane plot. The dynamic mechanical test of bituminous mixtures was carried out by frequency sweep over a wide range of 200 Hz to 0.02 Hz and its mechanical response can be described adequately by the fractional Zener model, whose element parameters are determined via geometric method. (paper)

[en] The authors conducted research to find methods of nondestructive testing for preliminary determination of detonation of thin-layer nanostructured explosives obtained by thermal vacuum sublimation. It was necessary for detecting the relationship between the microstructure and its detonation. It is shown that the specific length of crystals correlates with its detonation and can be used for nondestructive testing of thin-layer nanostructured explosives obtained by thermal vacuum sublimation

[en] Department of Electrical Engineering and Nondestructive Testing, NRU “MPEI”, has been working on development Electronic Learning Resources (ELRs) in course Electrical Engineering and Electronics for several years. This work have been focused on education intensification and effectiveness while training bachelors in nonelectrical specializations including students from Thermal and Atomic Power Engineering Institute. The developed ELRs are united in a tutorial module consisting of three parts (Electrical Circuits, Electrical Machines, Basics of Electronics): electronic textbook and workbook (ETW); virtual laboratory sessions (VLS); training sessions (ETS); personal tasks (PT); testing system that contains electronic tests in all course subjects and built-in verification of a student’s work results in ETW, VLS, ETS, PT. The report presents samples of different ELRs in html format and MathCAD, MatLAB Simulink applications, copyrighted programs in Java2, Delphi, VB6, C++. The report also contains the experience description, advantages and disadvantages of the new technologies. It is mentioned that ELRs provide new opportunities in course studying. (paper)