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Dmitri Mungalov

Bio: Dmitri Mungalov is an academic researcher from Latvian Academy of Sciences. The author has contributed to research in topics: Crimp & Composite number. The author has an hindex of 11, co-authored 29 publications receiving 585 citations.

Papers
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Journal ArticleDOI
TL;DR: In this article, a comparison of in-plane tensile properties of two single-ply non-crimp 3D orthogonal weave E-glass fiber composites on one side and a laminate reinforced with four plies of plain weave Eglass fabric on the other is presented.
Abstract: Composites fabricated by VARTM technology with the use of single-ply non-crimp 3D orthogonal woven preforms 3WEAVE ® find fast growing research interest and industrial applications. It is now well understood and appreciated that this type of advanced composites provides efficient delamination suppression, enhanced damage tolerance, and superior impact, ballistic and blast performance characteristics over 2D fabric laminates. At the same time, this type of composites, having practically straight in-plane fibers, show significantly better in-plane stiffness and strength properties than respective properties of a “conventional” type 3D interlock weave composites. One primarily important question, which has not been addressed yet, is how the in-plane elastic and strength characteristics of this type of composites compare with respective in-plane properties of “equivalent” laminates made of 2D woven fabrics. This 2-part paper presents a comprehensive experimental study of the comparison of in-plane tensile properties of two single-ply non-crimp 3D orthogonal weave E-glass fiber composites on one side and a laminate reinforced with four plies of plain weave E-glass fabric on the other. Results obtained from mechanical testing are supplemented by acoustic emission data providing damage initiation thresholds, progressive cracks observation, full-field surface strain mapping and cracks observation on micrographs. The obtained results demonstrate that the studied 3D non-crimp orthogonal woven composites have considerably higher in-plane ultimate failure stresses and strains, as well as damage initiation strain thresholds than their 2D woven laminated composite counterpart. Part 1 presents the description of materials used, experimental techniques applied, principal results and their mutual comparisons for the three tested composites. Part 2 describes in detail the experimentally observed effects and trends with the main focus on the progressive damage: detailed results of AE registration, full-field strain measurements and progressive damage observations, highlighting peculiarities of local damage patterns and explaining the succession of local damage events, which leads to the differences in strength values between 2D and 3D composites.

187 citations

Journal ArticleDOI
TL;DR: In this article, the internal geometry of a carbon fiber non-crimp 3D orthogonal woven composite is presented, including: waviness of yarns, cross sections of the yarn, dimensions of yarn cross sections, and local fiber volume fraction.
Abstract: Measurements of the internal geometry of a carbon fiber non-crimp 3D orthogonal woven composite are presented, including: waviness of the yarns, cross sections of the yarns, dimensions of the yarn cross sections, and local fiber volume fraction. The measured waviness of warp and fill yarns are well below 0.1%, which shows that the fabric termed here “non-crimp” has nearly straight in-plane fibers as-produced, and this feature is maintained after going through all steps of fabric handling and composite manufacturing. The variability of dimensions of the yarns is in the range of 4–8% for warp and fill directions, while the variability of the yarn spacing is in the range of 3–4%. These variability parameters are lower than respective ranges of variability of the yarn waviness and the cross-sectional dimensions in typical carbon 2D weave and 3D interlock weave composites, which are also illustrated in this work for comparison.

126 citations

Journal ArticleDOI
TL;DR: In this article, tension-tension fatigue behavior of a single-ply non-crimp 3D orthogonal weave E-glass composite and of a laminated composite reinforced with four plies of a standard plain weave fabric was studied.

77 citations

Patent
28 Nov 2001
TL;DR: In this paper, a machine for producing complex-shaped, three-dimensional engineered fiber preforms having unitary, integral and seamless structures, a method for making the preforms on the machine, and reforms produced thereby.
Abstract: A machine for producing complex-shaped, three-dimensional engineered fiber preforms having unitary, integral and seamless structures, a method for making the preforms on the machine, and reforms produced thereby. The integral design and structure of the preform is formed by a combination of interlacing and non-interlacing fiber systems (12) that permits variable cross-sectional area and dimensions from a first end to a second end along an axis via selective activation and control (11) of at least one module (3), preferably a plurality of module connected to each other in any desirable configuration.

35 citations

Patent
19 Sep 2001
TL;DR: In this article, an integral design of a carbon - carbon composite valve (VII) structure for engines of internal combustion, formed by set of straight and interlacing continuous reinforcing yarns with the help of the device with the combined mechanical scheme, allowing to produce various types of axis-symmetric braiding architectures, including, but not limited to cylindrical, conical, and radial yarn placement to make an integral valve with continuously variable reinforcement architecture at various zones of the valve.
Abstract: A three-dimensional engineered fiber preform having a unitary, integral and seamless structure and rigid composite structure made therefrom for use as a mechanical component, particularly for use as a valve, and method for making the preform. The integral design and structure area and dimensions from a first end to a second end along an axis, or from a stem end to a head end of a valve. A particular embodiment of the invention is an integral design of a carbon - carbon composite valve (VII) structure for engines of internal combustion, formed by set of straight and interlacing continuous reinforcing yarns (I) with the help of the device with the combined mechanical scheme, allowing to produce various types of axis-symmetric braiding architectures, including, but not limited to cylindrical, conical, and radial yarn placement to make an integral valve with continuously variable reinforcement architecture at various zones of the valve.

24 citations


Cited by
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Journal ArticleDOI
TL;DR: A critical review is presented on the current state of the arts of wearable fiber/fabric-based piezoelectric nanogenerators and triboelectrics with respect to basic classifications, material selections, fabrication techniques, structural designs, and working principles, as well as potential applications.
Abstract: Integration of advanced nanogenerator technology with conventional textile processes fosters the emergence of textile-based nanogenerators (NGs), which will inevitably promote the rapid development and widespread applications of next-generation wearable electronics and multifaceted artificial intelligence systems. NGs endow smart textiles with mechanical energy harvesting and multifunctional self-powered sensing capabilities, while textiles provide a versatile flexible design carrier and extensive wearable application platform for their development. However, due to the lack of an effective interactive platform and communication channel between researchers specializing in NGs and those good at textiles, it is rather difficult to achieve fiber/fabric-based NGs with both excellent electrical output properties and outstanding textile-related performances. To this end, a critical review is presented on the current state of the arts of wearable fiber/fabric-based piezoelectric nanogenerators and triboelectric nanogenerators with respect to basic classifications, material selections, fabrication techniques, structural designs, and working principles, as well as potential applications. Furthermore, the potential difficulties and tough challenges that can impede their large-scale commercial applications are summarized and discussed. It is hoped that this review will not only deepen the ties between smart textiles and wearable NGs, but also push forward further research and applications of future wearable fiber/fabric-based NGs.

729 citations

Journal ArticleDOI
TL;DR: In this paper, the authors examined the recent advancements in the science and technology of carbon nanotube (CNT)-based fibers and composites, and made an assessment according to the hierarchical structural levels of CNTs used in composites.

543 citations

Patent
23 Dec 2008
TL;DR: In this paper, a system for assisting in a surgical process is described, consisting of a surgical tool and a surgical implant, a positional sensor carried by the surgical device, and a computer system including a wireless receiver and signal conditioning circuitry and hardware for converting sensor data received by the wireless receiver into at least one of (i) audio feedback of positional information for the surgical devices and (ii) visual feedback for the devices.
Abstract: A system for assisting in a surgical process, comprising: (a) a surgical device taken from a group consisting of a surgical tool and a surgical implant; (b) a positional sensor carried by the surgical device, the positional sensor including a wireless transmitter and associated circuitry for transmitting sensor data from the transmitter; and (c) a computer system including a wireless receiver and signal conditioning circuitry and hardware for converting sensor data received by the wireless receiver into at least one of (i) audio feedback of positional information for the surgical device and (ii) visual feedback of positional information for the surgical device.

257 citations

Journal ArticleDOI
TL;DR: In this article, the authors report the latest advances in this area, addressing the applications of advanced composites in ships and ship components, offshore oil and gas composites, marine renewable energy and underwater repairing.
Abstract: Components and structures working in the marine environment are exposed to high stresses attributable to the action of wind, waves, and tides. Moreover, they have to face hostile and severe environmental conditions during their lifetime, being placed in the splash zone if not even submerged in saltwater. The application of polymer composites in marine systems has been the focus of intensive studies in the last decades, highlighting potential benefits given by the replacement of several components, such as ship hulls, propeller blades, wind, and tidal turbine blades, to cite but a few. The present paper reports the latest advances in this area, addressing the applications of advanced composites in ships and ship components, offshore oil and gas composites, marine renewable energy and underwater repairing.

221 citations

Journal ArticleDOI
TL;DR: In this article, the voxel method and a continuum damage model are used in a finite element analysis to compute stress-strain curves for an orthogonal 3D woven composite under tensile loading.

208 citations