Crack Development Research Articles

Deformation-fractional change in resistance model of SMA fiber reinforced mortar beams

Superelastic shape memory alloys (SMA) are metallic alloys that can enable components with self-recovery of cracks and deformation when combined with cement-based materials. Meanwhile, the monitoring method based on fractional change in resistance (FCR) can achieve self-monitoring of components throughout the entire loading process. In this study, the relationship between crack recovery characteristics and FCR of SMA fiber reinforced mortar beams subjected to flexural cyclic loading was analyzed. The beams with SMA fiber volume fractions of 0.1 %, 0.3 %, 0.5 %, and 1.0 % were tested under three-point bending loads. During the loading process, the FCR of the specimens were monitored by the four-electrode method. Finally, the deformation-FCR model for the whole process of the specimens was established to realize the real-time monitoring of the loading state of mortar beams. The results show that SMA fibers can enhance the flexural strength of mortar beams by a maximum of about 64 %, reduce residual deformation, and improve deformation self-recovery ability. The mid-span deflection recovery rate and crack size recovery rate generally increase with higher fiber volume fraction, which can maintain a better deformation recovery effect at the early stage of cracking and gradually decrease with the expansion of cracks. There is a close relationship between the FCR and the degree of crack development that the FCR increases with crack expansion and the magnitude of FCR decreases with increasing fiber content. The established first-order logarithmic fitting model can well describe the relationship between the FCR and cracking, which can provide reference for crack monitoring.

Study on the Development Rule of Mudstone Cracks in Open-Pit Mine Dumps Improved with Xanthan Gum

The stability of open-pit mine slopes is crucial for safety, especially for spoil dump slopes, which are prone to cracks leading to landslides. This study investigates the use of xanthan gum (XG) to enhance the stability of mudstone in spoil dumps. Various concentrations of xanthan gum were mixed with mudstone and subjected to dry–wet cycle tests to assess the impact on crack development. Pore and crack analysis system (PCAS) was utilized for image recognition and crack analysis, comparing the efficiency of crack rate and length modification. The study found that xanthan gum addition significantly improved mudstone’s resistance to crack development post-drying shrinkage. A 2% xanthan gum content reduced the mudstone crack rate by 45% on average, while 1.5% xanthan gum reduced crack length by 46.2% and crack width by 26.3%. Xanthan gum also influenced the fractal dimension and water retention of mudstone cracks. The optimal xanthan gum content for mudstone modification was identified as between 1.5% and 2%. Scanning electron microscopy imaging and X-ray diffraction tests supported the findings, indicating that xanthan gum modifies mudstone by encapsulation and penetration in wet conditions and matrix concentration and connection in dry conditions. These results are expected to aid in the development of crack prevention methods and engineering applications for open-pit mine spoil dump slopes.

Crack Development and Electrical Degradation in Chromium Thin Films Under Tensile Stress on PET Substrates

The mechanical and electrical deterioration of chromium (Cr) thin films sputtered onto polyethylene terephthalate (PET) substrates under tensile strain was studied. Understanding mechanical and electrical stability due to imposed strain is particularly important for device reliability, as the demand for flexible electronic devices increases. Cr thin films, widely spread across the field of electronic and sensor applications, face crack propagation with electrical degradation with tensile stress that can seriously compromise the performance. Accordingly, this study offers new findings on how Cr film thickness might influence crack formation and electrical resistance differently and also the general guidelines for flexible electronic component design with respect to long-term durability. Electrical resistances were measured while mechanically stretching 100- and 200 nm thin sheets. The study focused on crack development and propagation mechanisms in both film thicknesses and their effects on percentage change in electrical resistance (PCER). Scanning electronic microscopy (SEM) was used to characterize surface morphology and observe cracks as the strain rose. Early crack formation in 100 nm Cr films led to rapid PCER increases due to quick crack propagation and fast electrical degradation. Thicker 200 nm films, however, showed a more gradual PCER rise with fewer but deeper cracks, indicating a regulated strain response. Unlike the sharp PCER spike in 100 nm films, 200 nm samples were more variable, with three out of four showing a slight PCER decrease at the end, hinting at partial crack repair or conductive realignment before full failure. These results underscore the role of layer thickness in managing crack propagation and electrical stability, relevant for flexible electronics and strain sensors. This paper is aligned with the ninth goal of the United Nations Sustainable Development Goals, specifically Target 9.5: Enhance Research and Upgrade Industrial Technologies.

Numerical Simulation on the Influence of the Distribution Characteristics of Cracks and Solution Cavities on the Wellbore Stability in Carbonate Formation

The development of cracks and solution cavities in carbonate reservoirs can notably reduce the rock’s mechanical properties, leading to a severe wellbore collapse problem during drilling operations. To clarify the influence of the characteristics of cracks and solution cavities on the wellbore stability in the Dengying Formation carbonate reservoir in the Gaoshiti–Moxi area of Sichuan, the mechanical properties of carbonate rock were analyzed. Then, the influences of the attitude and width of cracks, the size and quantity of solution cavities, and their connectivity on wellbore stability were studied using FLAC3D 6.00 numerical simulation software. Our results show the following: (1) The cracks and solution cavities in the Dengying Formation carbonate rock cause significant differences in the rock’s mechanical properties. (2) The equivalent drilling fluid density of collapse pressure (ρc) considering the effects of cracks and solution cavities is 6.4% higher than without these effects, which is in good accordance with engineering practice. Additionally, cracks play a more significant role than solution cavities in affecting the wellbore stability. (3) When the orientation of a crack is closer to the direction of maximum horizontal stress, and the dip angle and width of the crack increase, the stress and deformation at the intersection of the crack and wellbore gradually increase, and correspondingly, ρc also increases. (4) The stress and displacement of various points around the solution cavities gradually increase with the increases in diameter and quantity of solution cavities, and ρc also increases. (5) Compared with the situation where cracks and solution cavities are not interconnected, the stress disturbance area around the wellbore is larger, and ρc is greater when cracks and solution cavities are interconnected.

Study on the deformation of hybrid BFRP-steel reinforced concrete beams considering crack development

Hybrid fiber-reinforced polymer (FRP)-steel reinforced concrete (RC) beams exhibit various flexural failure modes depending on different equal-stiffness reinforcement ratios, the post-yield stiffness ratio, and the bond-slip behavior. This study first develops a model for the tensile behavior of hybrid Basalt FRP (BFRP) -steel reinforced concrete chords, considering the modified Bertero-Popov-Eligehausen (mBPE) bond-slip model. The rationality of the tensile stiffening model was validated through comparisons with existing experimental tests on the axial tension of chords. Subsequently, a beam deformation correction calculation method considering ‘rigid-rotation’ was proposed. The corrected theoretical calculation of the beam’s peak load shows an error of 5.0% compared to the experimental value, while modified ultimate deformation exhibits an error of 4.7%. As the bond weakens, the theory proposed in this paper is more suitable for predicting the deformation capacity of hybrid reinforced beams. ACI 440.1R-15 underestimate deformations by approximately 77.8%, limiting the normative evaluation of deformation calculations for hybrid reinforced concrete beams considering bond slip. Finally, the influence of bond-slip parameters ( τm, sm and [Formula: see text]) and reinforcement configurations (equal stiffness reinforcement ratio, steel/BFRP reinforcement ratio, and post-yield stiffness ratio) on beam deformation and crack width was investigated. The results indicate that the peak bond strength is a key parameter affecting crack width and deformation of the beam. The exponential rise segment parameter α and the slip sm corresponding to peak bond strength mainly influence the load level corresponding to cracking.

Flexural performance and crack width prediction of steel-UHTCC composite bridge decks with wet joints

Composite bridge deck (CBD) structure has been widely used in recent decades, particularly in long-span bridges. The application of ultra-high toughness cementitious composite (UHTCC) in composite bridge deck (CBD) structures has garnered attention due to its exceptional resistance to tensile cracking and strain hardening. However, their widespread adoption necessitates a thorough understanding of crack resistance, especially in the presence of wet joints between cast regions. This study investigates the flexural performance and crack width prediction method of steel-UHTCC/concrete CBDs with wet joints using a combined experimental and theoretical approach. Six specimens with UHTCC wet joints and either UHTCC or concrete precast layers were designed and tested under hogging moment. The analysis focused on failure modes, load-deflection responses, and crack development while considering the wet joints. All specimens exhibited interfacial slip between the UHTCC/concrete layer and the steel beam. A novel theoretical model was developed to predict crack width in steel-UHTCC/concrete CBDs with wet joints. This model incorporates established crack theories for fiber-reinforced concrete while explicitly accounting for the strain-hardening behavior of UHTCC. Furthermore, this model provides a detailed bending analysis of steel-UHTCC CBDs considering the interface slip phenomenon, to derive various mechanical parameters for crack width prediction.

Prognosis of reflective pavement cracking development with Bayesian updating and surrogate models

ABSTRACT The main objective of this study is to establish an integrated prognostic method for predicting the development of thermal-induced reflective cracking in asphalt overlay on concrete pavement. The integrated prognosis process for crack growth is developed on the modified Paris’ law and includes three steps: (1) calculation of J-integral; (2) Bayesian updating of crack growth parameters and (3) prediction of remaining life. Finite element modelling (FEM) was conducted to calculate J-integrals at different crack depths and cold weather conditions. A surrogate model was built based on the original Kriging method and it shows high accuracy in predicting J-integrals from maximum air temperature, temperature drop and crack depth. The Bayesian updating process starts from the laboratory-measured distribution of fracture model parameters (A and n) in Paris’ Law and converges to the true values to match the measured crack depths at different loading cycles from field inspection. On the other hand, the consideration of material damage in asphalt overlay avoids over-estimation of remaining loading cycles for reflective cracking to reach the pavement surface. Further study is recommended to accurately assess in-situ pavement modulus and detect crack depth over concrete joints for implementation of the proposed prognostics method.

Numerical analysis of failure mechanics of concrete under true dynamic triaxial loading using a four-phase meso-model

In the present paper, the failure mechanics of concrete under true triaxial dynamic loading is investigated. A four-phase concrete meso-model is developed. The meso-model consists of aggregate, mortar, interfacial transition zone (ITZ) and macropores. A finite element (FE) model of a split Hopkinson pressure bar is also created to apply true triaxial dynamic loading. The development of cracks in concrete is presented for the uniaxial, biaxial and triaxial loading cases. The presence of local discontinuity is modelled, and its effect on the failure of concrete is extensively investigated and discussed. In the last, the effect of aggregate distribution is also analysed. It is found that the internal structure of concrete changes the stress distribution from true triaxial to compression or extension triaxial, which is the prime cause of internal cracking.

Study on the compressive strength and failure mechanism of fiber-reinforced polymer green filling materials

The utilization of industrial solid waste in the preparation of geopolymer filling materials offers benefits such as low carbon emissions and resource conservation showcasing broad application prospects. In this study, geopolymer filling materials are prepared using calcium carbide slag, slag, fly ash, and tailings, with the addition of 12 mm polypropylene fibers to enhance their strength and toughness. Conducting UCS experiments to investigate the effects of different calcium carbide slag content, fiber content, and water-solid ratio on the UCS of the materials; Utilizing SEM-EDS and XRD techniques to analyze the mechanisms of strength formation in filling materials and the mechanisms of fiber toughening and crack resistance at the micro level; Establishing a uniaxial compression test model using discrete element PFC 3D software and combining digital speckle technology to visually analyze the sample's failure process. The research results indicate that the stimulation of slag and fly ash by calcium carbide slag results in a large amount of C-(A)-S-H gel, effectively promoting the bond between aggregate and fiber, with the UCS of the samples gradually increasing with the addition of calcium carbide slag. With the increase in fiber content, the UCS of the samples shows a trend of first increasing and then decreasing, with the optimal fiber content being 6 ‰. The fibers exist in the matrix in the form of anchor rods and a three-dimensional network structure, playing a good reinforcing role and effectively inhibiting the expansion and development of cracks; The crack morphology of the samples in the PFC 3D numerical simulation process is close to the digital speckle failure morphology, and the axial load-displacement curve in the numerical simulation aligns well with the indoor test results. The research results can provide theoretical guidance for the preparation of fiber-reinforced green filling materials using all solid waste.

Interfacial interaction mechanism and theoretical bond strength model between UHPC-CA and steel bar

The bond property is the basis of the bear collectively load between the steel bar and Ultra-High Performance Concrete with Coarse Aggregate (UHPC-CA). In this paper, the theoretical calculation method of bond strength between UHPC-CA and high-strength steel bar is studied. The chemical adhesion strength, friction coefficient, and mechanical interlock process of the two were investigated respectively through the refined bond property tests. The failure model is established from the interlock failure characteristics, and the bond strength is obtained theoretically. Results show that the chemical adhesion strength and friction coefficient between UHPC-CA and steel bars are 0.07MPa and 0.5, respectively. The friction coefficient between UHPC-CA is 1.15. The interlock failure process of UHPC-CA and steel bars can be divided into three stages: uncracked stage, crack development stage, and split stage. The crack develops at an angle of 52° to the steel bar's axis and tends to stagnate at a height of 4.5 times the rib. A theoretical bond strength model is established and it is proved that the model is applicable not only to UHPC-CA but also to UHPC. This study can provide a theoretical basis for determining the anchorage length of steel bars in the design of UHPC-CA/UHPC structure, and can also provide a reference for the formulation of relevant standards.

Dynamic tensile behaviors and crack propagation in fiber-reinforced cementitious composites: Experimental investigation and Peridynamic simulation

Fiber-Reinforced Cementitious Composites (FRCC) have gained significant attention in engineering applications due to their superior mechanical properties and toughness, particularly under high strain rate conditions. This study performed dynamic tensile tests on FRCC at high strain rates (35-110 s⁻¹) using a Split Hopkinson Tensile Bar (SHTB) apparatus. Additionally, a novel Peridynamic (PD) model was developed for the SHTB and FRCC system, leveraging the advanced capabilities of the emerging PD theory. The study compared and analyzed dynamic tensile strength, ultimate tensile strain, strain rate effects, failure modes, and crack development in FRCC with different fiber ratios at various high strain rates, using both experimental data and PD simulations. The results show that the PD-SHTB-FRCC dynamic model developed in this study exhibits high consistency between numerical simulations and experimental findings, effectively capturing the processes of crack initiation, propagation, and complete failure in FRCC specimens. The dynamic tensile properties of FRCC improve significantly with increased strain rates, with polyethylene (PE) fibers providing superior reinforcement compared to steel fibers. Notably, the dynamic tensile strength, peak tensile stress, and ultimate tensile strain of FRCC increase significantly with rising strain rates, with specimens containing higher PE fiber content showing a more pronounced enhancement effect. For strain rates between 42.6 s⁻¹ and 76.1 s⁻¹, considering dynamic tensile strength, ultimate tensile strain, and peak tensile stress, the optimal combination for resisting dynamic tensile loads was 1.5% PE fibers and 0.5% steel fibers. At a strain rate of 99.8 s⁻¹, a 2% PE fiber ratio alone provided the best performance.

Experimental study on the Mode l fracture toughness of frozen silty clay incorporating Digital image correlation

To investigate the effects of initial moisture content and temperature on the Mode I fracture toughness (KIc) of frozen silty clay, a series of three-point bending tests were conducted. Rectangular specimens with prefabricated cracks were tested, and digital image correlation (DIC) technology was employed to analyze the microscopic characteristics at the crack tip. The results indicate that the Mode I fracture toughness of frozen silty clay increases with decreasing temperature and increasing initial moisture content. Temperature governs the failure mode, with plastic failure predominantly occurring at high temperatures and brittle failure at low temperatures. Based on the load–displacement curves and DIC recordings, the macroscopic fracture process of the specimens can be categorized into three stages: elastic deformation, formation of the failure surface, and specimen failure. Additionally, the crack propagation process can be further divided into three stages: initiation and development of microcracks, transition from microcracks to macroscopic cracks, and rapid development of macroscopic cracks. These findings provide critical insights for slope stability research in cold regions and offer new perspectives for engineering design and construction in similar environments.

Experimental investigation of seismic performance of precast concrete shear walls with overlapping U-bar loop connections

This paper discusses the seismic performance of five reduced-scale shear walls, including one cast-in-place (CIP) concrete shear wall, two precast concrete (PC) shear walls with overlapping U-bar loop connections, and two PC shear walls with modified form-overlapping U-bar loop connections combined with extruded sleeve connections. A quasi-static test was conducted to evaluate the reliability of the overlapping U-bar loop connections and the modified form by comparing the corresponding mechanical parameters of PC specimens with those of the CIP specimen. Moreover, the differences in seismic performance between the CIP specimen and PC specimens with different connection methods were also analyzed in terms of damage process, hysteretic loops and skeleton curves, load carrying capacity, ductility, equivalent stiffness, and energy dissipation. The experimental findings indicated that the mechanical performances of PC specimens with the modified connection form outperformed those of PC specimens with pure overlapping U-bar loop connections, closely resembling the properties of cast-in-place specimens; the failure mode of PC specimens was consistent with that of the CIP specimen; the generation, distribution and development of cracks in PC specimens were also similar to those in the CIP specimen. Furthermore, although the load-bearing capacity and peak displacement of PC specimens were lower than those of the CIP specimen due to the failure of the post-casted concrete strength to meet the requirements, the ductility, equivalent stiffness, and energy dissipation of PC specimens with the modified connection form closely matched that of the CIP specimen.

Seismic Performance of Precast Concrete Bridge Piers with Built-In Steel Tube Connection Key

Investigating the seismic behavior of precast concrete bridge piers is crucial in the design process due to the complex stress distribution in the connecting components. To demonstrate the seismic behavior of precast concrete bridge piers with hybrid joint connections, three bridge piers were designed with a scaling ratio of 1:8 and then tested under low cyclic loading conditions. The tests involved varying shapes of steel tube connection keys as parameters. This study involved examining failure modes and crack development, as well as analyzing the hysteretic performance, deformation capacity, energy dissipation, and stiffness degradation of the specimens. Furthermore, a finite element model was developed using ABAQUS, and the validity of the modeling approach suggested in this study was confirmed through tests. The results indicate that the precast piers exhibit reduced concrete damage at the joints. The enhanced strength of the joints is attributed to the incorporation of steel tube connection keys. The circular steel tube connection key integrated into the precast bridge pier offers a superior bearing capacity, energy dissipation, and stiffness degradation compared to the cross-shaped steel tube connection key. The presence of the built-in circular steel tube connection key in the precast bridge pier suggests that it complies with the seismic structural measures and is consistent with the design principle of “strong joint and weak member”.

A Fractal Study on Random Distribution of Recycled Concrete and Its Influence on Failure Characteristics

In order to quantitatively describe the influence of aggregate distribution on crack development and peak stress of recycled aggregate concrete, a multifractal spectrum theory was proposed to quantitatively characterize aggregate distribution in specimens. A mesomechanical model of reclaimed aggregate concrete mixed with natural aggregate and artificial aggregate was constructed. Numerical simulation tests were conducted on the uniaxial compression mechanical behavior of 25 groups of sample models with the same proportion and different aggregate distribution forms. Based on the box dimension theory, the multiple fractal spectrum method was used to quantitatively characterize the aggregate distribution form, and the key factors affecting cracks were explored based on the gray correlation degree. The research results show that the aggregate distribution in recycled aggregate concrete has multifractal characteristics. The multifractal spectrum was used to effectively characterize the aggregate distribution pattern, which can enlarge local details and provide new ideas for the quantitative analysis of the damage mode of recycled concrete. Secondly, by establishing a statistical model of the correlation between the multifractal spectrum width of the aggregate distribution pattern and the crack distribution box dimension, it was found that there was a positive correlation between the two, that is, the greater the multifractal spectrum width of the aggregate distribution pattern, the greater the crack box dimension, and the more complex the crack distribution. The complexity of aggregate distribution is closely related to the irregularity and complexity of mesoscopic failure crack propagation in recycled concrete specimens. In addition, gray correlation theory was applied to analyze the key factors affecting the formation of cracks in the specimens. The results showed that aggregate distribution had a first-order correlation with crack formation, and changes in aggregate distribution were an important factor affecting the performance of recycled concrete. Secondly, the poor mechanical properties of NAITZ led to obvious material damage, while NCA and MZ had a significant impact on the skeleton effect in the stress–strain process due to their large areas. This study deepens people’s understanding of the damage characteristics and cracking failure modes of recycled concrete. The study verifies the feasibility of the application of recycled aggregates and provides a valuable reference for engineering practice.

Study on the Mechanical Behavior of Top-Chord-Free Vierendeel-Truss Composite Slabs

A top-chord-free Vierendeel-truss composite slab (TVCS) comprises a concrete slab, several vertical webs, and a steel bottom chord. In this study, static tests and finite element analyses were conducted based on an actual project to investigate the deformation, crack characteristics, ultimate bearing capacity, and failure mode of the composite slab. The findings indicated that the loading process of this type of floor can be divided into elastic, elastoplastic, and failure stages. The section stress distribution in the elastic stage was further analyzed. The crack development pattern exhibited a fine density in the pure bending sections of the concrete slabs, while demonstrating good overall flexural bearing capacity and ductility for the composite slab. Experimental results were compared with the ANSYS finite element model simulation to validate the accuracy of the simulation. Parametric analysis was conducted to assess the impact of concrete strength, steel strength, vertical web width, and distance ratios on the mechanical characteristics of the composite slab. By introducing an adjustment coefficient for the vertical web distance ratio, a revised calculation formula for flexural bearing capacity was proposed, which aligned well with the finite element analysis.

Deformation mechanism and control technology of gob-side entry retaining with roadside backfilling: a numerical analysis and field investigation

The technology of gob-side entry retaining (GER) has the advantages in terms of higher resource recovery rate and lower drivage ratio. In this study, the GER implementation in N1217 panel in Ningtiaota Coal Mine, to verify the adaptability of the gob-side entry retaining with roadside backfilling, the FLAC3D numerical model was established, the stress evolution law and plastic zone distribution of the roadway surrounding rock were analyzed, the deformation characteristics of the roadway during the mining period were revealed, the roadway surrounding rock control technology was proposed, and the development of roof cracks was analyzed. The numerical results show that during the mining of the working face, the roadside backfill body and gangue are jointly loaded, the peak stress of the surrounding rock is transferred from the mining side to the solid coal side, the plastic zone of the roof and the solid coal side increases significantly, and the tensile and shear mixed failure occurs. Based on the evolution characteristics of the stress and plastic zone of the surrounding rock during the mining period of the working face, a collaborative control technology of the surrounding rock based on gangue retaining bracket + roadside backfill + bolt (cable) is proposed, and the borehole peep shows that the roadway is affected by roof fracture rotation and subsidence, which leads to the development of roadway overburden cracks and failures to the depth. The monitoring results indicate that the control measures are highly effective, with minimal roadway convergence observed and stable bolt (cable) supporting forces recorded. Additionally, hydraulic support resistance monitoring confirms that the roadway remains stable. It can ensure the safe mining of the working face of the Ningtiaota coal mine and other similar roadways.

Development of craquelure patterns in paintings on canvas

Canvas paintings are layered structures composed of canvas support sized with animal glue, a preparatory layer of the ground, and paint and varnish layers on the top. Preventing or limiting humidity-induced stresses in these structures requires an understanding of the relevant processes and risks. A three-dimensional model of a canvas painting was used to analyse stresses and crack development in the two-layer structure comprised of a glue-sized canvas on a wooden stretcher with a layer of stiff chalk-glue ground representing a pictorial layer in historic canvas paintings. The model was subjected to a large relative humidity fall which induced shrinkage of the glue-sized canvas. The modelling revealed that when a stretcher with flexible wooden bars is considered, high tensile stresses arise in the ground layer at the corners of the painting, and cracks are formed in these areas in the direction perpendicular to the painting’s diagonal. Ratios of critical distances between cracks to the ground layer thickness for which stresses in the midpoints between the cracks dropped to below the level inducing fracture in the material were estimated for various magnitudes of the relative humidity drop and thicknesses of the ground layer. Increasing ground layer thickness limits the hygric response of the sized canvas and makes the paintings less vulnerable to humidity variations. The ratio of stress along the diagonal calculated for painting with one crack to the solution without cracks was described by the double Lorentz function. A simple procedure of calculating stress variations along the diagonal—using the function—on a sequential addition of cracks was developed. Cracks in central parts of canvas painting were found to be induced by permanent cumulative drying shrinkage of the oil-based paints and grounds due to the evolution of the molecular composition of the oil binder. The outcome of the modelling indicated that the risk of cracking of the pictorial layers in canvas paintings due to drops in ambient relative humidity was small.

Study on seismic response of flexure-shear critical RC columns wrapped with TRC shells

Quasi-static tests were conducted on sixteen specimens to study the seismic response of flexure-shear columns wrapped with textile reinforced concrete (TRC) shells. Two RC square columns served as controls, while the remaining columns were wrapped with TRC shells. Three types of treatment methods were applied to TRC-wrapped columns herein to study the impact of different interfacial treatments on seismic behaviours. This study also analyzed the impacts of shear span ratios, axial load ratios, and number of textile layers on the seismic response of test columns. Results revealed that the TRC confinement layers could mitigate crack development, transforming RC columns' failure modes from flexure-shear to flexure. Due to greater confinement to the concrete core, TRC-wrapped columns exhibited enhanced performances compared to control columns, with peak loads, ductility, and cumulative energy dissipation increasing by up to 49.9%, 195.3%, and 5.7 times, respectively. TRC confinement layers could mitigate the shear effects in column specimens. TRC wrapping could improve the shear capacities of flexure-shear columns, with growth rates ranging from 25.2% to 60.4%. Eventually, an equivalent viscous damping model was proposed to assess the energy dissipation capacity of flexure-shear columns wrapped with TRC shells.

The effect of external force on the crack propagation of aluminum nanoplate using molecular dynamics approach: Insights into the fracture mechanisms of metallic nanomaterials under external loading condition

It is crucial to comprehend how external forces (EFs) affect crack propagation (CP) in aluminum (Al) nanoplates to develop and create nanomaterials with enhanced mechanical characteristics. The creation of novel materials for a variety of uses, such as the aerospace, electronics, and energy sectors, may benefit from this expertise. Additionally, insights into the fracture mechanisms of nanomaterials can aid in designing more reliable and durable structures at the nanoscale. This study utilized computer models to investigate the effect of EFs on fractures in Al nanoplates. The results suggest that an EF can significantly alter CP within nanoplates. The findings provide insights into the fracture mechanisms of metallic nanomaterials under external loading conditions. Simulation results in current research showed the physical stability of modeled Al nanoplates at T=300 K as the initial temperature. Numerically, the total energy (TE) of pristine nanoplate converged to −34762.953 eV after thermodynamic equilibrium detection inside the computational box. Furthermore, the simulation results show that EF caused the crack growth procedure intensity to increase. In the present study, the crack length value increased to 33.902 Å between our modeled samples. This result led to the conclusion that in real-world applications, it is important to consider the effect of EFs on the development of cracks within Al nanoplates.