Wyniki wyszukiwania - BazTech

1

Rheological and mechanical behavior study of eco-friendly cement mortar made with marble powder

Chahour Kahina, Mechakra Hamza, Safi Brahim, Dehbi Nacera-Melissa, Chaibet Cylia

International Journal of Applied Mechanics and Engineering

|

2024

|

Vol. 29, no. 1

19--35

EN

The work aim is to investigate the rheological and mechanical behavior of eco-friendly mortar made with marble powder. Marble have used as sand by total substitution of natural sand and as additional materials by partial substitution of cement. Firstly, rheological tests were carried out on the cement pastes in order to studying the effect of cement substitution by marble powder on the rheological behavior. Secondly, our study is devoted to evaluate the mechanical performances (flexural strength, compressive strength, mechanical behavior and ultrasonic pulse velocity) of a fluid mortar such as the case of the self-compacting mortars elaborated with the marble powder as addition materials and as a sand. The mechanical test results show that a significantly improved of compressive strength and mechanical behavior of an ecological cement mortar made with marble waste as a natural sand. However, marble-based mortars with 100% of marble sand have given a mechanical strength similar to that obtained by control cement mortar (100% natural sand). It was also noted that it can be obtained an ecological cement mortar made with 30% of marble powder as an addition supplementary materials. This leads to a reduction in cement consumption cad a reduction in CO2 gas emissions caused by cement production.

2

Mechanical behavior of adhesive joints : a review on modeling techniques

Ries Maximilian

Computer Methods in Materials Science

|

2024

|

Vol. 24, No. 4

5--35

EN

In the pursuit of lighter designs, many industries are shifting from conventional fasteners to adhesive joints, which offer a better strength-to-weight ratio and facilitate the use of fiber-reinforced polymers. However, modeling adhesive joints presents major challenges due to the complex behavior of polymeric adhesives and the microstructural changes induced by the substrates. As a result, various simulation methods have been developed to capture the behavior of adhesive joints across different scales. Molecular dynamics studies address atomistic and nanoscale phenomena, while continuum approaches – such as the finite element method, cohesive zone models, and peridynamics - focus on meso and macro scales. Additionally, multiscale methods combine particle and continuum approaches to provide a more comprehensive understanding of the adhesive bond behavior. This review paper offers an overview of the most relevant numerical methods employed to examine the mechanical behavior of adhesive joints and illustrates the simulations’ applications through examples from the literature.

3

Experimental investigation into the properties of crumb rubberized concrete incorporating corrugated round steel fibers

Ghoniem Amr, Aboul Nour Louay

Archives of Civil and Mechanical Engineering

|

2024

|

Vol. 24, no. 2

art. no. e100, 2024

EN

This paper presents an experimental study on how crumb rubber particles from waste tires and corrugated round steel fibers affect the mechanical behavior of concrete. In addition to the standard plain mix and five combinations of mixes composed of 0.5%, 1.0%, and 1.5% ratios, three steel fiber and crumb rubber mixes, 0.5%, 1.0%, and 2.0% weight of sand, coarse aggregate, cement, and silica fume were evaluated. The percentage of silica fume that replaced the weight of the cement in this study was 8%. The fresh properties of the 12 mixtures in terms of slump and density were studied. After 28 days of curing 36 cubes, 36 cylinders, and 12 prisms, the hardened properties were determined by evaluating the mean compressive, split, and flexural strengths. The results indicate that a synergetic effect is observed for the combination of crumb rubber and corrugated round steel fibers to improve the fresh and hardened properties of concrete. Adding fiber reinforcement to concrete can mitigate the negative impacts of rubber, and vice versa. According to the combination content, increases in compressive strength, tensile strength, and flexural strength of up to 49.04%, 38.60%, and 75.76%, respectively, were achieved compared with the control combination. This validates the applicability of the proposed mathematical prediction formulation to evaluate the compressive strength, split tensile strength, and modulus of rupture of rubberized fibrous concrete in terms of fiber and rubber ratios. Based on these results, a promising solution for tire disposal is to recycle waste rubber for fibrous concrete applications.

4

Comparison and study of mechanical and physical properties of metakaolin reinforced gypsum composite

Moradi Hossein, Azima Saba, Ebrahimi-Kahrizsangi Reza

Composites Theory and Practice

|

2023

|

R. 23, nr 3

129--135

EN

This study investigated the effect of creating a composite of gypsum with metakaolin as well as the physical and mechanical behavior of the produced composites. For this purpose, gypsum composites were prepared with 2.9, 4.8, 6.5, and 9 wt.% metakaolin in 100 g of gypsum and a constant content of water. To determine the mechanical properties of the composites, the compressive strength test was used and the porosity, water absorption percentage, and bulk density of the composites were obtained using the Archimedes method. The results showed that the porosity was reduced by adding up to 7 wt.% metakaolin to the gypsum specimens, it increases the compressive strength by 41% and also raises the Young’s modulus of gypsum by 121%. Scanning electron microscopy (SEM) equipped with energy-dispersive X-ray spectroscopy (EDS) was employed for the microstructural evaluations. The EDS-SEM observations showed the presence of Al and Si elements in the fracture zones. The presence of metakaolin elements at one point increases resistance in that area. Metakaolin-reinforced gypsum composites can be used in boards and panels.

5

Research on Mechanical Properties of Carbon Nanotubes (CNTs) Reinforced Cast Aluminum Alloy (ZL105)

Pan Zhilin, Li Rong, Zeng Qi

Archives of Metallurgy and Materials

|

2023

|

Vol. 68, iss. 4

1307--1318

EN

In order to expand the application range of casting aluminum alloy ZL105, the stirring fusion casting method was used to add carbon nanotubes (CNTs) with different content and aspect ratio into the ZL105 aluminum matrix. And then the effect of the reinforcement on the mechanical properties of the alloy was compared and analyzed. The research results show that the tensile strength and hardness of the carbon nanotube composites with different contents will be improved, but to a certain extent the elongation of the composite material will be reduced, and there is an optimal addition amount. The mechanical properties of composite materials prepared by adding CNTs with relatively small length and diameter are better. There are different forms of reinforcement mechanisms for CNTs to reinforce cast aluminum alloys, and the improvement of composite material performance is the result of the combined effect of multiple strengthening methods. The research has made a meaningful exploration for the realization of carbon nanotube reinforced aluminum matrix composites under the casting method.

6

Mechanical Properties, Machinability and Corrosion Resistance of Zamak5 Alloyed by Copper

Al Aboushi Ahmad, Al-Qawabah Safwan, Abu Shaban Nabeel, Al-Rawajfeh Aiman Eid

Archives of Metallurgy and Materials

|

2023

|

Vol. 68, iss. 4

1391--1399

EN

Due the importance of using commercially Zamak5 in a wide range in industrial applications, however, this study was focused on the enhancing its machining issues by adding pure copper, so the effect of the addition of (1 to 3)% Cu to commercially Zamak5 on its mechanical properties, microhardness, surface texture and corrosion resistance was investigated. A CNC machining tests, microhardness tests, corrosion test, compression test, and microhardness test were performed. It was found that there is an enhancement on the flow stress at 0.2 strain of about 19% for 3% Cu addition followed by 17% and 15% in the case of 2% Cu and 1% Cu respectively. There was an enhancement in microhardness of about 11.6% in the case of 3% Cu addition. The surface finish was improved by increasing the number of copper contents (1 to 3)% to the base material Za5. Polarization measurements revealed that 3% alloy specimen inhibit the corrosion by more than 70% compared with the blank sample.

7

Mechanical properties of CFST short columns with different void ratios

Song Junxi, Han Zhuowei, Wang Dawei, Lu Xiaorui

Archives of Civil Engineering

|

2023

|

Vol. 69, nr 3

587--596

EN

In order to study the mechanical behavior of concrete-filled steel tube(CFST) short column with different void ratios under a certain eccentricity. A fiber model of concrete-filled steel tube section with different void heights was established. Compared with existing model test data, the axial force and flexural moment strength models of concrete-filled steel tube columns with different void ratios were established. The results show that, in the case of different void ratios, the cross-section strength envelope shows an overall contraction tendency with the increase of void ratio, and each line is basically parallel. A model for calculating the coefficient of axial load degradation was established. The Han’s flexural moment strength model of the flexural component was revised, and the strength model of concrete-filled steel tube column under eccentric compression considering void ratio was established, which provides a theoretical basis and method for the safety assessment during the operation of concrete-filled steel tube arch bridges.

8

Mechanical behavior and constitutive model of lining concrete in triaxial compression infiltration process under pore water pressure

Xue Weipei, Jing Wei, Wang Zhongjian, Zhang Hanwen, Lin Jian

Archives of Civil and Mechanical Engineering

|

2023

|

Vol. 23, no. 1

art. no. e20, 2023

EN

Underground concrete structures are affected by groundwater, the effects of which are different from those of stress environments experienced by ground engineering concrete structures. This study experimentally and theoretically investigates the mechanical behavior, permeability evolution, and deformation failure mechanism of lining concrete under pore water pressure. Results show that an increase in pore water pressure promoted the coupling of seepage and stress fields in concrete. This caused the microcracks to propagate further, which led to a decrease in concrete strength and elastic modulus. Through triaxial compression infiltration, the concrete successively underwent initial compaction, linear elastic deformation, and nonlinear deformation after yielding. Accordingly, its permeability exhibited three trends: gradual decrease, stable development, and a sharp increase. The change in permeability was closely related to the number of pores and the development of microcracks in concrete. The concept of primary pore strain was proposed according to the characteristics of deformation and failure. Moreover, a triaxial compression infiltration constitutive model was derived for concrete based on the principle of effective stress. This model considers the influence of pore water pressure and the initial compaction characteristics. This study can be used to guide the design of lining concrete structures in underground engineering.

9

Investigation of the mechanical and hygrothermal behavior of coffee ground wastes valorized as a building material: analysis of mix designs performance and sorption curve linearization effect

Hamdaoui Mohamed Ali, Benzaama Mohammed-Hichem, El Mendili Yassine, Chateigner Daniel, Gascoin Stéphanie

Archives of Civil and Mechanical Engineering

|

2023

|

Vol. 23, no. 1

art. no. e57, 2023

EN

Coffee ground wastes (CGW) are by-products from the coffee-making processes. In this study, we propose to valorize them in construction materials at large scale. In particular, we investigate the mechanical and hygrothermal performances of earthen cob construction with incorporation of various amounts of CGW. Our results indicate that adding coffee grounds to cob enhances its hygrothermal performances as well as its compressive strength. An interesting enhancement of the lightened earth thermal characteristics as well as a good control of the hydric load in the air while maintaining acceptable mechanical properties is observed. Numerical analysis is used to evaluate the hygrothermal behavior of cob specimens to better understand their energy performances. A simplification of the simulation methods using a linearization of the sorption curve is incorporated to reduce calculation times and optimize outputs. The method is validated using experimental data, which shows a promising improvement compared to previous approaches. The proposed method can be faithfully applied to the study of hygrothermal behavior of biomaterials, which is strongly related to the building energy performance and the investigation of their durability in a fast and effcient way.

10

Experimental and numerical investigation of an arch-beam joint for an arch bridge

Yang Yan, Lin Benqing, Zhang Wei

Archives of Civil and Mechanical Engineering

|

2023

|

Vol. 23, no. 2

art. no. e101, 2023

EN

In this paper, the stress analysis of the most critical beam-arch joint of Yuehu Bridge is conducted, despite the variation in the specific structure of each tied arch bridge. To achieve this, two specimens with different scale ratios were designed. The smaller specimen was used to consider the effect of bridge deck and loading to failure. The experimental results indicate that both specimens did not exhibit significant deformation under the design load, and the measuring point’s stress was located in the elastic section. This implies that the original bridge structure design is rational. However, the arch rib steel plate of the 1/8 scale specimen buckled when subjected to 1.8 times the design load. To validate the experimental results, a finite element model that considers the elastoplastic behavior of the material was established and compared with the experimental results. The comparison shows that the finite element model can predict the mechanical behavior of the structure effectively, thus confirming the rationality of the structure design. Additionally, the study also analyzed the buckling problem of tied arch bridges, which is another critical issue. The in-plane and out-of-plane buckling of fixed and hinged parabolic arches under uniform axial compression were investigated. The results demonstrate that the boundary conditions, rise-span ratio, and bridge deck width significantly affect the buckling performance. Overall, this study provides essential insights into the stress and buckling behavior of tied arch bridges, which can guide the design and construction of such structures in the future.

11

Investigating the Effect of Photo-Oxidative Degradation on the Ageing Resistance of the Car Mudflaps Manufactured with Post-Production High-Density Polyethylene Wastes

Czarnecka-Komorowska Dorota, Swain Chandra, Kopeć Bogdan, Borowski Jacek, Garbacz Tomasz

Advances in Science and Technology. Research Journal

|

2022

|

Vol. 16, no. 4

38--47

EN

The paper presents the results of the ageing resistance of automotive mudflaps made of recycled polyethylene blends. The mudflaps were manufactured by a plastic sheet extrusion-calendaring process in Novotech Kostrzyn nad Odrą company. The changes of the mechanical properties in the tensile test and impact toughness test as well as in Shore hardness due to the accelerated aging process were characterized, taking into account the aging sensitivity coefficient (KI), and changes in the structure within the wavenumber range 4000-400 cm-1, taking into account the CI coefficient. The results showed a higher melting point and crystallinity for the recycled HDPE blends during photo-oxidative degradation. Moreover, the results presented decreased tensile strength and ductility, due to macromolecular chain scission caused by oxidation. It was found that the blends of HDPE based on recycled materials are more sensitive to the aging process than virgin HDPE. Finally, it can be concluded that the sensitivity to ageing blends increases with the increase of recycled HDPE content in the HDPE matrix.

12

Mechanical stability of retained austenite in aluminum-containing medium-Mn steel deformed at different temperatures

Kozłowska Aleksandra, Radwański Krzysztof, Matus Krzysztof, Samek Ludovic, Grajcar Adam

Archives of Civil and Mechanical Engineering

|

2021

|

Vol. 21, no. 1

324--338

EN

The thermal and mechanical stabilities of retained austenite in aluminum-containing medium-Mn 0.16C–4.7Mn–1.6Al–0.2Si sheet steel were investigated. The strain-induced martensitic transformation in Mn TRIP steel was studied at different temperatures. Static tensile tests were carried out at the temperature ranging from − 60 to 200 °C. The tests allowed to study the influence of the temperature on austenite-to-martensite transformation kinetics. The interrupted tensile tests and corresponding X-ray measurements of retained austenite amount were performed to determine the mechanical stability of retained austenite using the Sugimoto model. The microstructure changes were investigated using scanning electron microscopy (SEM), electron backscatter diffraction (EBSD), X-ray diffraction (XRD) and transmission electron microscopy (TEM) techniques. Observed results reflected the effects of deformation temperature on the mechanical stability of retained austenite and the corresponding response of this phase to martensitic transformation. It was found that an increase in the deformation temperature resulted in the reduced intensity of the TRIP effect due to the higher mechanical stability of retained austenite. At the highest deformation temperature (200 °C), the evidence of thermally activated processes affecting the mechanical behavior was identified.

13

Crack evolution and acoustic emission characteristics of rock specimens containing random joints under uniaxial compression

Ma Wenqiang, Wang Jiuting, Li Xiaoxiao, Wang Tongxu

Acta Geophysica

|

2021

|

Vol. 69, no. 6

2427--2441

EN

Joints greatly affect the mechanical behavior and crack evolution of jointed rock masses. In this paper, numerical specimens containing pre-existing random joints are constructed based on a combination of the fat-joint and smooth-joint models in the particle flow code in two dimensions (PFC2D). Then, uniaxial compression of these specimens is carried out to reveal the influence of joint length or number on the mechanical behavior, crack development, acoustic emission (AE) event attributes and failure characteristics. The results suggest that a univariant increase in random joint length or number leads to a nonlinear decrease in the uniaxial compressive strength (UCS) and a linear decrease in the elastic modulus, while the fracture behavior of the specimens shows a transformation from brittle to ductile in this process. With increasing joint length or number, the cracks and AE events generated in the joints significantly increase and exceed those generated in the intact rock. Tension cracks play a dominant role in the development of cracks within intact rock, while shear cracks dominate the crack evolution of random joints. More cracks appear in the jointed rock specimens at the elastic deformation stage as the joint length or number increases. The variation in the joint length or number strongly influences the mechanical behavior, crack evolution and failure pattern of the randomly jointed rock specimen.

14

Investigations on tensile and flexural characteristics of fly ash and banana fiber-rein

Gopalan Venkatachalam, Sharma Shashank Kumar, Jangid Anil Kumar, Pragasam Vignesh, Satonkar Nilesh, Chinnaiyan Pandivelan

Engineering Transactions

|

2020

|

Vol. 68, iss. 1

89--101

EN

Polymer matrix composites (PMCs) generally use the inorganic and non-biodegradable materials as reinforcements. This paper presents a PMC with reinforcement of fly ash and banana fiber. The epoxy resin is used as a matrix. This paper investigates the influences of the percentage of fly ash, the percentage of banana fiber and the size of banana fiber on tensile and flexural behaviors of fly ash and banana fiber reinforced epoxy matrix composite. Taguchi’s orthogonal array is used in the design of the experiments in the sample preparations. Analysis of variance (ANOVA) is employed to find the significance of input parameters on tensile and flexural behaviors.

15

Mechanical behavior around double circular openings in a jointed rock mass under uniaxial compression

Lin Qibin, Cao Ping, Cao Rihong, Lin Hang, Meng Jingjing

Archives of Civil and Mechanical Engineering

|

2020

|

Vol. 20, no. 1

264--281

EN

To better understand the mechanical behavior in a jointed rock mass, a series of uniaxial compression tests were conducted on non-persistently jointed rock specimens with double circular holes. Acoustic emission (AE) and digital image correlation (DIC) techniques were applied to capture micro-crack events and real-time strain field evolution in the specimens. The results indicate that the existence of non-persistent joints has a significant influence on the strength characteristics of the specimens. Specifically, peak strength decreases at first and reaches a minimum at 30° then increases with increase in the joint dip angle. DIC technology has successfully monitored the development of surface strain fields. The fracture evolution process is comprehensively understood. Every sudden change in a strain field is usually accompanied by apparent AE events and stress–strain curves take the form of oscillations. The crack coalescence modes among joints can be summarized as six types and the crack coalescence patterns around holes and joints can be divided into three categories. These results are helpful to understanding further the mechanical properties and fracture mechanism of openings in non-persistently jointed rock masses.

16

Experimental and numerical study of bead welding behavior of HDPE pipe under uniaxial loading

Belaziz Azzeddine, Mazari Mohamed

Mechanics and Mechanical Engineering

|

2019

|

Vol. 23, nr 1

183--191

EN

The present paper is devoted to the experimental study of the mechanical behavior of high-density polyethylene structure subjected to traction andwelded by means of butt-welding process. We were based ourselves on experimental testswhich have been carried out to characterize the material studied, introducing the ductility or fragility of the beadwelded section, and understood the effect of crosshead speeds on the mechanical behavior of the weld bead. The experimental results of the welded specimens are compared with those corresponding to the base material. In this study, two crosshead speeds of 10 and 50 mm/min were applied to make the comparison.

17

Vibration Control Devices for Building Structures and Installation Approach: a review

Sarwar Waseem, Sarwar Rehan

Civil and Environmental Engineering Reports

|

2019

|

Vol. 29, no. 2

74--100

EN

Retrofit and structural design with vibration control devices have been proven repeatedly to be feasible seismic hazard mitigation approach. To control the structural response; supplemental energy dissipation devices have been most commonly used for energy absorption. The passive control system has been successfully incorporated in mid to high rise buildings as an appropriate energy absorbing system to suppress seismic and wind-induced excitation. The considerable theses that are highlighted include vibration control devices, the dynamic behavior of devices; energy dissipation mechanism, devices installation approach and building guidelines for structural analysis and design employing vibration control devices also, design concern that is specific to building with vibration control devices. The following four types of supplemental damping devices have been investigated in this review: metallic devices, friction devices, viscous fluid devices, and viscoelastic devices. Although numerous devices installation techniques available, more precisely, devices installation approaches have been reviewed in this paper, including Analysis and Redesign approach (Lavan A/R), standard placement approach, simplified sequential search algorithm, and Takewaki approach.

18

Thermal damage of CFRP laminate in fiber laser cutting process and its impact on the mechanical behavior and strain distribution

Li Maojun, Gan Guocui, Zhang Yi, Yang Xujing

Archives of Civil and Mechanical Engineering

|

2019

|

Vol. 19, no. 4

1511--1522

EN

Fiber laser cutting is a promising alternative to the conventional methods in machining CFRP with high efficiency, while the influence of machined quality on strain distribution and mechanical behavior of CFRP laminates is yet not fully understand. The aim of this paper is to study the effect of laser cutting parameters on thermal defects and related mechanical performance. DIC technique was successfully employed to assess full-field strain distribution under tensile loading. The relationship between strain distribution and failure evolution/mode was also investigated. Results showed that various thermal defects including matrix recession, resin decomposition, fiber burrs and delamination were observed on entry and exit surfaces, while microcracks, cavities and striations were prevalent on machined surface. Tensile strength of CFRP laminate with open hole was highly related to applied laser processing parameters. DIC technique indicated that the crack propagation and failure mode were in good agreement with the high level of strains developed around the hole. Matrix-fiber interface cracking, fiber breakage and splitting were the main failure modes at test cessation.

19

Effect of High-Frequency Electric Resistance Welding (HF-ERW) Parameters on Metallurgical Transformations and Tensile Properties of API X52 Microalloy Steel Welding Joint

Sabzi M., Kianpour-Barjoie A., Ghobeiti-Hasab M., Dezfuli S. M.

Archives of Metallurgy and Materials

|

2018

|

Vol. 63, iss. 4

1693--1699

EN

This study investigates the effects of frequency, compression force and Vee angle parameters of High-Frequency Electric Resistance Welding (HF-ERW) process on mechanical properties of API X52 microalloy steel welding joint. Therefore, API X52 microalloy steel sheets having thickness of 8 mm was provided to manufacture pipes with the diameter of 16”. with direct weld seams using the HF-ERW method. During the manufacturing process, frequency values of 150, 200 and 250 kHz, compression forces of 2, 4 and 6 mark and Vee angles of 3°, 5°, and 7° were adopted. After changing the welding parameters, from the welded pipes, tensile and Charpy impact test samples prepared to macroscopically evaluate the weld metal flow and examine the effects of these parameters on mechanical properties of the welded joints. According to the results, it was concluded that frequency of 150 kHz, the compression force of 4 mark and Vee angle of 5° yields best mechanical properties in the HF-ERW joint of API X52 microalloy steel.

20

Structural optimization of internally reinforced beams subjected to uncoupled and coupled bending and torsion loadings for industrial applications

Silva H. M., Meireles J. F.

Mechanics and Mechanical Engineering

|

2017

|

Vol. 21, nr 3

731--753

EN

In this work, novel types of internally reinforced hollow-box beams were structurally optimized using a Finite Element Updating code built in MATLAB. In total, 24 different beams were optimized under uncoupled bending and torsion loads. A new objective function was defined in order to consider the balance between mass and deflection on relevant nodal points. New formulae were developed in order to assess the efficiency of the code and of the structures. The efficiency of the code is determined by comparing the Finite Element results of the optimized solutions using ANSYS with the initial solutions. It was concluded that the optimization algorithm, built in Sequential Quadratic Programming (SQP) allowed to improve the effective mechanical behavior under bending in 8500%, showing a much better behavior than under torsion loadings. Therefore, the developed algorithm is effective in optimizing the novel FEM models under the studied conditions.