Physical Parameters Of Materials Research Articles

ИССЛЕДОВАНИЕ ФИЗИКО-ХИМИЧЕСКИХ ЗАВИСИМОСТЕЙ В СИСТЕМЕ КОМПОЗИТА НА ОСНОВЕ ПОЛИУРЕТАНА, АРМИРОВАННОГО ПЛАЗМООБРАБОТАННЫМ БАЗАЛЬТОВЫМ ВОЛОКНОМ

Studies of physical and chemical properties of polymer composite material reinforced with basalt fiber have been carried out. Cast polyurethane based on SKU-PFL-100 prepolymer was used as a polymer. When evaluating the influence of the degree of basalt fiber filling on the complex of physical and mechanical parameters of the polymer composite material, it was revealed that the tensile strength increases up to 10 wt % reinforcement compared to the unfilled analog. Exposure of the basalt fiber to high-frequency plasma of reduced pressure had an effect on the increase of adhesion in the polymer-fiber system. The study of adhesion interaction between fiber and polymer matrix by pulling polyurethane basalt fibers woven into a bundle revealed that the value of applied load increased by 25 %. It is revealed that the best performance was achieved when reinforcing polyurethane with basalt fiber in the amount of 1 wt % - the tensile strength of the material increased by 60 % for samples with fiber preplasma treatment and by 30 % for samples with basalt fiber without preplasma treatment.

Effectiveness of Laser-Assisted Teeth Bleaching: A Systematic Review

Objective: Esthetic dentistry is an important factor in increasing patients’ quality of life. This study aimed to investigate the impact of laser use on bleaching procedures for natural teeth and dental restorative materials. Methods: In January 2024, an electronic search was conducted using PubMed, Web of Science (WoS), and Scopus databases with the keywords (tooth) AND (laser) AND (bleaching), following PRISMA guidelines and the PICO framework. The initial search yielded 852 articles, of which 441 were screened. After applying inclusion criteria, 376 articles were excluded as they did not focus on the use of lasers in bleaching natural teeth and restorative materials. Consequently, 40 articles were included in the final review. Results: Of the 40 qualified publications, 29 utilized a diode laser, of which 10 authors concluded that it increases the whitening effect comparing classical methods. Three of included publications investigated the whitening of dental materials, while another three focused on endodontically treated teeth. Whitening procedures on ceramics effectively removed discoloration, but the resulting color did not significantly differ from the initial shade. Conversely, composite materials not only failed to bleach but also exhibited altered physical properties, thereby increasing their susceptibility to further discoloration. The KTP laser demonstrated promising outcomes on specific stains. The Er,Cr:YSGG and Er:YAG lasers also showed beneficial effects, although there were variations in their efficacy and required activation times. Conclusions: The findings partially indicate that laser-assisted bleaching improves the whitening of natural teeth. Further research on the effect of laser bleaching on the physical parameters of restorative materials is necessary.

Development of the algorithm for determining the thickness of the structural layers of the non-rigid pavement and searching for local inclusions using sub-surface georadiolocation methods

Problem. The article is part of the authors' research in the field of road construction using GPR technologies. Ensuring a certain level of pavement reliability on highways requires the development of methods and means for continuous information acquisition and processing in real time, taking into account the parameters of structural heterogeneity, heterogeneity of physical and mechanical parameters of structures, as well as their changes over time. The solution of this problem is limited by the complexity of tasks of obtaining and interpreting the data of subsurface sensing and the associated errors in determining the parameters of structures, imperfection of methods of flaw detection of structures with subsurface inhomogeneities, multifactorial tasks of estimation of physical and mechanical parameters of multicomponent materials. Goal. Improving the accuracy and reliability of determining the boundaries of layers of non-rigid pavement structure, which have a low level of electrodynamic contrast due to interpenetration of layer materials or changes in their physical and mechanical properties. The solution of this problem is connected with the development of a method of obtaining reflected GPR signals and the improvement of algorithms for their processing. Methodology. The development of methods for the analysis of the electromagnetic field with a variable state of polarization makes it possible to assess the localization of violations of the integrity of the pavement structure at a qualitatively new level and allows the positioning of small inclusions even with a slight contrast in the dielectric constant. The proposed method of recording the reflection of an ultra-wideband GPR pulse signal at different polarizations is implemented by measuring the reflected signal from a metal sheet at oblique incidence and parallel polarization, recording the reflected pulse at perpendicular polarization, followed by measuring the reflection coefficient from the structure of the nonrigid pavement under study at parallel and perpendicular polarization. The electrophysical parameter recovery procedure is based on the solution of inverse scattering problems and ensures the accuracy of determining the low-contrast boundaries of the pavement structure and increases the accuracy of positioning subsurface heterogeneities. GPR signal processing algorithms are based on procedures for analyzing their polarization state, which allows determining the geometric parameters of subsurface heterogeneities. Practical value. The combination of the obtained results increases the accuracy and reliability of the results of GPR diagnosis and assessment of the condition of non-rigid pavement based on the most complete and reliable information about the subsu

Comparative Investigation of Pressure Effect on Structural Stability, Electronic and Optical Response of LaXO<sub>3</sub> (X = Al, In, Ga) for Optoelectronic Applications

A first principle study intense on the density functional theory with Heydscuseria-Ernzerhof screened hybrid functional hybrid function (HSEO6) is used to assess the structural, Electronic, elastic, mechanical and optical responses of LaXO<sub>3</sub> (X = Al, In, Ga) perovskite materials. The compressive investigation under the external static isotropic pressure (P= 0 to 80GaP), phase stability, band structure and their important impact on the optical response of LaAlO<sub>3</sub>, LaInO<sub>3</sub> and LaGaO<sub>3</sub>. Electronic band structure shows that LaXO<sub>3</sub> (X = Al, In Ga) semiconductor with indirect band gap and an optically inactive response up to 20GPa, while the band gap becomes direct at 80GaP. There are gamma points (G-X-Q) at 80GPa and the band gap changes from indirect to direct nature. Under main desperation physical parameters of perovskite materials are well explained the response of TDOS, PDOS and EPDOS contour plots have been well understood for the full description of the band gap. It is further observed that the external pressure enhanced upto 40GPa both materials are significantly more mechanically stable compared to pristine LaXO<sub>3</sub> (X = Al, In, Ga) at 0GPa. The optical properties of LaAlO<sub>3</sub>, LaGaO<sub>3 </sub>and LaInO<sub>3</sub>, dielectric coefficient <i>(ε<sub>1</sub>, iε<sub>2</sub>)</i> have been employed along with the optical responses like absorption, energy loss function, reflectivity and reflective index are obtained in the energy scale from 0 to 60 eV. It was observed that static dielectric constant decreases with the decrease in optical band gap. The optical tunings under the effect of pressure which are good candidates in practical optoelectronic applications are extensively used and interpreted by the calculation of the dielectric function.

Parameter influence analysis of stochastic resonance and stochastic P-bifurcation for the shape-memory alloy laminate

This paper investigates the transverse vibration of an axially moving shape-memory alloy (SMA) fiber hybrid laminations under the combined action of transverse harmonic excitation and stochastic disturbance. Considering the shape memory alloy (SMA) fiber volume fraction random field, the kinetic energy and strain potential energy of SMA laminates are solved, and the axial motion equation of SMA laminates is derived according to Hamilton principle, a non-dimensional differential equation of the transverse vibration of the axially moving SMA laminated plates is obtained by adopting the Galerkin integral method. Considering the volume-fraction stochastic field, the stochastic natural vibration of a SMA laminate is analyzed. Considering the stochastic resonance of the SMA laminate under the action of Gaussian white noise and harmonic excitation, the effects of geometric parameters, physical parameters of materials, and temperature on the stochastic resonance behavior of the SMA laminate is analyzed. Finally, the effect of the stochastic P-bifurcation phenomenon of the parameters on the steady-state response of the SMA laminate is analyzed.

Electromechanical Device for Determining and Controlling Physical and Mechanical Parameters of Fiber Materials

Electromechanical Device for Determining and Controlling Physical and Mechanical Parameters of Fiber Materials

СПОСОБ ПРИДАНИЯ АНТИСТАТИЧЕСКИХ СВОЙСТВ ИЗОЛИРУЮЩЕМУ МАТЕРИАЛУ УНКЛ-3

The subsystem for protection from static electricity of personnel wearing personal protective equipment (PPE) shall ensure safe operation of the technological line of disassembly and destruction (TL DD) in all its modes of operation, as well as to eliminate the possibility of an emergency situation due to the accumulation of static electricity charges on PPE during operation, to reduce the level of electrification on PPE, adversely affecting the technological process and product quality. The work on reduction of electrification of insulating material UNKL-3 of L-1 suit for special works was carried out. Literature review of existing technical solutions for protection against static electricity accumulation on the surface of polymers used in chemical industries was carried out. On the basis of literature data and conducted experiments an effective surface-active substance, antistatic agent Alkapav was chosen. It is well sorbed by polymeric materials on the basis of butyl rubber, so it is evenly distributed on the surface of the L-1 suit. Physical and mechanical parameters of UNKL-3 material after treatment with Alkapav antistatic agent remain unchanged. The results of the conducted research allow us to consider that the materials of L-1 suits after treatment with 10% aqueous solution of the selected antistatic agent Alkapav and subsequent operational tests do not exceed the value of specific surface electrical resistance (SSER) 1,0-109 Ohm, i.e. the indicators meet the requirements of GOST 12.4.124-83.

Ensuring the Safety of Buildings and Structures Damaged as a Result of Military Man-Made Actions

A significant number of destroyed buildings and structures during the military aggression of the Russian Fed-eration in Ukraine make it necessary for scientific organizations to solve new problems in the restoration of residential and public buildings. After explosive devices have hit the building, the first task is to identify the possibility of its further operation. Technical assessment of the damage level should be justified by using ex-perimental data on changes in the physical and mechanical parameters of construction materials and structures, which are strength, deformability, crack resistance, etc., as a result of the blast waves and fires that accompany explosions in the premises. An urgent task is to develop a methodology that takes into account the impact of explosions and fires caused by them so that structures can be calculated and their residual life estimated. For many decades, the State Research Institute of Building Constructions has been solving problems of assessing the technical condition of damaged buildings and structures as a result of man-made disasters and actions, fol-lowed by the development of technical solutions that ensure the necessary operational characteristics of these objects can be restored.

Calculating permissible deviations of vibration accelerations of printed circuit assemblies by simulation modeling

Objectives. A variety of technical condition control methods are used in the production and operation of printed circuit assemblies (PCA) for radio-electronic means (REM). The main methods are optical, electrical, and thermal. However, not all possible defects can be detected using these methods. For example, a weakened PCA fastener in a block or the incorrect installation of an electric radioelement (ERE) on a printed circuit board (PCB) can be detected only by analyzing the mechanical characteristics of the REM. These factors, in particular, are the values of the vibration acceleration amplitudes on ERE or at selected PCB control points (hereinafter referred to as the PCA vibration acceleration amplitude). In order to draw a conclusion about the presence of a defect, the measured values of the vibration acceleration amplitudes obtained as a result of testing PCA for the effects of harmonic vibration are compared with the permissible values calculated during the simulation of mechanical processes in PCA. This takes into account the variations in the physical and mechanical parameters of materials and geometric parameters of the PCA design. The aim of this paper is to determine the permissible values of PCA vibration acceleration amplitudes to be compared with the measured values.Methods. The Monte Carlo simulation method is used to calculate the permissible deviations of vibration accelerations. This consists in repeatedly calculating the values of the vibration acceleration amplitudes at random values of the physical and mechanical parameters of materials and geometric parameters of the PCA design within their tolerances.Results. Experimental verification of this method was carried out using the SolidWorks software for modeling mechanical processes. This enabled the tolerance values for PCA vibration acceleration at the control point at the first resonant frequency to be established and experimental data to be obtained when introducing various defects. The results of comparing the measured values with the calculated tolerance enabled conclusions to be made with regard to the possibility of detecting PCA defects.Conclusions. Using this method of calculating tolerances for the PCA vibration acceleration amplitude allows the presence of defects in REM that do not affect the electrical or thermal characteristics of REM to be determined, thus increasing the efficiency of technical condition control.

A review of soil pollution from LDPE mulching films and the consequences of the substitute biodegradable plastic on soil health

The plastic film mulching system has a significant role in increasing crop grain yields by changing the microenvironment of the plant. On the other hand, plastic mulching materials pollute the land and water because they are not degraded or disposed of properly. Biodegradable plastic mulches (BPM) may be used as a substitute for conventional low-density polyethylene (LDPE) to protect soil health. In this review, the effect of micro(nano)plastics on soil health and function has been discussed in light of their distribution in soil, changes in soil biochemistry, interactions between microplastics with soil microbes and plants, and their growth patterns. The nano-plastics are now incorporated into the food chain from the soil through plants and finally harm the whole ecosystem, including humans. The use of BPM has been practiced recently, but only 1% of the world’s total plastic production is from biodegradable materials. In the second part of the review, the confusing terms "bio-based" and "biodegradable" were clarified based on their polymeric constituents. The physical parameters of different constituent materials for mulching purposes and their capability for sustainable solarization have been discussed. The effect of biodegradable mulches on soil health and other ecotoxic effects on plants, soil microorganisms, and other soil dwellers like Daphnia magna, Vibrio fischeri bacteria, green algae, slime mould, protozoa, invertebrates like earthworms, and common water fleas have been focused on in this review. In conclusion, the use of BPM for mulching purposes was reported to improve crop quality and yield and reduce weed growth in comparison to naked soil. The recent short-term studies ensured that mulches stayed unbroken throughout the growing season. But simultaneously, the biodegradable mulches affect soil health and have a substantial impact on physical parameters such as soil pH, electrical conductivity, aggregate stability, infiltration, nitrate-N, exchangeable potassium, etc. Therefore, a lot of long-term research is required for the use of BPM as a substitute for conventional LDPE as a mulching film in the agricultural field.

Comparative assessment of physical and mechanical parameters of cast plastic material for the manufacture of bases of combined removable orthopedic structures

The urgent task of orthopedic dentistry is the timely and optimal restoration of chewing efficiency, with the creation of new and improvement of existing structural materials, optimization of the use of consumables and improvement of the clinical and technological stages of the manufacture of removable orthopedic structures. The purpose of our study was a comparative assessment of the physical and mechanical properties of cast plastic material for the manufacture of bases of combined removable orthopedic structures using an improved method. We have developed a new domestic material for the manufacture of the bases of removable dentures using foundry compression pressing technology. The following parameters of the study of physical and mechanical properties of plastics were taken into account: material Shore hardness, material consistency, relative deformation during compression, sorption, impact strength, bending stress, tensile strength, abrasion resistance, percentage of residual monomer. The comparative characterization of the physical and mechanical properties of cold polymerization acrylic plastics showed that domestic cold-cured base plastic for casting compression molding is not inferior to the foreign base in terms of its main indicators cold-hardening plastic differs from the analog cold-hardening base plastic by a harder and harder consistency, which makes it possible to more effectively use the material for combined bases of removable dentures. The obtained data indicate that, in general, the domestic material with its physical and mechanical properties meets the requirements for this class of dental materials. Keywords: orthopedic treatment, physical and mechanical properties, cast plastic material, method of compression pressing.

Seismic performance analysis of orthotropic shear walls based on the deformation energy decomposition method

Based on orthogonal completeness and mechanical equilibrium, the physical parameters of materials are further considered, and the deformation decomposition method is improved and applied to orthotropic structures. The method is realized by compiling ANSYS-MATLAB computer algorithms, and verified by strain energy analysis and experimental results. It not only quantitatively identifies tensile, compressive, bending and shear deformation energies of orthotropic structures, but also visualizes the regions dominated by the aforementioned fundamental deformation energies. Furthermore, the influence of the horizontal and vertical elastic modulus ratios of coupling beams and wall-columns on the seismic performance of orthotropic shear walls with different opening sizes is discussed. The results show that the ductility of the coupling beam and the wall-column is improved by appropriately reducing the horizontal and vertical elastic modulus ratio of the coupling beam, and the effect on the wall-column is weakened with the reduction of the opening size. But the lateral resistance of the shear wall is weakened. The wall-column ductility is improved by properly increasing the horizontal and vertical elastic modulus ratio of the wall-column, but the lateral resistance of the shear wall is weakened.

Calibration and verification of DEM parameters of wet-sticky feed raw materials

In order to improve the accuracy of the parameters needed in the discrete element method (DEM) simulation process of wet-sticky feed raw materials, the JKR contact model in DEM was used to calibrate and verify the physical parameters of wet-sticky feed raw materials. Firstly, the parameters that have a significant effect on the angle of repose were screened using a Plackett–Burman design, and the screened parameters were: MM rolling friction coefficient, MM static friction coefficient, and JKR surface energy. Then, the three screened parameters were selected as the influencing factors and the accumulation angle of repose was selected as evaluating indicator; thus, the performance optimization experiments were carried out with the quadratic orthogonal rotation design. Taking the experimentally measured angle of repose value of 54.25°as the target value, the significance parameters were optimized, and the optimal combination was obtained : MM rolling friction factor was 0.21, MM static friction factor was 0.51, and JKR surface energy was 0.65. Finally, the angle of repose and SPP tests were compared under the calibrated parameters. The results showed that the relative error of experimental and simulated tests in angle of repose was 0.57%, and the compression displacement and compression ratio of the experimental and simulated tests in SPP were 1.01% and 0.95%, respectively, which improved the reliability of the simulated results. The research findings provide a reference basis for simulation study and optimal design of related equipment for feed raw materials.

Classification of dissolution modes of partially protected poly(4-hydroxystyrene) in tetraalkylammonium hydroxide aqueous solutions

The development of high-numerical aperture exposure tools for EUV lithography is in progress. The development process (the dissolution of resist films) is the key to fine patterning. The dissolution dynamics of acidic polymers (the backbone polymers of chemically amplified resists) depend on various parameters related to molecular structures. In this study, the dissolution dynamics in tetraalkylammonium hydroxide (TAAH) aqueous solutions were classified into six classes on the basis of the frequency and impedance changes observed during the development process by a quartz crystal microbalance method. The relationship between class and physical parameters of materials was analyzed by decision tree and support vector machine methods. The feature values used were the alkyl chain length, molecular weight, and concentration of TAAH; the viscosity of the developer; and the protection ratio, molecular weight, contact angle, surface free energies of polymers, and film thickness. The classification accuracy was 0.80 for the validation data.

TCAD Device Simulation of All-Polymer Solar Cells for Indoor Applications: Potential for Tandem vs. Single Junction Cells.

The utilization of indoor photovoltaics makes it feasible to harvest energy from artificial light sources. Although single-junction indoor photovoltaics have demonstrated exceptional efficacy when using LED lighting, there is still a need for more comprehensive testing of tandem structures. Herein, the first systematic TCAD simulation study on the potential for tandem all-polymer solar cells (all-PSCs) for indoor applications is provided. The presented all-PSCs are based on experimental work in which the top wide bandgap subcell comprises a polymer blend PM7:PIDT, while the bottom narrow bandgap subcell has a polymer blend PM6:PY-IT. Standalone and tandem cells are simulated under AM1.5G solar radiation, and the simulation results are compared with measurements to calibrate the physical models and material parameters revealing PCE values of 10.11%, 16.50%, and 17.58% for the front, rear, and tandem cells, respectively. Next, we assessed the performance characteristics of the three cells under a white LED environment for different color temperatures and light intensities. The results showed a superior performance of the front cell, while a deterioration in the performance was observed for the tandem cell, reflecting in a lower PCE of 16.22% at a color temperature of 2900 K. Thus, an optimized tandem for outdoor applications was not suitable for indoor conditions. In order to alleviate this issue, we propose designing the tandem for indoor lightening by an appropriate choice of thicknesses of the top and bottom absorber layers in order to achieve the current matching point. Reducing the top absorber thickness while slightly increasing the bottom thickness resulted in a higher PCE of 27.80% at 2900 K.

Thickness Measurement of Self-Lubricating Fabric Liner of Inner Ring of Sliding Bearings Using Spectral-Domain Optical Coherence Tomography

This study presents a novel and highly accurate method of measuring the geometric thickness of the self-lubricating fabric liner of bearings by combining the optical coherence tomography (OCT) technology and the Hanning-windowed energy centrobaric method (HnWECM). The geometric thickness of wear-resistant coating material is one of the important indicators for evaluating its wear, and the measurement of its geometric thickness is of great significance for preventing coating failure. To address the issue of significant measurement errors caused by using the refractive index of the sample instead of the group refractive index to calculate the material’s geometrical thickness in previous OCT research and applications, our proposed method can accurately measure the geometrical thickness of materials without the influence of the refractive index of the material. Moreover, this method exhibits the advantages of non-contact and high precision, since it utilizes an SD-OCT system, making it a novel method for extracting the physical parameters of composite materials. The geometric thickness of the peeled-off liner obtained from our method is compared with the thickness measured by the spiral micrometer to evaluate its accuracy. The experimental results indicate that the thickness measured by the spiral micrometer was 172 μm, while the maximum difference in the data obtained by our method was 171.261 μm. This suggests that the difference between the two methods is less than 0.430%, which verifies the accuracy and validity of our method. Additionally, the obtained geometric thickness and the optical thickness of the peeled-off liner are used to evaluate the group refractive index of this material. The inside geometrical structure of the self-lubricating fabric liner on the end face and inner ring of the sliding bearing is imaged with this group refractive index. The measurement of the inner ring liner of the sliding bearing proves the flexibility of the fiber-optic OCT and provides a non-contact, nondestructive testing method for measuring the geometric thickness and internal geometric structure of composite materials.

Thermomechanical instability of viscoelastic friction materials in automotive disk clutches and brake pads

The objective of this study is to develop a mathematical model to aid in predicting the onset of instability in automotive disk brakes and clutches when using viscoelastic friction materials. The model is derived from and expands upon the fundamental of Burton’s model for thermoelasticity in pure elastic materials. In this investigation, three physical material parameters are considered: relaxation time, elasticity, and thermal conductivity. Prior to this parametric study, the effects of these material properties in relation to thermoelasticity were yet to be fully understood. Therefore, a finite element analysis is developed and used to validate the mathematical model by comparing the variation of the critical speed as a function of thermal conductivity. The results reveal that an increase in the relaxation time significantly reduces the critical sliding speed. Changing the elastic parameter further increases the effect of relaxation time by also reducing the critical sliding speed. However, increasing the thermal conductivity parameter dampens the effect of the elastic parameter and relaxation time on the critical speed. The study concludes there is a critical value of the relaxation time and elastic parameter above which the system stability is improved, meanwhile thermal conductivity attempts to counter the stability gained from other material properties. The study is instrumental in understanding the influence of viscoelastic parameters in sliding systems and provides an intuitive means of predicting the onset of thermomechanical instability.

The Historic Materials and Structures Due to the Aspect of Their Actual Challenges

The subject of the article is to assess the suitability of over materials over a hundred years old that are embedded in historic building structures in conditions of contemporary utility challenges in residential and public buildings. It is based on an example of technical condition evaluation of a ceramic staircase erected in 1840 and a structure of two reinforced concrete staircases from the year 1910. As a part of in-situ and laboratory tests, the physical and mechanical parameters of unique historical materials (brick, concrete) were determined. Then the conditions for their incorporation were inventoried and determined in order to save the unique material and technical solutions used in the first half of the 19th century and the first decade of the 20th century. The article is a summary of the research and analyzes carried out in terms of proper handling of historical materials, buildings and their elements that could still fulfill their original function and be a witness to the history of a certain era. Both a research case and an application case are described here. It will allow for the continuation of these studies directly in the facility, thus assessing the effectiveness and suitability of such methods for use in similar or other situations. The aim of this approach was to introduce a non-invasive reinforcing technique that would not change the valuable and authentic appearance of these historic structures. It would also not change their static schemes, and at the same time would ensure their proper load-bearing capacity, bearing in mind that the materials used here are not equivalent to current regulations and standards.

Axial crushing of circular thin-walled specimens made of CFRP using progressive failure model (MAT54) in LS-Dyna

This research focuses on calibrating the MAT54 (ENHANCED_COMPOSITE_DAMAGE) material card in LS-Dyna for simulating axial crushing of circular thin-walled specimens made of CFRP. An IM7/8552 composite specimen showing the layup sequence of [902/±452/02]2 was simulated in LS-Dyna using shell elements. Following a trial-and-error-based method, the physical and non-physical input material parameters of MAT54 were calibrated. The calibrated input parameters included material strengths, failure strains, softening factors, and damping coefficient. The results of this study showed the applicability of the use of the physical material inputs from material characterization tests (e.g., tensile, in-plane shear, and compression) while showing the necessity of more in-depth calibration processes for the non-physical material inputs (e.g., viscous damping coefficient, crashfront reduction algorithm, etc.). The initial model predicted the specific energy absorption with an error of −57.95 % and this was improved by the calibration process to an error equal to −1.49 % for the final model. Now validated, the model will be used in the future to simulate impact into composite vehicle armor.

Similar ratio experiment and characteristic analysis of quasi-sandstone

The stability control of surrounding rock in deep roadway is becoming more and more difficult, and grouting reinforcement support has become the mainstream of roadway control. In order to obtain the ratio of quasi-sandstone material corresponding to the grouting body, this paper uses river sand as aggregate, cement and gypsum as cementing agent, retarder and defoamer as additives, and carries out orthogonal proportioning tests with three influencing factors: water-binder ratio (ratio of water to mass of cementing agent), gypsum-cement ratio (ratio of gypsum to mass of cement) and binder-aggregate ratio (ratio of cementing agent to aggregate mass), and compares and analyzes the sensitivity of each factor on the density, compressive strength, tensile strength, elastic modulus, Poisson’s ratio, longitudinal wave velocity, elasticity index and brittleness index of quasi-sandstone material. The results show that 1) the Water-binder ratio has the greatest effect on the sensitivity of material compressive strength, tensile strength, elastic modulus, Poisson’s ratio and longitudinal wave velocity; the gypsum-cement ratio has the greatest effect on the sensitivity of material deformation index and brittleness index; the binder-aggregate ratio has the greatest effect on the sensitivity of material density. 2) Reducing the Water-binder ratio can improve the density, compressive strength and tensile strength of the material; reducing the paste ratio can improve the modulus of elasticity, Poisson’s ratio and longitudinal wave speed of the material; as the gypsum-cement ratio increases, the deformation index first decreases and then increases and then decreases; as the binder-aggregate ratio increases, the brittleness index first increases and then decreases and then increases. 3) The empirical equations between physical and mechanical properties of sandstone-like materials and Water-binder ratio, gypsum-cement ratio and binder-aggregate ratio were established based on multiple linear regression analysis, and more reasonable material ratios were quickly obtained by physical and mechanical parameters of materials. The results of the study provide theoretical references for similar material simulation tests for quasi-sandstone grouting.