Лако-красочные материалы — производство

Fiber Bragg Gratings (FBGs) are becoming increasingly more popular for strain based SHM technique. A fiber Bragg grating is region of periodic refractive index modulation inscribed in the core of an optical fiber such that it diffracts the propagating optical signal at a specific wavelength. Bragg grating is written into a single mode optical fiber. […]

An electrical strain gauge mainly consists of a resistance grid of very fine wire or more commonly, metallic foil in a grid pattern, connectors (also called solder tabs) and an encapsulation layer. The grid pattern maximizes the amount of metallic wire or foil subject to strain in the parallel direction. The cross-sectional area of the […]

Backface strain (BFS) measurement is a technique that can be used for the in-situ monitoring for SHM of crack initiation and propagation in adhesively bonded composite joints. Zhang et al., [39] assessed the use of the BFS technique in bonded joints. Their work with single lap joint (SLJ) allowed for finding out that by detecting […]

Strain-based methods are effective SHM methods, because the presence of damage in the structure under operational loads can alter the local strain distribution due to the load path changing within the structure. Both electrical resistance strain gages as well as Fiber Bragg grating (FBG) optical sensors are usually used in the method to measure the […]

Active vibration-based monitoring method is a classical SHM technique. The main idea behind the method is that structural dynamic characteristics are functions of the physical properties, such as mass, stiffness and damping [22]. Hence, physical property changes due to damages can cause detectable differences in vibration responses. The dynamic characteristic parameters usually used in the […]

Amanda et al., [15] established a technique which holds promise for detecting damage and evaluating different failure modes in adhesively-bonded composite-to-metal single-lap shear joints. They compared electrical resistance data using carbon nanotubes in adhesive with AE and found good agreement. Carbon nanotubes (CNTs) have found many applications due to their high aspect ratio, high specific […]

Acoustic emission consists of a rapid release of energy as a material undergoes fracture or deformation. In SHM, two important features of acoustic emission are important: its ability to perform remote detection of crack formation or movement at the time it occurs and to do this continuously [12]. A schematic representation of acoustic emission (AE) […]

Structural Health Monitoring (SHM) can be defined as the method by which sensors are utilized to identify and quantify structural integrity through a continuous in-service monitoring process. In this manner, corrective maintenance can be performed when required before the structure reaches the critical point of catastrophic sudden failure. Even though adhesively bonded composite joints have […]

Composite materials as well as adhesively bonded joints are not exempt from some problems even though they have great advantages and applicability. Defects related to composite bonded joints can be classified into two main streams — manufacturing defects and in service defects. The source of manufacturing defects in a bonded composite joint can be due […]

Joint Definition and Configuration In adhesive bonding process, material, termed as substrate, is joined by placing and solidifying an adhesive between the adherend surfaces to produce an adhesive joint. It is also possible to join similar as well as dissimilar materials by adhesively bonded joint. Proper surface preparation must be taken care of the substrates […]