Preparation,Morphology and Damping Property of PU/UP Interpenetrating Polymer Networks

Interpenetrating polymer networks （IPNs） composed of acrylate-modified polyurethane （PU）/unsaturated polyester （UP） resin via simultaneous polymerization with various component ratios of PU/UP were prepared. The polymerization processes of IPNs were traced through infrared spectrum （IR） techniques, by which the phase separation in systems could be controlled effectively. Results for the morphology and miscibility among multiple phases of IPNs, obtained by transmission electron microscope （TEM） indicated that the domains between two phases were constricted in nanometer scales. The dynamic mechanical thermal analyzer （DMTA） detection results revealed that the loss factor （tanS） and loss modulus （E″） increased with the polyurethane amounts in system, and the peak value in curves of tanδ and E″ appeared toward low temperature ranges. Maximum tanδ values of all samples were above 0.3 in the nearly 50℃ ranges. Also, the mechanical properties of PU/UP IPNs were studied in detail.

Damping Property of Supersaturated ZnA127Ce Alloy during Natural Aging

The microstructures and damping property of supersaturated ZnA127Ce alloy during natural aging have been investigated. H-800 TEM was mainly used to research the microstructures. The relationship between microstructure and damping property was primarily studied. The results showed that solution plus natural aging was the best heat treatment, which could improve the damping property. Both continuous precipitation and cellular reaction occurred during the aging. Continuous precipitation follows the sequence: β→spherical GP zones→elliptical GP zones→intermediate phase R→n. The cellular reaction can be written as follows:β→a+n+ε.

The Influence of Fiber Type and Conformation on the Damping Property of FRP Composite

In order to get a fiber reinforced plastic（FRP） composite with good damping property as well as good mechanical properties, different types of reinforcing materials were used to reinforcing a damping resin. The influence of fiber types and conformation on the damping property of the composite are tested. Compared to the glass fiber（GF）, carbon fiber（CF） can improve the damping factor of the composites; the highest tanδ value is 0.827 while the Tg is 22.5 ℃. The style of the fibers also influences the damping factors of the composite. The composite reinforced with mat has higher loss factors than that composite reinforced with clothe for the reason that the former has the ability to deform and the composite has higher resin content. The loss factor of GF mat reinforced composite is 0.704 while the Tg is 27 ℃. Both composite has good damping properties and can be used as the damping layer of the structural damping composite.

The Influence of Carbon Nanotubes and Nano-Silica Fume on Enhancing the Damping and Mechanical Properties of Cement-Based Materials

This paper conducted experimental studies on the damping and mechanical properties of carbon nanotube-nanosilica-cement composite materials with different carbon nanotube contents. The damping and mechanical properties enhancement mechanisms were analyzed and compared through the porosity structure test, XRD analysis, and scanning electron microscope observation. The results show that the introduction of nanosilica significantly improves the dispersion of carbon nanotubes in the cement matrix. At the same time, the addition of nanosilica not only effectively reduces the critical pore size and average pore size of the cement composite material, but also exhibits good synergistic effects with carbon nanotubes, which can significantly optimize the pore structure. Finally, a rationalization suggestion for the co-doping of nanosilica and carbon nanotubes was given to achieve a significant increase in the flexural strength, compressive strength and loss factor of cement-based materials.

Microstructure and damping properties of LPSO phase dominant Mg-Ni-Y and Mg-Zn-Ni-Y alloys

This work studied the microstructure,mechanical properties and damping properties of Mg_(95.34)Ni_(2)Y_(2.66) and Mg_(95.34)Zn_(1)Ni_(1)Y_(2.66)alloys systematically.The difference in the evolution of the long-period stacked ordered(LPSO)phase in the two alloys during heat treatment was the focus.The morphology of the as-cast Mg_(95.34)Ni_(2)Y_(2.66)presented a disordered network.After heat treatment at 773 K for 2 hours,the eutectic phase was integrated into the matrix,and the LPSO phase maintained the 18R structure.As Zn partially replaced Ni,the crystal grains became rounded in the cast alloy,and lamellar LPSO phases and more solid solution atoms were contained in the matrix after heat treatment of the Mg_(95.34)Zn_(1)Ni_(1)Y_(2.66)alloy.Both Zn and the heat treatment had a significant effect on damping.Obvious dislocation internal friction peaks and grain boundary internal friction peaks were found after temperature-dependent damping of the Mg_(95.34)Ni_(2)Y_(2.66)and Mg_(95.34)Zn_(1)Ni_(1)Y_(2.66)alloys.After heat treatment,the dislocation peak was significantly increased,especially in the alloy Mg_(95.34)Ni_(2)Y_(2).66.The annealed Mg_(95.34)Ni_(2)Y_(2.66)alloy with a rod-shaped LPSO phase exhibited a good damping performance of 0.14 atε=10^(−3),which was due to the difference between the second phase and solid solution atom content.These factors also affected the dynamic modulus of the alloy.The results of this study will help in further development of high-damping magnesium alloys.

Damping properties and mechanism of aluminum matrix composites reinforced with glass cenospheres

The damping properties were improved by preparing Al matrix composites reinforced with glass cenospheres through the pressure infiltration method.Transmission electron microscopy and scanning electron microscopy were employed to characterize the microstructure of the composites.The low-frequency damping properties were examined by using a dynamic mechanical thermal analyzer,aiming at exploring the changing trend of damping capacity with strain,temperature,and frequency.The findings demonstrated that the damping value rose as temperature and strain increased,with a maximum value of 0.15.Additionally,the damping value decreased when the frequency increased.Dislocation damping under strain and interfacial damping under temperature served as the two primary damping mechanisms.The increase in the density of dislocation strong pinning points following heat treatment reduced the damping value,which was attributed to the heat treatment enhancement of the interfacial bonding force of the composites.

Research Analysis on the Microscopic Properties and Damping Performance of Carbon Nanomaterial-Modified Cement Mortar

The application of carbon nanomaterials, particularly graphene and carbon nanotubes, in cement-based composites is highly significant. These materials demonstrate the multifunctionality of carbon and offer extensive possibilities for technological advancements. This research analyzes how the integration of graphene into cement-based composites enhances damping and mechanical properties, thereby contributing to the safety and durability of structures. Research on carbon nanomaterials is ongoing and is expected to continue driving innovation across various industrial sectors, promoting the sustainable development of building materials.

A Review of Influencing Factors of Damping Properties of High Manganese Steel

High manganese steel has wide prospects in industry due to their excellent mechanical and damping properties. The quenching structures of high manganese steel are ε-martensite, γ-austenite and α'-martensite. Researches show that the damping properties of high manganese steel are related to these microstructures. Besides, there are many ways to improve the damping property of damping alloys. This paper reviews the damping mechanism and the influences of the ad-dition of alloying elements, heat treatment, pre-deformation and other factors on their damping performance, hoping to provide methods and ideas for the study of damping properties of high manganese steel. .

Evaluation of properties for a passive damping device with TiNi alloy rings as energy dissipating element

A new kind of passive damping device that is composed of TiNi shape memory alloy （SMA） rings is designed.The basic mechanical behaviors of the device are investigated and its damping capacity is analyzed.There still exist hysteresis loops during loading and unloading when the deformation of the ring（s） is restricted in the horizontal direction properly,but the force-displacement curves are tilted and not parallel to the abscissa,which can improve the ability to withstand overloading.If there is no restriction,the force-displacement curves of the rings are near linear though the unloading paths are slightly different from those of loading.The basic mechanical and damping properties of the device may be changed by using different numbers of TiNi alloy rings,and the damping capacity will be increased markedly by increasing the number of rings.

Damping properties of fly ash/epoxy composites

An inexpensive fly ash （FA）, which is from a waste product, was employed to prepare fly ash/epoxy composites. The purpose of this study is to characterize the contributions of matrix viscoelasticity, hollow structure characteristic （porosity）, and filler/matrix interface friction to the high vibration damping capacity of such composites. The damping properties of the composites were investigated in the temperature range of-40 to 150℃ and in the frequency range of 10 to 800 Hz by using a tension-compression mode. The results indicate that the peak value of damping loss factor （tan3） for the fly ash/epoxy composites can reach 0.70-0.90 in test specification, and the attenuation of damping loss factor is inconspicuous with increasing frequency. In addition, scanning electron microscope （SEM） was used to observe the morphology of the fly ash as well as its distribution in the matrix, which will help to analyze the effect of fly ash on the damping properties of the fly ash/epoxy composites.

Damping of Magnetorheological Elastomers

The damping property of magnetorheological （MR） elastomers is characterized by a modified dynamic mechanical-magnetic coupled analyzer. The influences of the external magnetic flux density, damping of the matrix, content of iron particles, dynamic strain, and driving frequency on the damping properties of MR elastomers were investigated experimentally. The experimental results indicate that the damping properties of MR elastomers greatly depend on the interfacial slipping between the inner particles and the matrix. Different from general composite materials, the interracial slipping in MR elastomers is affected by the external applied magnetic field.

DAMPING PROPERTIES OF MARTENSITE AND MARTENSITIC TRANSFORMATION IN CuZnAl ALLOYS

The internal friction of alloys in martensite state is believed to be an M/M interface one, which can be explained by an expression deduced from the theory of dislocation internal fric- tion.The internal friction during martensitic transformation consists of two parts,including those of the M/M interface and of the phase transformation.The latter is further composed of two portions,the major one produced by reverse martensitic transformation and the other from stress-induced martensite.It was also found that the degradation of damping properties of the CuZnAl alloys is related to the dislocation,which is introduced from the exciting pro- cess,and tends to be of stable value after certain excitements.

Damping Properties of Flexible Epoxy Resin

Amino-terminated polyethers and amino-terminated polyurethane were used as curing agent to cure the epoxy resin together and get a series of cured products. The damping properties of the composites were studied by DMA test at different measurement frequencies. Damping mechanical tests show that the flexible epoxy resin has higher loss factor than common epoxy. The highest loss factor reaches 1.57. Also the height and position of loss factor peak of the flexible epoxy resin varies by changing the content of amino-terminated polyethers. Results shows that the flexible epoxy resin can be used as damping polymer materials at room temperature or in common frequency range.

Mechanism of improving strength and damping properties of powder-extruded Al/Zn composite after diffusion annealing

In order to develop high strength,high damping and low density Al matrix composites,the Al/Zn composite bar samples with Zn mass fraction of 10%-40%were prepared by powder extrusion.The tensile strength and damping properties of the samples are improved by controlling both the Zn/Al diffusion degree and the precipitation of the interfacial phases.The results show that the tensile strength of the samples with Zn mass fraction of 10%-30%increases with the increases of both the Zn content and annealing temperature.When the Zn mass fraction increases to 40%,the tensile strength of the sample remains basically unchanged or decreases slightly,and the plasticity decreases gradually.Alloying of Al matrix and the formation of Zn/Al interface layer are mainly responsible for improving the strength of the annealed samples.The damping properties increase with the increases of both the Zn content and annealing temperature.The Zn/Al eutectoid lamella eliminates the detrimental effects on damping properties due to both alloying of the Al matrix and reduction of pure Zn in the Al matrix.The Al-30%Zn sample annealed at 350°C for 0.5 h has good comprehensive properties,including the tensile strength of 330 MPa,the elongation to failure of 10%and the room-temperature damping properties(tanθ)of 0.025.

Effects of Fiber Volume Fraction on Damping Properties of Three-Dimensional and Five-Directional Braided Composites

The effects of fiber volume fraction on damping properties of carbon fiber three-dimensional and five-directional( 3D-5Dir)braided carbon fiber / epoxyres in composite cantilever beams were studied by experimental modal analysis method. Meanwhile,carbon fiber plain woven laminated / epoxy resin composites with different fiber volume fraction were concerned for comparison. The experimental result of braided specimens shows that the first three orders of natural frequency increase and the first three orders of the damping ratios of specimens decrease, when the fiber volume fraction increases. Furthermore,larger fiber volume fraction will be valuable for the better anti-exiting property of braided composites,and get an opposite effect on dissipation of vibration energy. The fiber volume fraction is an important factor for vibration performance design of braided composites. The comparison between the braided specimens and laminated specimens reveals that 3D braided composites have a wider range of damping properties than laminated composites with the same fiber volume fractions.

On the Damping Properties of Modified Ground Rubber Tires

Large amounts of used rubber tires are discarded annually. A long time is needed for them to degrade naturally. This poses two major problems: environmental pollution and wastage of valuable rubber. On the other hand, with the harm of vibration and noise widely recognized, desires to control them intensify. As an important means of vibration control, viscoelastic damping technology has advanced greatly. The need for cheap and high quality viscoelastic damping materials increases rapidly. This paper made a trial to use ground rubber tire (GRT) recovered from old tires to make damping materials. The GRT is treated specially first. Then it was pressed into slabs and vulcanized. Finally, the product was cut into test samples. An Oberst beam was used to determine the loss factor βand storage modulus E. Results show that the damping materials exhibit good damping α-bility.

Mechanical behavior of entangled metallic wire materials-polyurethane interpenetrating composites

Composite materials exhibit the impressive mechanical properties of high damping and stiffness,which cannot be attained by employing conventional single materials.Along these lines,a novel material architecture is presented in this work in order to fabricate composites with enhanced mechanical characteristics.More specifically,entangled metallic wire materials were used as the active matrix,whereas polyurethane was employed as the reinforcement elements.As a result,an entangled metallic wire material-polyurethane composite with high damping and stiffness was prepared by enforcing the vacuum infiltration method.On top of that,the mechanical properties(loss factor,energy consumption,and average stiffness)of the proposed composite materials were characterized by performing dynamic tests,and its fatigue characteristics were verified by the micro-interface bonding,as well as the macro-damage factor.The impact of the density,preloading spacing,loading amplitude,and exciting frequency on the mechanical properties of the composites were also thoroughly analyzed.The extracted results indicate that the mechanical properties of the composites were significantly enhanced than those of the pure materials due to the introduction of interface friction.Moreover,the average stiffness of the composites was about 10 times the respective value of the entangled metallic wire material.Interestingly,a rise in the loading period leads to some failure between the composite interfaces,which reduces the stiffness property but enhances the damping dissipation properties.Finally,a comprehensive dynamic mechanical model of the composites was established,while it was experimentally verified.The proposed composites possess higher damping features,i.e.,stiffness characteristics,and maintain better fatigue characteristics,which can broaden the application range of the composites.In addition,we provide a theoretical and experimental framework for the research and applications in the field of metal matrix composites.

Influence of Annealing Time on the Microstructure and Properties of Pb(Zr_(0.53)Ti_(0.47))O_3 Thin Films

The PZT thin films were prepared on （111）- Pt/Ti/SiO2/Si substrates by sol-gel method, and lead acetate [Pb（CH3COO）2], zirconium nitrate [Zr（NO3）4] were used as raw materials. The X-ray diffractometer （XRD） and scanning electron microscopy （SEM） were used to characterize the phase structure and surface morphology of the films annealed at 650 ~C but with different holding time. Ferroelectric and dielectric properties of the films were measured by the ferroelectric tester and the precision impedance analyzer, respectively. The PZT thin films were constructed with epoxy resin as a composite structure, and the damping properties of the composite were tested by dynamic mechanical analyzer （DMA）. The results show that the films annealed for 90 minutes present a dense and compact crystal arrangement on the surface; moreover, the films also achieve their best electric quality. At the same time, the largest damping loss factor of the composite constructed with the 90 mins-annealed film shows peak value of 0.9, hi^her than the pure epoxy resin.

Microstructure and Properties of SiC/Gr Composite Reinforced Aluminum Matrix Composites Material

SiC/Gr/ZL101 aluminum-based composites were prepared by semi-solid stirring and gravity pouring method. The effects of SiC/Gr with different volume fractions on the microstructure and property of aluminum-based composites were studied by means of microstructure observation, tensile test, fracture scanning analysis and damping capacity test. The results show that the primary phase α-Al of ZL101 alloy prepared by semi-solid stirring and gravity pouring method is fragmented dendrite, along with the rising SiC volume fractions, the tensile strength of the composites first increases and then decreases while its elongation gradually decreases, the maximum tensile strength of the material can reach 168 MPa, up to 16% than that of ZL101 alloy, the fracture morphology is obviously brittle fracture. They also show that the addition of SiC and Gr improves the damping capacity of ZL101 alloy, the internal dissipation Q^-1 of the composites is obviously higher than that of matrix alloy and gradually increases along with the rising SiC volume fractions. The damping mechanism of the composites is mainly the combined effects of both dislocation damping and interfacial damping.

Synthesis and Characterization of Polyurethane and Epoxy Resin Interpenetrating Polymer Network

A series of Polyurethane (PU)/bisphenol A based Epoxy Resin(EP) Interpenetrating Polymer Networks(IPN) were synthesized and characterized by SEM, DSC, TGA and DMTA. It was found that IPN shows the best compatibility and damping properties when the ratio of PU/EP is 80 to 20. The results show that chain-extender and higher molecular weight of PPG are able to improve the properties of compatibility, damping and thermal properties.