Статті в журналах: "Dynamic composites"

1

Xu, Shan Qing, Dong Ruan, Jason Miller, Igor Sbarski, and Ajay Kapoor. "Dynamic Response of Polymer Based Shear Stiffening Composite." Key Engineering Materials 626 (August 2014): 323–28. http://dx.doi.org/10.4028/www.scientific.net/kem.626.323.

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In this paper, the uniaxial dynamic compressive response and rheological properties of a newly developed commercially available polymer based shear stiffening (PSS) composite is experimentally studied at different crushing velocities. The results showed that the compressive stress of PSS composites increases with the rising strain rates. Comparing the stress-strain curves of PSS composites and neoprene at the same strain rate, it was found that the compressive stress of PSS composite increased gradually with strain, while the compressive stress of neoprene increased sharply with strain. The uniaxial dynamic mechanical analyses of PSS composites showed that storage modulus of PSS composite increased with the increase of sweep frequency. The rheological study of PSS composites showed that the storage modulus of PSS composite significantly increased when the angular frequency was higher than a critical value, e.g., 100 rad/s, demonstrating evident shear stiffening properties.

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2

Idriss, M., and A. El Mahi. "Dynamic characteristics of sandwich composite with debonding." Journal of Thermoplastic Composite Materials 32, no. 9 (August 27, 2018): 1204–23. http://dx.doi.org/10.1177/0892705718797162.

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The article presents the results of experimental and finite element analyses of the flexural vibration behavior sandwich composite with different debonding ratios. Sandwich composite consists of two thin skins composed of E-glass fiber and epoxy resin bonded to lightweight and weaker core material of PVC foams. Experimental tests using the impulse technique were performed on the sandwich constituents and sandwich composites with different debonding lengths. The modal dynamic characteristics of sandwich composite were measured and discussed for each debonding ratio. A finite element modeling was used to determine the natural frequencies, modal shapes, and stress and strain fields for each element of sandwich composites for each debonding ratio. The modal strain energy approach was used to determine the contribution of energies dissipated of the core and the skins in the total dissipated energy and the global damping of the different sandwich composites. The results obtained by this approach are compared with those obtained experimentally.

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3

Li, Yi, Youwei Zhang, Haiwei Dong, Wenjie Cheng, Chaoming Shi, and Jiangying Chen. "Dynamic Response of Electro-Mechanical Properties of Cement-Based Piezoelectric Composites." Applied Sciences 11, no. 24 (December 15, 2021): 11925. http://dx.doi.org/10.3390/app112411925.

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By employing ordinary Portland cement as a matrix and PZT-5H piezoelectric ceramic as the functional body, 1-3 and 2-2 cement-based piezoelectric composites were prepared. Quasi-static compression tests were performed along with dynamic impact loading tests to study the electro-mechanical response characteristics of 1-3 and 2-2 cement-based piezoelectric composites. The research results show that both composites exhibit strain rate effects under quasi-static compression and dynamic impact loading since they are strain-rate sensitive materials. The sensitivity of the two composites has a non-linear mutation point: in the quasi-static state, the sensitivity of 1-3 and 2-2 composites is 157 and 169 pC/N, respectively; in the dynamic state, the respective sensitivity is 323 and 296 pC/N. Although the sensitivity difference is not significant, the linear range of the 2-2 composite is 24.8% and 61.3% larger than that of the 1-3 composite under quasi-static compression and dynamic impact loading, respectively. Accordingly, the 2-2 composite exhibits certain advantages as a sensor material, irrespective of whether it is subjected to quasi-static or dynamic loading.

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4

Ismail Topcu, Ismail Topcu, Burcu Nilg n. etiner Burcu Nilg n etiner, and Arif N. G. ll o. lu and zkan G. lsoy Arif N G ll o lu and zkan G lsoy. "Investigation of Creep Behavior of CNT Reinforced Ti6Al4V Under Dynamic Loads." Journal of the chemical society of pakistan 42, no. 1 (2020): 70. http://dx.doi.org/10.52568/000618.

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This study investigates the effects of addition of Carbon nanotube (CNT) at different volume ratios (0.5- 5%) into Ti6Al4V matrix by mechanical alloying in terms of the density, microstructure, hardness and creep under dynamic load. As a result of the good bonding of carbon nanotubes powders with the main matrix, Ti-6Al-4V/CNT composites have experienced change both in microstructure and mechanical properties (such as hardness, density) and, correspondingly, qualitatively creep behaviour of Ti-6Al - 4V matrix alloy has been improved compared to the lean one. The density of CNT reinforced Ti6Al4V composites sintered at 1300and#176;C for 3h decreases with increasing CNT content. The hardness tests indicated that the hardness of composites increased with CNT addition. In addition, although creep strain is decreased continually with CNT content until 5%, creep life increased with increasing CNT content until 4% of CNT but decreased above 4%. After sintering at 1300 and#176;C under vacuum for 3 hours the density of the composite material reached to a level of 98.5 %, the microhardness to 538 HV and the creep behaviour was improved. The characterization of Ti6Al4V / CNT composites after mechanical alloying was carried out using scanning electron microscopy (SEM), energy dispersive x-rays spectroscopy (EDS) analysis and X-ray diffraction (XRD) methods. Although Ti–6Al–4V alloys are used as biomaterial, this study aimed at using MWCNTs containing Ti-6Al-4V composites at high temperature applications. Because MWCNTs reinforced Ti-6Al-4V composites are cheaper and have lower weight than the other materials used in this kind of applications.

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5

Ismail Topcu, Ismail Topcu, Burcu Nilg n. etiner Burcu Nilg n etiner, and Arif N. G. ll o. lu and zkan G. lsoy Arif N G ll o lu and zkan G lsoy. "Investigation of Creep Behavior of CNT Reinforced Ti6Al4V Under Dynamic Loads." Journal of the chemical society of pakistan 42, no. 1 (2020): 70. http://dx.doi.org/10.52568/000618/jcsp/42.01.2020.

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This study investigates the effects of addition of Carbon nanotube (CNT) at different volume ratios (0.5- 5%) into Ti6Al4V matrix by mechanical alloying in terms of the density, microstructure, hardness and creep under dynamic load. As a result of the good bonding of carbon nanotubes powders with the main matrix, Ti-6Al-4V/CNT composites have experienced change both in microstructure and mechanical properties (such as hardness, density) and, correspondingly, qualitatively creep behaviour of Ti-6Al - 4V matrix alloy has been improved compared to the lean one. The density of CNT reinforced Ti6Al4V composites sintered at 1300and#176;C for 3h decreases with increasing CNT content. The hardness tests indicated that the hardness of composites increased with CNT addition. In addition, although creep strain is decreased continually with CNT content until 5%, creep life increased with increasing CNT content until 4% of CNT but decreased above 4%. After sintering at 1300 and#176;C under vacuum for 3 hours the density of the composite material reached to a level of 98.5 %, the microhardness to 538 HV and the creep behaviour was improved. The characterization of Ti6Al4V / CNT composites after mechanical alloying was carried out using scanning electron microscopy (SEM), energy dispersive x-rays spectroscopy (EDS) analysis and X-ray diffraction (XRD) methods. Although Ti–6Al–4V alloys are used as biomaterial, this study aimed at using MWCNTs containing Ti-6Al-4V composites at high temperature applications. Because MWCNTs reinforced Ti-6Al-4V composites are cheaper and have lower weight than the other materials used in this kind of applications.

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6

Srivastava, V. K. "Dynamic Fracture Toughness Behaviour of CFRP-Foam-CFRP Sandwich Composite and Particles Filled Hybrid Glass Fiber Cloth, Graphene Nanoplates Coated Glass Fiber Strand Composite Materials under Low Impact Velocity." Journal of Materials Science Research 11, no. 1 (May 23, 2022): 70. http://dx.doi.org/10.5539/jmsr.v11n1p70.

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The main objective of the present study is to investigate the dynamic fracture toughness behaviors of CFRP-Foam-CFRP sandwich composite of V-notched through -thickness, surface, and un-notched specimens under Izod, and Charpy impact tests.  The sandwich composite structures are made of cross-plied carbon fiber reinforced plastic (CFRP) composite faces with polyurethane foam core. CFRP composites are used to combine the upper face and the lower face through the core in stitched sandwich structures. Compressive strength of weight drop impact perforated and un-perforated sandwich composite specimens are measured from a universal testing machine. Also, particles (Al2O3, CNTs, and cement) filled glass fiber cloth and graphene nanoplates coated glass fiber strands reinforced polymer hybrid composite are fabricated for V-notched, un-notched Izod impact and Charpy impact tests. The results show that weight drop impact energy is lower than the Izod impact energy but higher than the Charpy impact energy, whereas the dynamic fracture toughness of Izod impact energy is more than the Charpy and weight drop impact energy due to geometry of impactor and sandwich specimen. However energy and dynamic fracture toughness of Al2O3, CNTs, and Cement filled un-notched hybrid composites higher than the notched hybrid composites under Izod Impact. The dynamic fracture toughness and energy of CNTs filled hybrid composites is higher than the sandwich composites, Al2O3, and Cement filled hybrid composites under Charpy Impact.

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7

Anjum, Q., N. Nasir, S. A. Cheema, M. Imran, A. R. Rahman, Z. Tanveer, N. Amin, and Y. N. Anjam. "Multiscale modeling investigation into the thermal conductivity dynamics of graphene-silver nano-composites: a molecular dynamic study." Digest Journal of Nanomaterials and Biostructures 17, no. 2 (April 2022): 557–68. http://dx.doi.org/10.15251/djnb.2022.172.557.

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This research primarily aims at the in-depth exploration of thermal conductivity dynamics of Graphene-Silver (C-Ag) nano-composites on various parametric fronts. The parametric settings and resultant experimental states are mimicked by the rigorous launch of molecular dynamic (MD) simulations with Green-Kubo multiscale modeling approach. The enumeration of thermal conductivity of C-Ag nano-composites is instigated along with three orientations that is C-Ag (1 0 0), C-Ag (1 1 0) and C-Ag (1 1 1). Further, the conductive subtleties are expounded with respect to numerous factors of practical concerns such as, temperature, length of composite, composite width and number of Ag layers.

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8

Bourne, N. K., S. Parry, D. Townsend, P. J. Withers, C. Soutis, and C. Frias. "Dynamic damage in carbon-fibre composites." Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 374, no. 2071 (July 13, 2016): 20160018. http://dx.doi.org/10.1098/rsta.2016.0018.

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The Taylor test is used to determine damage evolution in carbon-fibre composites across a range of strain rates. The hierarchy of damage across the scales is key in determining the suite of operating mechanisms and high-speed diagnostics are used to determine states during dynamic loading. Experiments record the test response as a function of the orientation of the cylinder cut from the engineered multi-ply composite with high-speed photography and post-mortem target examination. The ensuing damage occurs during the shock compression phase but three other tensile loading modes operate during the test and these are explored. Experiment has shown that ply orientations respond to two components of release; longitudinal and radial as well as the hoop stresses generated in inelastic flow at the impact surface. The test is a discriminant not only of damage thresholds but of local failure modes and their kinetics. This article is part of the themed issue ‘Multiscale modelling of the structural integrity of composite materials’.

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9

Monte Vidal, Dielly Cavalcanti da Silva, Heitor L. Ornaghi, Felipe Gustavo Ornaghi, Francisco Maciel Monticeli, Herman Jacobus Cornelis Voorwald, and Maria Odila Hilário Cioffi. "Effect of different stacking sequences on hybrid carbon/glass/epoxy composites laminate: Thermal, dynamic mechanical and long-term behavior." Journal of Composite Materials 54, no. 6 (August 6, 2019): 731–43. http://dx.doi.org/10.1177/0021998319868512.

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In the present study, different stacking sequences on hybrid carbon/glass/epoxy composites laminate were examined in relation to thermal, dynamic mechanical and long-term behavior. A positive hybrid effect was found for both hybrid composites (interleaved-Hybrid 1 and in block-Hybrid 2) showing that in some cases hybrid composites can properly replace carbon or glass composites. The composite containing all glass fiber in the middle (Hybrid 2) presented similar thermal behavior when compared to glass fiber composite. All hybrid composites presented higher storage modulus when compared to glass composite. Dynamic mechanical analysis showed that both hybrids can satisfactorily perform the requirement in a wide temperature range. The long-term prediction was successfully applied for all composites, showing to be highly temperature-dependent. Hence, depending on the application requirement, both hybrids can be used, saving weight and cost.

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10

Wang, Liang, Rui-Xiang Bai, and Hao-Ran Chen. "Finite Element Analysis for Interfacial Crack in Piezoelectric Composite under Impact Loading." Advanced Composites Letters 21, no. 1 (January 2012): 096369351202100. http://dx.doi.org/10.1177/096369351202100103.

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In this paper, a nonlinear finite element analysis of impact interfacial fracture for a piezoelectric composite is provided. The Newmark method was used to solve the dynamics equation. Virtual crack closure technique is to evaluate the energy release rate of crack tip. Contact elements were set up on crack surface and in the area in contact under impact loading to prevent the penetration between PZT and composite. The response curves of the energy release rate are obtained for piezoelectric composites. Numerical results are provided to show the effect of the piezoelectricity, the applied voltage, the stack sequence of composites and the contact of crack surface on the resulting dynamic energy release rate of piezoelectric composites.

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11

Sierakowski, R. L. "Strain Rate Effects in Composites." Applied Mechanics Reviews 50, no. 12 (December 1, 1997): 741–61. http://dx.doi.org/10.1115/1.3101860.

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A review of the high strain rate behavior of filamentary composite materials is presented. The experimental techniques used for evaluating the dynamic performance of composites are discussed, as well as results obtained by researchers for various types of filamentary composites. Areas of research needed for expanding the information base for composites as well as the testing devices needed to obtain composite test data are chronicled. This review article contains 120 references.

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12

Lamy, B., and E. Dixneuf. "Damage Tolerance of Composite Materials Subject to Dynamic Flexural Tests." Advanced Composites Letters 9, no. 1 (January 2000): 096369350000900. http://dx.doi.org/10.1177/096369350000900107.

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Experiments were conducted in order to study damage process generated on particular composite materials by low energy impacts. Woven and knitted reinforcement- structures were tested using a Charpy test. Experimental laws and analytical models characterising the damage evolution in these composite materials subjected to successive impacts are proposed and compared. Damage processes are different in both composites. The rupture of the woven composites is controlled by crackings and delaminations, the latter does not occur in the knitted ones. These analyses emphasise the interest of using knitted reinforcements in composite materials.

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13

He, Xun Lai, Jun Hui Yin, Zhen Qian Yang, and Hong Wei Liu. "Damage Mechanism Analysis of Carbon Fiber Composites under Compressive Load." Key Engineering Materials 775 (August 2018): 36–42. http://dx.doi.org/10.4028/www.scientific.net/kem.775.36.

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Carbon fiber composite material with light weight, high strength, corrosion resistance and other characteristics of its impact damage mechanism is different from the traditional metal materials. In this paper, the quasi-static compression of carbon fiber composites was carried out by using a material testing machine to analyze the damage mechanism. The Hopkinson bar technology was used to test the dynamic mechanical properties. The damage mechanism of the carbon fiber composites under dynamic compressive loading was studied. Stress - Strain relationship of composites under Quasi - static and dynamic compressive load. It is found that the main failure mode of out-of-plane direction of carbon fiber composite laminates is brittle shear failure, while the in-plane failure mode shows the properties of brittle materials.

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14

Sukhyy, Kostyantyn, Elena Belyanovskaya, Alla Nosova, Irina Sukha, Mikhailo Sukhyy, Yudong Huang, Yuriy Kochergin, and Tetiana Hryhorenko. "Dynamic Mechanical Properties of Epoxy Composites Modified with Polysulphide Rubber." Chemistry & Chemical Technology 16, no. 3 (September 30, 2022): 432–39. http://dx.doi.org/10.23939/chcht16.03.432.

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15

Dong, Biqin, Feng Xing, and Zongjin Li. "Electrical Response of Cement-Based Piezoelectric Ceramic Composites under Mechanical Loadings." Smart Materials Research 2011 (March 28, 2011): 1–7. http://dx.doi.org/10.1155/2011/236719.

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Electrical responses of cement-based piezoelectric ceramic composites under mechanical loadings are studied. A simple high order model is presented to explain the nonlinear phenomena, which is found in the electrical response of the composites under large mechanical loadings. For general situation, this nonlinear piezoelectric effect is quite small, and the composite is suitable for dynamic mechanical sensor as holding high static stability. The experimental results are consistent with the relationship quite well. The study shows that cement-based piezoelectric composite is suitable for potential application as dynamic mechanical sensor with excellent dynamic response and high static stability.

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16

Harshavardhan, B., R. Ravishankar, Bheemappa Suresha, and S. Srinivas. "Static and Dynamic Mechanical Performance of Carbon Fiber Reinforced Polyethersulfone Composites." Applied Mechanics and Materials 895 (November 2019): 265–71. http://dx.doi.org/10.4028/www.scientific.net/amm.895.265.

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This study has been carried out to demonstrate the effect of short carbon fiber (SCF) loading on static and dynamic mechanical performance of polyethersulfone (PES) composites. Different combinations of SCF/PES composites were prepared by extrusion followed by injection molding. The static mechanical properties such as hardness, tensile and flexural properties of PES based composites were analyzed following ISO standards. As engineering materials, the polymer composites with high modulus as well as excellent damping properties are of great interest in aerospace and automotive industries for severe dynamic environment. Furthermore, in addition to static properties of composites, dynamic mechanical behaviour of PES based composites was evaluated. Mechanical test results showed that increasing the SCF wt. % in the composites increases the hardness, tensile and flexural properties. Furthermore, the optimal SCF loading was found to be 30 wt. % for significantly improving the overall composite mechanical performance. Upon the reinforcing of SCFs, an improvement in the storage modulus was found. Based on the fractographic analysis, orientation and aligned structure of carbon fibers, good bonding of fibers within the matrix and better fiber-matrix interaction were the primary reasons leading to the improvement of mechanical properties. The optimized composite (PES with 30 wt. % of SCF) could be used in automotive components like frames, flap covers and gears of printing machinery.

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17

Yao, Yun Xiu, Yan Ting Sun, En Li Chen, and Bo Gang Chu. "Dynamic Characteristics of Carbon Nanotube Reinforced Epoxy Resin Composite Materials." Applied Mechanics and Materials 584-586 (July 2014): 1400–1406. http://dx.doi.org/10.4028/www.scientific.net/amm.584-586.1400.

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Carbon nanotubes (CNTs) were modified by alkali, and carbon nanotubes epoxy composites samples were prepared by the hot pressing method. Dynamic characteristics of the composites were studied by experiments. The results suggest that carbon nanotubes can hardly enhance the first natural frequency of epoxy composite, but the change of second and third order natural frequencies are obvious compared with the first one. Damping properties of the composites are improved, and with the mass ratio of CNTs increasing, the first three order damping properties of composites are all increased initially followed by the decrease. The results also indicate that flexural elastic modulus of the composites is enhanced, the first and the second order dynamic elastic modulus is greater than it but the third order is opposite. The first three order dynamic modulus of elasticity moments of CNTs composites whose mass fraction is two percent are all high.

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18

Cheng, Lin, Xiang Zhang, and Yu Bao Li. "Study on Dynamic Mechanical Properties of n-HA/PA66 Composites." Advanced Materials Research 418-420 (December 2011): 1511–15. http://dx.doi.org/10.4028/www.scientific.net/amr.418-420.1511.

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The dynamic mechanical properties of nano-hydroxyapatite (n-HA) reinforced polyamide 66 (PA66) biocomposites were studied with reference to the effect of n-HA content, frequency and physiological saline. The intrinsic properties of the components, morphology of the system and the nature of interface between the phases determine the dynamic mechanical properties of the composite. The storage modulus (E') values of n-HA/PA66 composites were much higher than those of pure PA66, indicating that the incorporation of n-HA in PA66 matrix induced reinforcing effects obviously. And the E' values of composites increased with increasing of n-HA content. The loss modulus (E") of the composite with 30wt% n-HA was higher that those of pure PA66 and the composite with 40wt% n-HA below 55°C, however, above 55°C, the E" values enhanced with increase of n-HA content. Both frequency and physiological saline had obvious effects on the dynamic mechanical properties for n-HA/PA66 composite. E' and E" values enhanced with increase of frequency, but tanδ values decreased with increasing of frequency. After soaked in physiological saline, the E' and E" values of the composite decreased.

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19

Selyutina, Nina, and Yuri Petrov. "Structural-Temporal Peculiarities of Dynamic Deformation of Layered Materials." Materials 15, no. 12 (June 16, 2022): 4271. http://dx.doi.org/10.3390/ma15124271.

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The temporal nature of static and dynamic deformation of fibre metal laminates is discussed here. The aim of the study is to verify the proposed innovate model using layered composites. The modified relaxation model is based on the earlier formulated plasticity relaxation model for homogeneous materials. The proposed relaxation model makes it possible to describe the deformation of the layered composites from elastic to irreversible deformation, finalised by the failure moment. The developed approach allows us to consider the effects of the transition from static to dynamic loading. This means that the model-calculated dynamic limiting characteristics of the metal and the strength of brittle materials will have a determining character, depending on the loading history. The verification of the model using a glass fibre reinforced aluminium composite, glass fibre reinforced titanium composite, carbon fibre reinforced aluminium composite, and Kevlar fibre reinforced aluminium composite with different thickness ratios between metal and polymer layers is given. It is shown that the theoretical deformation curves of the metal composites at the various strain rates, finalised by brittle fracture of the polymer layers or continued irreversible deformation of remaining unbroken metal layers with destroyed polymer (fibre/epoxy) layers, are predicted. Based on the same structural−temporal parameters for five (Ti/GFRP (0/90)/Ti/GFRP(90/0)/Ti) and three (Ti/GFRP(0/90/90/0)/Ti) layers glass fibre reinforced titanium composites and the polymer layers, one-stage and two-stage stress drops during the irreversible deformation of the composite under static and dynamic loading are simulated. The change of the multi-stage fracture of the composite from static to dynamic loading and the fracture characteristic times of the polymer (100 s and 15,400 s) and the metal (8.4 ms) are correlated. Continued plastic deformation of the composite after fracture of the polymer layers is related with different values of the characteristic relaxation times of the polymer (fibre/epoxy) and the metal layers.

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20

Shelef, Yaniv, Avihai Yosef Uzan, Ofer Braunshtein, and Benny Bar-On. "Assessing the Interfacial Dynamic Modulus of Biological Composites." Materials 14, no. 12 (June 21, 2021): 3428. http://dx.doi.org/10.3390/ma14123428.

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Biological composites (biocomposites) possess ultra-thin, irregular-shaped, energy dissipating interfacial regions that grant them crucial mechanical capabilities. Identifying the dynamic (viscoelastic) modulus of these interfacial regions is considered to be the key toward understanding the underlying structure–function relationships in various load-bearing biological materials including mollusk shells, arthropod cuticles, and plant parts. However, due to the submicron dimensions and the confined locations of these interfacial regions within the biocomposite, assessing their mechanical characteristics directly with experiments is nearly impossible. Here, we employ composite-mechanics modeling, analytical formulations, and numerical simulations to establish a theoretical framework that links the interfacial dynamic modulus of a biocomposite to the extrinsic characteristics of a larger-scale biocomposite segment. Accordingly, we introduce a methodology that enables back-calculating (via simple linear scaling) of the interfacial dynamic modulus of biocomposites from their far-field dynamic mechanical analysis. We demonstrate its usage on zigzag-shaped interfaces that are abundant in biocomposites. Our theoretical framework and methodological approach are applicable to the vast range of biocomposites in natural materials; its essence can be directly employed or generally adapted into analogous composite systems, such as architected nanocomposites, biomedical composites, and bioinspired materials.

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21

Breunig, P., V. Damodaran, K. Shahapurkar, S. Waddar, M. Doddamani, P. Jeyaraj, and P. Prabhakar. "Dynamic impact behavior of syntactic foam core sandwich composites." Journal of Composite Materials 54, no. 4 (November 10, 2019): 535–47. http://dx.doi.org/10.1177/0021998319885000.

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Sandwich composites and syntactic foams independently have been used in many engineering applications. However, there has been minimal effort towards taking advantage of the weight saving ability of syntactic foams in the cores of sandwich composites, especially with respect to the impact response of structures. To that end, the goal of this study is to investigate the mechanical response and damage mechanisms associated with syntactic foam core sandwich composites subjected to dynamic impact loading. In particular, this study investigates the influence of varying cenosphere volume fraction in syntactic foam core sandwich composites subjected to varying dynamic impact loading and further elucidates the extent and diversity of corresponding damage mechanisms. The syntactic foam cores are first fabricated using epoxy resin as the matrix and cenospheres as the reinforcement with four cenosphere volume fractions of 0% (pure epoxy), 20%, 40%, and 60%. The sandwich composite panels are then manufactured using the vacuum assisted resin transfer molding process with carbon fiber/vinyl ester facesheets. Dynamic impact tests are performed on the sandwich composite specimens at two energy levels of 80 J and 160 J, upon which the data are post-processed to gain a quantitative understanding of the impact response and damage mechanisms incurred by the specimens. A qualitative understanding is obtained through micro-computed tomography scanning of the impacted specimens. In addition, a finite element model is developed to investigate the causes for different damage mechanisms observed in specimens with different volume fractions.

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22

Scarpini Cândido, Verônica, Michel Picanço Oliveira, and Sergio Neves Monteiro. "Dynamic-Mechanical Performance of Sponge Gourd Fiber Reinforced Polyester Composites." Materials Science Forum 869 (August 2016): 203–8. http://dx.doi.org/10.4028/www.scientific.net/msf.869.203.

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The engineering applications of natural materials to replace synthetic ones has marked increased in past decades owing to environmental, societal and economical issues. Among these natural materials, the lignocellulosic fibers obtained from plants are successfully being used as polymer composites reinforcement is substitution of the traditional glass fiber. One relatively unknown lignocellulosic fiber with potential for composite reinforcement is that extracted from the sponge gourd. In the present work, the dynamic-mechanical performance of unsaturated orthophtalic polyester matrix composites was evaluated for different volume fractions of continuous and aligned sponge gourd fiber reinforcement. The results revealed that an increasing incorporation of sponge gourd fiber improved the composite viscoelastic stiffness, while decreasing its glass transition temperature.

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23

Xu, Yaopengxiao, Pei-En Chen, Hechao Li, Wenxiang Xu, Yi Ren, Wanliang Shan, and Yang Jiao. "Correlation-function-based microstructure design of alloy-polymer composites for dynamic dry adhesion tuning in soft gripping." Journal of Applied Physics 131, no. 11 (March 21, 2022): 115104. http://dx.doi.org/10.1063/5.0082515.

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Tunable dry adhesion is a crucial mechanism in compliant manipulation. The gripping force can be controlled by reversibly varying the physical properties (e.g., stiffness) of the composite via external stimuli. The maximal gripping force Fmax and its tunability depend on, among other factors, the stress distribution on the gripping interface and its fracture dynamics (during detaching), which in turn are determined by the composite microstructure. Here, we present a computational framework for the modeling and design of a class of binary smart composites containing a porous low-melting-point alloy (LMPA) phase and a polymer phase, in order to achieve desirable dynamically tunable dry adhesion. We employ spatial correlation functions to quantify, model, and represent the complex bi-continuous microstructure of the composites, from which a wide spectrum of realistic virtual 3D composite microstructures can be generated using stochastic optimization. A recently developed volume-compensated lattice-particle method is then employed to model the dynamic interfacial fracture process, where the gripper is detached from the object, to compute Fmax for different composite microstructures. We focus on the interface defect tuning mechanism for dry adhesion tuning enabled by the composite, and find that for an optimal microstructure among the ones studied here, a tenfold dynamic tuning of Fmax before and after the thermal expansion of the LMPA phase can be achieved. Our computational results can provide valuable guidance for experimental fabrication of the LMPA–polymer composites.

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24

Selver, Erdem, Nuray Ucar, and Turgut Gulmez. "Effect of stacking sequence on tensile, flexural and thermomechanical properties of hybrid flax/glass and jute/glass thermoset composites." Journal of Industrial Textiles 48, no. 2 (October 12, 2017): 494–520. http://dx.doi.org/10.1177/1528083717736102.

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This paper investigates tensile, flexural, and dynamic mechanical properties of natural and hybrid thermoset composite laminates made from flax/glass and jute/glass fibres. Hybrid laminates with various stacking sequences were manufactured by vacuum infusion method. Weight and cost of composites decreased using cheaper and lightweight natural fibres (flax and jute). Results showed that composite laminates made from natural fibres had higher specific strength values when the results were normalised to same glass fibre volume fraction, although they had lower tensile and flexural strength than that of glass composites without normalization. Composite elastic properties were predicted using classical lamination theory through rule of mixture and Halpin–Tsai models, and compared with experimental values. Changing the stacking sequence did not affect the tensile strength and modulus of composites significantly, whereas there were notable differences on flexural strength of composites when the outer layers contained glass fibres. Dynamic mechanical analyses showed similar results as flexural test, while natural fibre and some of hybrid composites had higher damping characteristics than glass-reinforced composites.

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Rehacek, Stanislav, Ivo Simunek, David Citek, and Jiri Kolisko. "Cementitious Composites in Severe Environmental Conditions - Dynamic Loading." Advanced Materials Research 1124 (September 2015): 69–75. http://dx.doi.org/10.4028/www.scientific.net/amr.1124.69.

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Structure and properties of cement composite are time-varying characteristics, depending among others on environmental conditions. The key idea of the project is a struggle for complex research of joint effect of physical, chemical and dynamic loads on the internal structure [8] of cement composite and understanding the correlation between changes in microstructure and macro-scale properties [5]. During the experimental program, specimens will be exposed to combined influence of freeze-thaw cycles [9], aggressive chemical agents and dynamic loading [7]. The aim is to create a theoretical basis for design of effective cement composites meant to be used in severe environmental conditions. Results of first dynamic load tests carried out on prismatic specimens (100x100x400 mm) are presented in this paper. The results are supplemented by ultrasonic measurement.

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26

Niu, Zhichao, and Kai Cheng. "Improved dynamic cutting force modelling in micro milling of metal matrix composites part II: Experimental validation and prediction." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 234, no. 8 (December 12, 2019): 1500–1515. http://dx.doi.org/10.1177/0954406219893725.

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The effects of cutting dynamics and the particles' size and density cannot be ignored in micro milling of metal matrix composites. This article presents the improved dynamic cutting force modelling for micro milling of metal matrix composites based on the previous analytical model. This comprehensive improved cutting force model, taking the influence of the tool run-out, actual chip thickness and resultant tool tip trajectory into account, is evaluated and validated through well-designed machining trials. A series of side milling experiments using straight flutes polycrystalline diamond end mills are carried out on the metal matrix composite workpiece under various cutting conditions. Subsequently, the measured cutting forces are compensated by a Kalman filter to achieve the accurate cutting forces. These are further compared with the predicted cutting forces to validate the proposed dynamic cutting force model. The experimental results indicate that the predicted and measured cutting forces in micro milling of metal matrix composites are in good agreement.

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Garcia, Cristobal, Irina Trendafilova, Andrea Zucchelli, and Justin Contreras. "The effect of nylon nanofibers on the dynamic behaviour and the delamination resistance of GFRP composites." MATEC Web of Conferences 148 (2018): 14001. http://dx.doi.org/10.1051/matecconf/201814814001.

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Vibrations are responsible for a considerable number of accidents in aircrafts, bridges and other civil engineering structures. Therefore, there is a need to reduce the vibrations on structures made of composite materials. Delamination is a particularly dangerous failure mode for composite materials because delaminated composites can lose up to 60% of their strength and stiffness and still remain unchanged. One of the methods to suppress vibrations and preventing delamination is to incorporate nanofibers into the composite laminates. The aim of the present work is to investigate how nylon nanofibers affect the dynamic behaviour and delamination resistance of glass fibre reinforced polymer (GFRP) composites. Experiments and numerical simulations using finite element modelling (FEM) analysis are used to estimate the natural frequencies, the damping ratio and inter-laminar strength in GFRP composites with and without nylon nanofibers. It is found that the natural frequencies of the nylon nano-modified composites do not change significantly as compared to the traditional composites. However, nano-modified composites demonstrated a considerable increase in damping ratio and inter-laminar shear strength due to the incorporation of nylon nanofibers. This work contributes to the knowledge about the mechanical and dynamic properties of glass fibre reinforced polymer (GFRP) composites with nylon nanofibers.

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Yang, Zhi Ming, Jin Xu Liu, Xin Ya Feng, Shu Kui Li, Xin Lei Wang, and Yong Ji Gao. "Effect of Carboxylic CNTs Filling on Mechanical Behaviors of Basalt Fiber/Epoxy Composites." Materials Science Forum 913 (February 2018): 529–35. http://dx.doi.org/10.4028/www.scientific.net/msf.913.529.

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In order to improve the mechanical properties of basalt fiber/epoxy composites, carboxylic CNTs were filled into the epoxy matrix of basalt fiber/epoxy composites. Firstly, the carboxylic CNTs filled epoxy composites with different carboxylic CNTs content were studied. Quasi-static and dynamic compression results show that when the content of carboxylic CNTs increased from 0wt% to 1wt%, both ultimate quasi-static and dynamic compressive strength of CNTs filled epoxy composites showed increasing tendencies. However when the content of carboxylic CNTs increased from 1 wt% to 1.5 wt% both ultimate quasi-static and dynamic compressive had decreasing tendencies. Base on above results, carboxylic CNTs (1wt%) filled basalt fiber/epoxy composites were fabricated by mould pressing method. Quasi-static and dynamic compression results showed that both ultimate quasi-static and ultimate dynamic compressive strength of carboxylic CNTs filled basalt fiber/epoxy composite were enhanced compared with those of basalt fiber/epoxy composites without CNTs. However, the critical failure strain were all lower than those of basalt fiber/epoxy composites without CNTs. Failure mechanism analysis showed that the carboxylic CNTs was beneficial for forming good interfacial bonding between epoxy matrix and basalt fibers, and the advantage of high axial tensile strength of basalt fibers could be fully utilized, which is responsible for the enhanced ultimate compressive strength of carboxylic CNTs filled basalt fiber/epoxy composites.

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29

Hosur, M. V., Jessie B. Mayo Jr., E. Wetzel, and S. Jeelani. "Studies on the Fabrication and Stab Resistance Characterization of Novel Thermoplastic-Kevlar Composites." Solid State Phenomena 136 (February 2008): 83–92. http://dx.doi.org/10.4028/www.scientific.net/ssp.136.83.

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Kevlar has demonstrated the ability to protect well against ballistic threats but has low resistance to puncture. Correctional Kevlar has shown good resistance to puncture. However, the fabric is expensive, difficult to manufacture because of its tight weave construction, and has limited protection against ballistic threats. In an effort to produce materials that are less bulky, more flexible, and resistant to puncture, thermoplastic-Kevlar (TP-Kevlar) composites have been examined. Kevlar fabric was impregnated with thermoplastic film using a hot press to produce the composites. Static and dynamic puncture resistant properties of the TP-Kevlar composites were investigated using a National Institute of Justice (NIJ Standard 0115.00) Stab Tower. The TP-films used in this study were polyethylene, Surlyn, and co extruded-Surlyn, which is a co extrusion of Surlyn and polyethylene. Response of the polyethylene (PE)-Kevlar composites, Surlyn-Kevlar composites, and co extruded (COEX)-Kevlar composites to spike and knife threats under static and dynamic conditions were compared with that of neat Kevlar. The infusion of thermoplastic films into the Kevlar fabric was shown to dramatically increase puncture resistance during quasi-static and dynamic testing with spikes. The TP-film type also made a difference when examining the resistance on a comparative basis of the TP-Kevlar targets. The TP-Kevlar composite targets showed more resistance to quasi-static spike testing than quasi-static knife testing. Weapon comparisons revealed that the TP-Kevlar composite targets had more resistance to dynamic knife testing than dynamic spike testing.

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Wang, X. D., and S. Gan. "Effective Antiplane Dynamic Properties of Fiber-Reinforced Composites." Journal of Applied Mechanics 69, no. 5 (August 16, 2002): 696–99. http://dx.doi.org/10.1115/1.1480819.

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This paper provides an theoretical analysis of the properties of fibre reinforced composite materials under antiplane waves. A self-consistent scheme is adopted in calculating the effective material constants. A new averaging technique is developed to account for the effects of the waveform. The model is then used to evaluate the effective dynamic properties of composites with randomly distributed fibers. Typical examples are presented to show the effects of different pertinent parameters upon the effective wave speed and the attenuation.

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F, Michael Raj, Sahaya Elsi S, Emina M S, Freeda S, Amala Midun Minther Singh A, and Jayaram R S. "Dynamic Mechanical Analysis of Hybrid Composites of Discarded Fishnet and Glass Fibre Reinforcement with Polyester Matrix." Journal of Manufacturing Engineering 16, no. 2 (June 1, 2021): 051–60. http://dx.doi.org/10.37255/jme.v16i2pp051-060.

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Polyester based composites were fabricated and characterized for their tensile, morphological and dynamic mechanical properties such as storage and loss moduli as a function of temperature. The morphological attributes were characterized by scanning electron microscopy (SEM) and COSLAB microscope. The morphological investigations have revealed a uniformly distributed polyester matrix of the composites. Dynamic mechanical analysis (DMA) revealed an enhancement in the energy dissipation ability of the composite 4GF and an average storage modulus of the composite 3GF/1FN relative to the soft polyester phase. The tensile modulus and tensile strength increased up to 0.5 %, accompanied by while the strain at break remained largely unaffected. Fractured surface morphology indicates that the failure mode of the composites undergoes a switch-over from matrix-controlled shear deformation to the filler-controlled loading of the composites for specific applications. Hence, the utilization of discarded fishnet incorporated composites mitigates the problem of waste disposal.

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32

Polilov, A. N., A. F. Melshanov, N. A. Tatous, and N. A. Makhutov. "Dynamic experimental investigations of composites." Journal de Physique IV (Proceedings) 110 (September 2003): 559–64. http://dx.doi.org/10.1051/jp4:20020752.

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33

Blekhman, I. I. "Vibrational dynamic materials and composites." Journal of Sound and Vibration 317, no. 3-5 (November 2008): 657–63. http://dx.doi.org/10.1016/j.jsv.2008.03.015.

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34

Vyrovoy, V., and V. Sukhanov. "STRUCTURAL DYNAMIC OF BUILDING COMPOSITES." Mechanics And Mathematical Methods 1, no. 2 (November 29, 2019): 27–35. http://dx.doi.org/10.31650/2618-0650-2019-1-2-27-35.

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35

Gao, Chong Yang, Jian Zhang Xiao, Liang Chi Zhang, and Ying Lin Ke. "On the static and dynamic properties of fiber-reinforced polymer composites." Journal of Thermoplastic Composite Materials 30, no. 11 (April 28, 2016): 1560–77. http://dx.doi.org/10.1177/0892705716646418.

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This article establishes a reliable constitutive model to describe the behaviors of fiber-reinforced polymer composites under quasi-static and dynamic loading. This model integrates the contributions of all the three phases of a composite: the fiber, the matrix, and the fiber/matrix interphase, which make it capable of capturing the key micromechanical effect of the interphase on the macroscopic mechanical properties of composites. The interphase is taken as a transversely isotropic material together with the fiber. By analyzing glass/epoxy and carbon/epoxy composites, it was found that the model predictions agree well with the experimental data and the model is more effective particularly when the fiber volume fraction is high. The dynamic three-phase model was also established by using the coupling of the elastic and Maxwell elements for the viscoelasticity of the matrix as well as the interphase. The article concludes that the three-phase model with consideration of the interphase influence can precisely characterize the static and dynamic mechanical properties of a FRP composite.

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Oliveira, Michelle Souza, Fernanda Santos da Luz, Fabio da Costa Garcia Filho, Artur Camposo Pereira, Vinícius de Oliveira Aguiar, Henry Alonso Colorado Lopera, and Sergio Neves Monteiro. "Dynamic Mechanical Analysis of Thermally Aged Fique Fabric-Reinforced Epoxy Composites." Polymers 13, no. 22 (November 22, 2021): 4037. http://dx.doi.org/10.3390/polym13224037.

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Dynamic mechanical analysis (DMA) is one of the most common methods employed to study a material’s viscoelastic properties. The effect of thermal aging on plain epoxy and a fique fabric-reinforced epoxy composite was investigated by comparing the mass loss, morphologies, and DMA properties of aged and unaged samples. In fact, thermal aging presents a big challenge for the high-temperature applications of natural fiber composites. In this work, both plain epoxy and fique fabric-reinforced epoxy composite were found to have different molecular mobility. This leads to distinct transition regions, with different changes in intensity caused by external loadings from time-aging. Three exponentially modified Gauss distribution functions (EMGs) were applied to loss factor curves of fique fabric-reinforced epoxy composite and plain epoxy, which allowed identifying three possible mobility ranges. From these results it was proposed that the thermal degradation behavior of natural fibers, especially fique fiber and their composites, might be assessed, based on their structural characteristics and mechanical properties.

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37

Arrieta, Andres F., Onur Bilgen, Michael I. Friswell, and Peter Hagedorn. "Dynamic control for morphing of bi-stable composites." Journal of Intelligent Material Systems and Structures 24, no. 3 (June 27, 2012): 266–73. http://dx.doi.org/10.1177/1045389x12449918.

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Adaptive structures have been the focus of much research due to performance gains not possible to achieve using conventional designs. Within this context, the idea of morphing promises augmented capabilities in terms of manoeuvrability, fuel efficiency and the ability to perform dissimilar tasks in an optimal manner. To achieve morphing, materials capable of changing shape requiring minimum actuation are necessary. Bi-stable composites are a type of composite structures which have two statically stable configurations. This bi-stability property, resulting from locked in-plane residual stresses, has attracted considerable attention from the adaptive structure community for morphing structures as actuation is no required to hold each stable configuration. The change between stable states is physically realised as a jump phenomenon or snap-through, which is strongly non-linear in nature. Morphing strategies exploiting snap-through have been studied showing encouraging preliminary results. This article exploits the dynamic response of bi-stable composites as a means of augmenting the actuation for morphing control. A morphing strategy targeting modal frequencies leading to snap-through of the structure is successfully developed. This results in a full-state configuration control by inducing and reversing snap-through as desired. The strategy is tested on a specimen using Macro Fiber Composites as smart actuators validating the proposed concept.

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38

Hu, Hai Xia, Zhao Zheng Liu, and Wei Dong Liu. "High Strain-Rate Compressive Response of Epoxy Composites." Applied Mechanics and Materials 217-219 (November 2012): 138–41. http://dx.doi.org/10.4028/www.scientific.net/amm.217-219.138.

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The high strain rate compressive behavior of a bicomponent high performance epoxy resin for advanced composites filled with Polyaryletherketone (PAEK) has been studied on a modified split Hopkinson Pressure Bar (SHPB) setup under dynamic loading conditions. Dynamic stress-strain plot was obtained for each sample. The results of the study indicated that the plastic of the epoxy composites increased while yield strength decreases slightly with the increase of the content of PAEK powder. In contrast, EP/PAEK-10 composite has the best Compressive properties.

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39

Tan, Hao, Hong Sheng Tan, Xin Lei Tang, Yan Gang Wang, and Li Ping Li. "Mechanical Properties and Dynamic Mechanical Behavior for Long Aramid Fiber Reinforced Impact Polypropylene Copolymer." Advanced Materials Research 591-593 (November 2012): 1079–82. http://dx.doi.org/10.4028/www.scientific.net/amr.591-593.1079.

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Composites of continuous aramid fiber reinforced impact polypropylene copolymer (IPC) were prepared using a cross-head impregnation mold by self-design fixed on a single screw extruder, and pelleted by a pelleter for injection molding to prepare testing specimens. The mechanical properties of long aramid fibers reinforced impact polypropylene copolymer (IPC) composites were studied. Micrographs of fracture surface of tensile specimens and dynamic mechanical behavior for the composites were analyzed by scanning electron microscope (SEM) and dynamic mechanical analyzer (DMA). The results of experiments show that, the tensile and flexural strengths increased obviously with the aramid fibers content in the composites. SEM results show the compatibility between the aramid fiber and matrix is very poor. The results of the dynamic mechanical behavior of long aramid fibers reinforced IPC composites show that the composite deformation resistance and glass transition temperature increased evidently with the addition of aramid fibers.

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40

Manoharan, Sembian, Bhimappa Suresha, Govindarajulu Ramadoss, and Basavaraj Bharath. "Effect of Short Fiber Reinforcement on Mechanical Properties of Hybrid Phenolic Composites." Journal of Materials 2014 (August 6, 2014): 1–9. http://dx.doi.org/10.1155/2014/478549.

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Fiber plays an important role in determining the hardness, strength, and dynamic mechanical properties of composite material. In the present work, enhancement of viscoelastic behaviour of hybrid phenolic composites has been synergistically investigated. Five different phenolic composites, namely, C1, C2, C3, C4, and C5, were fabricated by varying the weight percentage of basalt and aramid fiber, namely, 25, 20, 15, 10, and 5% by compensating with barium sulphate (BaSO4) to keep the combined reinforcement concentration at 25 wt%. Hardness was measured to examine the resistance of composites to indentation. The hardness of phenolic composites increased from 72.2 to 85.2 with increase in basalt fiber loading. Composite C1 (25 wt% fiber) is 1.2 times harder than composite C5. Compression test was conducted to find out compressive strength of phenolic composites and compressive strength increased with increase in fiber content. Dynamic mechanical analysis (DMA) was carried out to assess the temperature dependence mechanical properties in terms of storage modulus (E′), loss modulus (E′′), and damping factor (tan δ). The results indicate great improvement of E′ values and decrease in damping behaviour of composite upon fiber addition. Further X-ray powder diffraction (XRD) and energy-dispersive X-ray (EDX) analysis were employed to characterize the friction composites.

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41

Zhou, Yonghui, David Hui, Yuxuan Wang, and Mizi Fan. "Nanomechanical and dynamic mechanical properties of rubber–wood–plastic composites." Nanotechnology Reviews 11, no. 1 (December 23, 2021): 167–75. http://dx.doi.org/10.1515/ntrev-2022-0002.

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Abstract This article presents the assessment of bulk and in situ mechanical properties of rubber–wood–plastic composites (RubWPC) and their correlations, aiming to obtain a thorough understanding of mechanical behaviour of RubWPC, which is an essential prerequisite in realising their optimal design and applications. Dynamic mechanical analysis results showed that the composites treated with multiple coupling agents (combination of maleic anhydride polyethylene [MAPE] and bis(triethoxysilylpropyl)tetrasulfide and combination of MAPE and vinyltrimethoxysilane) exhibited greater storage modulus than both the untreated and single coupling agent treated composites owing to their superior interfacial bonding quality. The shift of relaxation peak and T g towards higher temperatures observed in the treated composites confirmed the enhancement of interfacial interaction and adhesion. Nanoindentation analysis suggested that the composite with optimised interface (MAPE and Si69 treated) possessed better nanomechanical property (elastic modulus) due to the resin penetration into cell lumens and vessels and the reaction between cell walls and coupling agents.

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42

Murčinková, Zuzana, and Michal Halapi. "Analysis of the material configurations and influence on the dynamic response." MATEC Web of Conferences 157 (2018): 05018. http://dx.doi.org/10.1051/matecconf/201815705018.

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The paper presents the analysis of the material configuration of composites based on the measurement of their dynamic response. The article presents the measurement scheme, the design of the measuring stand together with the analysis of the results. Moreover, it analyses the FFT spectrums of layered long fibre composite, short fibre composites of different fibres materials and homogeneous materials as steel and aluminium alloy.

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43

Srivastava, Ankit, and Sia Nemat-Nasser. "Overall dynamic properties of three-dimensional periodic elastic composites." Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences 468, no. 2137 (September 21, 2011): 269–87. http://dx.doi.org/10.1098/rspa.2011.0440.

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This article presents a method for the homogenization of three-dimensional periodic elastic composites. It allows for the evaluation of the averaged overall frequency-dependent dynamic material constitutive tensors relating the averaged dynamic field variable tensors of velocity, strain, stress and linear momentum. Although the form of the dynamic constitutive relation for three-dimensional elastodynamic wave propagation has been known, this is the first time that explicit calculations of the effective parameters (for three dimensions) are presented. We show that for three-dimensional periodic composites, the overall compliance (stiffness) tensor, as produced directly by our formulation, is Hermitian, regardless of whether the corresponding unit cell is geometrically or materially symmetric. Overall, mass density is shown to be a tensor and, like the overall compliance tensor, always Hermitian. The average strain and linear momentum tensors are, however, coupled, and the coupling tensors are shown to be each others' Hermitian transpose. Finally, we present a numerical example of a three-dimensional periodic composite composed of elastic cubes periodically distributed in an elastic matrix. The presented results corroborate the predictions of the theoretical treatment illustrating the frequency dependence of the constitutive parameters. We also show that the effective properties calculated in this paper satisfy the dispersion relation of the composite.

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44

Pereda, B., Beatriz López, and J. M. Rodriguez-Ibabe. "Relevance of Static and Dynamic Recrystallizations on Austenite Grain Refinement in Nb-Mo Microalloyed Steels." Materials Science Forum 638-642 (January 2010): 687–92. http://dx.doi.org/10.4028/www.scientific.net/msf.638-642.687.

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Composite systems composed of nanocrystalline apatites and oligolactide-based polymer networks were prepared resulting in malleable and even injectable formulations which can be cured to compact materials at body temperature. Porous devices with inter-connective porosity were obtained after addition of suitable foaming agents to the composite mixtures. Setting time, porosity and mechanical properties of the composites can be properly adjusted by varying the educt composition. The determined compressive strengths and Young’s moduli of the porous composites perfectly match the mechanical characteristics of cancellous bone material. Preliminary in vitro cell culture experiments with compact composite materials demonstrated their good cytocompatibility. Based on these findings, the synthesized nano-structured composites represent promising candidates for the development of new biomaterials usable in hard tissue regeneration.

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45

Shen, W. C., L. L. Lin, C. Y. Shen, S. Xing, and Z. B. Pan. "Dynamic magnetoelastic properties of TbxHo0.9−xNd0.1(Fe0.8Co0.2)1.93/epoxy composites." Materials Science-Poland 37, no. 2 (June 1, 2019): 257–64. http://dx.doi.org/10.2478/msp-2019-0027.

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AbstractTbxHo0.9−xNd0.1(Fe0.8Co0.2)1.93/epoxy (0 ⩽ x ⩽ 0.40) composites are fabricated in the presence of a magnetic field. The structural and dynamic magnetoelastic properties are investigated as a function of both magnetic bias field Hbias and frequency f at room temperature. The composites are formed as textured orientation structure of 1–3 type with 〈1 0 0〉 preferred orientation for x ⩽ 0.10 and 〈1 1 1〉-orientation for x ⩾ 0.25. The composites generally possess insignificant eddy-current losses for frequency up to 50 kHz, and their dynamic magnetoelastic properties depend greatly on Hbias. The elastic modulus (E3H and E3B) shows a maximum negative ΔE effect, along with a maximum d33, at a relatively low Hbias ~ 80 kA/m, contributed by the maximum motion of non-180° domain-wall. The 1–3 type composite for x ⩾ 0.25 shows an enhanced magnetoelastic effect in comparison with 0 to 3 type one, which can be principally ascribed to its easy magnetization direction (EMD) towards 〈1 1 1〉 axis and the formation of 〈1 1 1〉-texture-oriented structure in the composite. These attractive dynamic magnetoelastic properties, e.g., the low magnetic anisotropy and d33,max as high as 2.0 nm/A at a low Hbias ~ 80 kA/m, along with the light rare-earth Nd element existing in insulating polymer matrix, would make it a promising magnetostrictive material system.

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46

Pei, Xiaoyuan, Li Chen, Yan Gao, Jialu Li, and Youhong Tang. "Effect of reinforcement structures on vibration performance of composites." Journal of Composite Materials 51, no. 22 (January 25, 2017): 3149–61. http://dx.doi.org/10.1177/0021998316689602.

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In this study, the composites with different reinforcement structures, namely three-dimension and five-direction braided, three-dimension and four-direction braided, and laminated structures, are designed and the effects of different reinforcement structures on the vibration properties of the corresponding composites were analyzed. The dynamic properties of the braided composites and laminated composites were compared. Multivariate analysis of variance demonstrated that the structure of the reinforcement had a significant effect on the natural frequency and damping ratio of the composites. The composites with advanced braided structure had the good dynamic mechanics behavior, such as relatively high natural frequency, damping ratio, and the ratio of stiffness to weight, as well as fairly good stabilization. This study provides the basis for composite design and the selection of reinforcement structures under different conditions.

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47

Kosicka, Ewelina, Marek Borowiec, Marcin Kowalczuk, and Aneta Krzyzak. "Dynamic Behavior of Aviation Polymer Composites at Various Weight Fractions of Physical Modifier." Materials 14, no. 22 (November 15, 2021): 6897. http://dx.doi.org/10.3390/ma14226897.

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The aim of this study was to determine the effect of a selected physical modifier with different granularity and mass percentage on the dynamics of aerospace polymer composites. The tests were carried out on samples made of certified aerospace materials used, among other purposes, for the manufacture of aircraft skin components. The hybrid composites were prepared from L285 resin, H286 hardener, GG 280T carbon fabric in twill 2/2 and alumina (Al2O3, designated as EA in this work). The manufactured composites contained alumina with grain sizes of F220, F240, F280, F320 and F360. The mass proportion of the modifier in the tested samples was 5% and 15%. The tested specimens, as cantilever beams fixed unilaterally, were subjected to kinematic excitation with defined parameters of amplitude and frequency excitation in the basic resonance zone of the structure. The results, obtained as dynamic responses, are presented in the form of amplitude–frequency characteristics. These relationships clearly indicate the variable nature of composite materials due to modifier density and grain size. The novelty of this study is the investigation of the influence of the alumina properties on system dynamics responses.

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48

Murčinková, Zuzana, Przemysław Postawa, and Jerzy Winczek. "Parameters Influence on the Dynamic Properties of Polymer-Matrix Composites Reinforced by Fibres, Particles, and Hybrids." Polymers 14, no. 15 (July 28, 2022): 3060. http://dx.doi.org/10.3390/polym14153060.

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In this paper, we present an extensive experimental study on the dynamic mechanical properties of composites with polymer matrices, as well as a quantification of the parameters that influence these properties. Polymer-composite matrices make it possible to form any reinforcement arrangement of fibres, particles, and layers, which makes it possible to form composite materials with certain dominant mechanical properties according to the internal arrangement for the application. In this study, we focused on the dynamic properties (i.e., damping parameters, such as the loss factor (tan d), logarithmic decrement (λ), storage modulus (E′), and loss modulus (E″)) of composites with polymer matrices, including parameters such as the fibre material, fabric weaving, fibre orientation, temperature, frequency, particle size, volume of short fibres, and epoxy resin type. If other articles focus on one type of composite and 1–2 parameters, then the benefit of this article lies in our analysis of 8 mentioned parameters in the experimental analysis of 27 different types of composites with polymer matrices. The tested fibre materials were glass, aramid, and carbon; the tested woven fabrics were twill, plain, unidirectional, and satin; the temperature range was from −50 to +230 °C; the frequency was 1 Hz and 10 Hz; the particle size was 0.1–16 mm; the volume percentages of the short fibres were 3, 6, and 12 vol.% of the hybrid polymer composites and the type of polymer matrix. We used the free-damped-vibration method with vibration dynamic signal analysis and the forced-damped vibration of dynamic mechanical thermal analysis for testing. We ranked the parameters that influence the dynamic vibration properties according to the effects. Among sets of results provided in the paper, considering the storage modulus, loss modulus, and loss factor, the best results of the fibre composites were for aramid-fibre-reinforced polymers, regardless of the weave type, with an advantage for unidirectional fabric. The best results of the particle composites were for those with fine filler sizes that incorporated the short fibres.

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Moustafa, Essam, Khalid Almitani, and Hossameldin Hussein. "Effect of Crack Orientation on Laminated CFRP Composites Using Vibration and Numerical Analysis." Materials Evaluation 79, no. 11 (November 1, 2021): 1081–93. http://dx.doi.org/10.32548/2021.me-04205.

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Crack orientation, a critical parameter, significantly affects the dynamic properties of composite structures. Experimental free vibration tests were conducted on carbon fiber–reinforced polymer (CFRP) composite plates at room temperature with different crack orientations. Dynamic properties such as damping ratio, natural frequency, and storage modulus were measured using a four-channel dynamic pulse analyzer. Multi-sensors were mounted on the test plate to pick up the vibration signals. Experimental modal analysis was performed to identify the first three mode shapes of the defective plates. A numerical model using ANSYS software was developed via parametric investigation to predict the correlation between crack orientation and resonant frequencies with corresponding mode shapes. The orientation of the introduced cracks had a significant effect on the dynamic properties of CFRP composites. Vertical cracks had the most significant influence on the eigenvalues of the mode shape frequencies. Furthermore, the damping ratio was an effective method to detect the cracks in CFRP composites.

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Medvedskiy, Aleksandr L., Mikhail I. Martirosov, and Anton V. Khomchenko. "Numerical analysis of layered composite panel behavior with interlaminar defects subject to dynamic loads." Structural Mechanics of Engineering Constructions and Buildings 15, no. 2 (December 15, 2019): 127–34. http://dx.doi.org/10.22363/1815-5235-2019-15-2-127-134.

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Aims of research. Polymer unidirectional composite laminate panel behavior with interlaminate defects under action of different dynamic loads is consider. Methods. Normal modes and eigenvalues of rectangular composite panels in the presence multiple delamination different sizes ellipsoidal form are calculated. The dependences of the maximum deflections from the frequency of the stationary pressure field action are constructed. Distribution field of panels plies failure index under action of nonstationary pressure field by using different failure criteria for composites is determined. Results. Modeling methodology composite panels behavior in the presence multiple interlaminar defects under action of different dynamic loads is developed. Analysis of failure panel with the use of different failure criteria for composites is carried out.

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