Acoustic Emission Properties Research Articles

Statistical analysis of thermally induced pre-existing microcracks and their influence on fracture behaviours of granite rock

Rocks containing varying degrees of microcracks have a significant influence on their mechanical behavior. Understanding the effect of pre-existing microcracks (PEMs) on rock fracture mechanisms has scientific and practical value in areas such as geothermal energy, nuclear waste disposal and deep mining. We employed a thermally induced approach to create PEMs in granite rock, and quantified characteristic parameters of PEMs by visualization methods, focusing on the quantitative relationships between the PEMs and the mechanical strength and acoustic emission (AE) properties of the rock. We find that the distribution characteristics of thermally induced PEMs obey a lognormal distribution, and the length of individual thermally induced PEMs is almost independent of temperature. The density and orientation of PEMs together determine the variation of the longitudinal wave velocity and rock strength, with the effect of microcrack density dominating. The AE signal suggests that PEMs can affect the fracture behavior and fracture mechanism, depending on the relative dominance of pre-existing and stress-induced microcracks. The AF-RA values show that PEMs lead to an important shift in the fracture mechanism of the rock. When the microcrack density is low, tensile mode dominates the rock failure. Conversely, the shear mechanism dominates the rock fracture.

Effect of heat treatment on the shear fracture and acoustic emission properties of granite with thermal storage potential: A laboratory-scale test

The exploitation of geothermal resources enhances the energy structure but poses challenges related to thermal–mechanical issues. This study utilizes short core in compression (SCC) specimens of granite to investigate thermo-mechanical properties. We examined the effects of heat treatment temperature on physical properties, shear fracture toughness, as well as acoustic emission (AE) characteristics. Fracture surface morphology and microstructure of the heat-treated SCC specimens were also analyzed using 3D laser scanning and scanning electron microscopy. Results indicate that both mass loss and P-wave velocity decrease with increasing heating-treated temperature, and similar trends are observed in mechanical properties. Specifically, fracture energy and shear fracture toughness decline by 51.48 % and 61.27 %, respectively, as temperature rises from 25 °C to 750 °C. The b-value and proportion of shear cracks initially increase before falling, with an inflection point at 300 °C, linked to thermal-induced microstructural deterioration. Fractal dimension (D) and joint roughness coefficient (JRC) show significant increases with higher heat treatment temperatures. Microstructural degradation, including dehydration and thermal-induced microcracking, drives the reduction in shear properties of heat-treated granites. Overall, our findings offer valuable insights into determining various methods of heat storage reconstruction with great application potential.

Experimental Study on the Shear Failure Properties and Damage Constitutive Model of Rocks.

In the construction of underground geological engineering, a variety of rocks were often encountered, and the engineering surrounding rocks was prone to shear fracturing. Shear mechanics tests were conducted on a variety of rocks under various joint angles. By studying the shear mechanical characteristics, acoustic emission behavior, and damage degree of the different rock types, we can obtain an insight into their bearing capacity and fracture mechanisms. An obvious inflection point from the elastic to plastic behavior can be observed for the specimens during the process of shear mechanics tests, and the shear behavior was divided into three phases. The acoustic emission signals significantly increased for coal during the second phase, while those of sandstone and shale start to increase during the third phase, which is from the peak point to fracture. The analyses of the shear failure and acoustic emission properties showed that the crack propagation angle increases as the normal stress of rock increases. It was proved that the joint angles and normal stresses of rock could effectively hinder the development of vertical fractures. Based on the shear failure and acoustic emission properties, a constitutive model capable of describing the shear behavior of different types of rocks was developed. This constitutive model can accurately describe the shear fracture properties of the various rocks. The shear failure properties and damage constitutive model of rocks in this study can be used to reduce engineering surrounding rock instability caused by shear.

Experimental Study on Acoustic Emission Properties and Damage Characteristics of Basalt Exposed to High Temperature Treatment

Experimental Study on Acoustic Emission Properties and Damage Characteristics of Basalt Exposed to High Temperature Treatment

Acoustic emission based experimental study on mechanical properties and damage analysis of carbon nanotube reinforced fiber shotcrete

Fiber shotcrete support is an important method for initial support in tunneling, slope, and foundation pit projects. However, the strength of fiber shotcrete is affected by the substantial number of irregularly dispersed pores and microcracks due to the constraints of the spraying process, surrounding rock conditions, and construction environment. Therefore, to improve the mechanical properties of fiber shotcrete, this paper proposes the addition of carbon nanotubes (CNTs) to mixed alkali-resistant glass fiber-reinforced shotcrete (AR-GFRS). Mechanical experiments were used to examine the impact of CNT admixture and curing time on the strength of AR-GFRS. The acoustic emission (AE) properties and damage patterns of CNT glass fiber shotcrete (CNGC) specimens were examined using the AE monitoring technique. Scanning electron microscopy, or SEM, was used to analyze the specimens' microscopic characteristics. Research shows: (1) At 0.2 wt% CNT doping, the compressive strength and the split tensile strength of CNGC specimens were enhanced to peak values. (2) An increment in the ratio of CNT to the overall mass led to an increase and then a decrease in the values of the CNGC intensity and AE characterization parameters. (3) Combined with the RA-AF analysis, CNGC specimens showed more than 80 % of shear damage, so CNGC damage mode was more stable shear damage. (4) It was found by SEM that the incorporation of CNT promoted the production of hydration products and enhanced the homogeneity of the specimens. The results of this study add innovative ideas and references for the use of CNT-reinforced fiber shotcrete.

Mechanical properties and damage characteristics analysis on recycled aggregate concrete with glazed hollow beads after high temperatures by acoustic emission method

This research investigates the effect of high temperature on the mechanical and acoustic emission properties of recycled aggregate concrete with glazed hollow beads (GHB-RAC). Uniaxial compression tests were conducted on GHB-RAC at varying recycled coarse aggregate (RCA) substitution rates and glazed hollow beads (GHB) contents, and acoustic emission (AE) technology was used to monitor the compression-induced damage throughout the testing process. This study delves into the mechanical properties and damage characteristics of GHB-RAC when exposed to fire. The findings reveal that AE characteristic coefficients aptly delineate the three-stage nature of axial compression damage in concrete at temperatures up to 400 °C. However, these stage-specific traits vanish at temperatures exceeding 400 °C. Additionally, through the analysis of AE signals at different temperatures, the compression damage process is elucidated based on the b-value method. The RA-AF analysis indicates that the number of shear cracks exhibits an increasing trend with increasing temperature, and an increment in GHB dosage positively influences the percentage of tensile cracking during loading, with the influence being more significant at 70 % GHB content. The acoustic emission sensing can accurately detect and localise damage. With the increase in temperature, the distribution of AE signals depicting concrete damage is more dispersed and the number of AE signals is more larger. Notably, the incidence of localized damage points diminishes with a higher GHB ratio, indicating the efficacy of GHBs in mitigating thermal damage to the concrete. Furthermore, a damage constitutive model incorporating variables such as temperature, GHB dosage, and recycled coarse aggregate replacement rate was proposed. The model employed AE energy count parameters as the damage indicator. The good fitting results suggest that the mechanics behavior of GHB-RAC under uniaxial compression can be well described by the model. Consequently, the study offers invaluable insights into the damage evolution of post-fire recycled aggregate concrete with GHB admixtures.

Investigation of the impact of heating and liquid nitrogen (LN2) cooling on the mechanical and acoustic emission (AE) properties of coal

Liquid nitrogen has emerged as a promising fracturing medium for unconventional natural gas extraction, particularly in the context of coalbed methane extraction, generating significant interest in recent times. In this paper, we analyze the acoustic emission (AE) characteristics of coal samples treated with liquid nitrogen under three-point bending load conditions using indoor experiments and field investigations. We investigate the impact of liquid nitrogen on coal samples by analyzing AE data. The mechanical properties of coal samples with varying initial temperatures were tested under three-point bending load conditions after treatment with liquid nitrogen. The load-displacement curve was analyzed to study the mechanical properties of the coal samples after treatment with liquid nitrogen. Through indoor three-point bending experiments, data analysis, and knowledge of mechanics, we systematically investigated the changes in mechanical properties caused by liquid nitrogen treatment under different conditions. The results demonstrate that the application of liquid nitrogen has significant impacts on the mechanical and AE characteristics of coal samples. The load-displacement curve indicated that the mechanical properties of the coal samples changed after treatment with liquid nitrogen. The AE experiment revealed regular changes in vibration and energy parameters of coal samples after liquid nitrogen treatment under different conditions. We further investigated the changes in mechanical properties and deformation characteristics of coal samples after undergoing liquid nitrogen freezing and thawing in differing environments. Graphs such as load-displacement curves, load-time curves, cumulative vibration count-energy count graphs, and RA-AF density distribution diagrams visually demonstrated the changes in mechanical properties and deformation characteristics. Through an integrated approach of indoor experiments, data analysis, and knowledge of mechanics, our study provides a better understanding of the behavior of coal samples under different conditions. This understanding can contribute to the development of safer and more efficient methods for extracting coalbed methane.

Effects of Temperature and Liquid Nitrogen (LN2) on Coal’s Mechanical and Acoustic Emission (AE) Properties

Effects of Temperature and Liquid Nitrogen (LN2) on Coal’s Mechanical and Acoustic Emission (AE) Properties

Theoretical study on resonance frequencies of vibration modes of Janus-Helmholtz transducer

Janus-Helmholtz transducer has the characteristics of high-power and broadband transmission due to the coupling between the longitudinal resonance of the driver and the liquid cavity resonance of Helmholtz resonator. Traditional view holds that the low frequency resonance peak in the transmitting voltage response curve in water is fluid cavity mode of Helmholtz resonator while the high frequency resonance is the longitudinal mode of Janus transducer. However, in the past few decades, a large number of experimental studies have found that this conclusion is questionable. This work is to distinguish the two resonances in the response curve and the two vibration modes of Janus-Helmholtz transducer. Based on the Janus-Helmholtz transducer prototype reported in the literature, the resonance frequencies of the vibration modes of Janus-Helmholtz transducer are studied theoretically. The structure dimensions and material parameters of the prototype are listed in detail. The test results and simulation results of conductivity are also presented. The longitudinal resonance of the driver is determined by using the equivalent circuit method and finite element analysis. Radiation masses of both Janus transducer and typical longitudinal vibration transducer are also calculated to analyze the phenomenon of the sharp decrease of longitudinal resonance frequency in water. Acoustic modal analysis by using ANSYS software is performed to investigate the resonance frequency of complex Helmholtz resonator in Janus-Helmholtz transducer. Correction length on the vent introduced by external fluid sound radiation is used to obtain the accurate Helmholtz resonance frequency. The sound pressure distribution of Helmholtz resonator obtained through finite element method is investigated, and the correct equivalent formula for solving the Helmholtz resonance frequency is obtained. The results reveal that the first resonance in the response curve is driver resonance while the second one is Helmholtz resonance, which is contrary to the traditional view. The considerable reduction of driver resonance frequency in water is mainly due to the large radiation mass on the four large radiation surfaces of the Janus transducer, which also causes the sharp response of driver resonance. In Janus-Helmholtz transducer, there are two Helmholtz resonators with the same size, instead of only one resonator in the traditional view. The two resonance frequencies solved by the method proposed in this work are in good agreement with the test and simulation results. These conclusions play an important role in correctly understanding the structure and characteristics of Janus-Helmholtz transducer at source, as well as provide technical support for structural optimization and innovation, thus improving the acoustic emission properties of the transducer.

Experimental study on fracture and acoustic emission properties of internally cured concrete with super absorbent polymer subjected to high temperature

The three-point bending experiment was conducted on notched beams containing five different SAP contents to investigate the influence of high temperature on the fracture performance of Superabsorbent Polymer (SAP) concrete. Acoustic Emission (AE) technology was employed to monitor real-time crack propagation, and scanning electron microscopy (SEM) was utilized to analyze the micro-pore structure. The experimental results reveal the following findings. After exposure to high temperatures, the peak strength of SAP concrete continuously decreases. Compared to specimens at 20 °C, the strength loss after exposure to temperatures of 200 °C, 400 °C, and 600 °C is approximately 11%, 55%, and 87%, respectively. However, the introduction of SAP can reduce the proportion of strength loss in the concrete. Additionally, SAP improves the toughness of the concrete, with an increase in ductility coefficient ranging from 4.0 to 6.8 times as the loading temperature increases. Similar to the strength variation pattern, the initial fracture toughness of SAP concrete exhibits a significant decrease with increasing heating temperature. The loss in initiation toughness after exposure to temperatures of 200 °C, 400 °C, and 600 °C is approximately 11%, 42%, and 85%, respectively, while the loss in unstable fracture toughness is 11%, 46%, and 74%. Based on the experimental results, this study proposes two temperature-dependent fitting models for the peak strength and fracture toughness of SAP concrete, which are compared and validated with the experimental results. SEM analysis reveals a loose and porous internal structure in SAP concrete. Through the analysis of AE signals at different temperatures, the fracture process is elucidated based on the b-value method. Moreover, RA-AF analysis indicates that an increase in temperature reduces the proportion of tensile-type cracks in specimens with the same SAP content. From the temperature loaded results spanning 20 °C–600 °C, the proportion of tensile cracks decreases from 80% to 50%, indicating a transition in the failure mode from tension to shear. However, this trend is not significantly affected by the temperature increase, suggesting that the failure mode of the specimens is primarily determined by the internal pore structure of the concrete rather than the temperature load. The research findings provide experimental evidence for the application of SAP concrete in engineering projects.

Precursors of Cyclic Loading and Unloading Sandstone Failure Based on “Acoustic-Thermal” Loading–Unloading Response Ratio

Coal mining often causes periodic disruption in the rock mass around the stope. The study of the deformation and failure characteristics of cyclic loading and unloading sandstone is very critical for gaining a thorough understanding of the mechanisms of rock damage, degradation, and failure. This kind of investigation is very helpful in determining the precursors of rock failure and the instability of engineering structures. In this research study, the properties of acoustic emission and infrared radiation of cyclic loading and unloading sandstone are explored using a cyclic loading and unloading sandstone experiment. Based on acoustic emission and infrared radiation, the loading–unloading response ratio of rock is established. It is found that the response variables of sandstone during the loading stage based on acoustic emission (AE) counts and the loading–unloading response ratio based on average infrared radiation temperature (AIRT) both rise suddenly in the last cycle, which may be a precursor of “acoustic-thermal” approaching rock failure. On this basis, the quantitative analysis index of infrared radiation of differential infrared energy change rate (DIECR) is proposed, that is, the change of square of ΔAIRT in unit time, and based on AE counts and DIECR, the loading–unloading response ratio of “acoustic-thermal” is defined. It is found that the “acoustic-thermal” loading–unloading response ratio suddenly increases during the penultimate cycle of loading and unloading. This feature can be taken as the initial precursor of rock failure. Together with the “acoustic-thermal” imminent failure precursor of rock, it constitutes the “initial precursor-imminent failure precursor” combined with the internal fracture and surface infrared radiation temperature field during the cyclic loading and unloading process of rock, realizing the hierarchical monitoring and early warning of cyclic loading and unloading rock failure. The research results lay a theoretical and practical foundation for using infrared radiation to monitor engineering disasters caused by rock fracture and failure in mining engineering.

Influence of arch shaped notch angle, length and opening on the failure mechanism of rock like material and acoustic emission properties: Experimental test and numerical simulation

The uniaxial compressive failure mechanism of rock like specimens with arched shaped notches was studied experimentally and numerically considering the effects of cracks’ properties on the mechanical behavior of the rocks. The rock like material specimens were provided in laboratory in form of cubes with dimensions of 150 mm × 150 mm × 50 mm containing one arch shaped notch at the center of the specimen where, the notch diameter was changed as 20 mm, 40 mm, and 60 mm. the notch apperture was also varied as 2 mm. 4 mm and 6 mm. The axisymetric axis of the arched notch made angles changed from 0° to 90° by increasing the 15°. In this research 63 different models of the compression tests were made by the two-dimensional particle flow code (PFC2D). The experimental tests and their numerical simulations performed simultaneously to compare them for the arch shaped notch tests under compression. The results of these analyses revealed that the geometric characteristics of the arch shape notch such as the notch diameter, angle and its opening (aperture) governe the failure process of the models and tests under compressive loading conditions. It is also shown that the failure mechanisms of the arch shaped notches and their fracture modes are associated with the compressive strengths of the testing samples. The changes in notch diameter, notch angle and notch opening may make some significant changes in AE hits during the failure process of the specimens. The AE hits grow rapidly after the loading process and before the peak load. Any stress drop may be detected by changes in AE hits during the test. It is concluded that the fracture pattern and failure of the experimental tests and their corresponding numerical simulations are similar to one another which verify the validity and accuracy of the proposed approaches in this research.

Study on acoustic emission properties and crack growth rate identification of rail steels under different fatigue loading conditions

The acoustic emission (AE) technique is a non-destructive real-time dynamic monitoring technique for structural health. Nonetheless, there has been a lack of research on the initiation and propagation mechanisms of fatigue cracks in rails. In this paper, the AE signal properties of fatigue crack initiation and growth are studied in three types of rail materials under different fatigue loading conditions, and a method is proposed to identify the fatigue crack growth rate. The results show that this method has good applicability for different rail materials, and the crack growth rate can be quantitatively identified based on the AE energy growth rate.

Синхронизация мультифрактальных свойств непрерывной акустической эмиссии при подготовке и реализации подвижки по модельному разлому

According to the stick-slip model, the relative movement of the fault planes is an act of unstable sliding, where movement begins when the stresses tangential to the fault plane reach a certain limit. The physical mechanism of dynamic slip along a fault consists of the sequential formation of conglomerates of loaded particles (force chains) in the contact zone and their subsequent destruction. These chains together form a force skeleton characterized by a specific spatial structure and strength properties. An increase in shear stress on the fault banks leads to local destruction of the strength skeleton; further evolution of the system brings destruction processes to higher spatial levels, ultimately leading to a shift in the fault banks. Since the evolution of the process of destruction of force chains in the contact zone of a fault along the hierarchy of scales from bottom to top is similar to the evolution of crack formation in a loaded medium from microscale to macroscale (specimen scale), the authors hypothesized the coherent behavior of acoustic noise accompanying the preparation of dynamic slip and recorded in different areas of fault zones. This work is devoted to testing this hypothesis on a laboratory scale, using an installation that simulates movement along a fault. As a result of the analysis, the hypothesis about the synchronization of the statistical properties of the acoustic emission during the preparation and implementation of the dynamic movement was confirmed. It is shown that the observation (detection) of the effect of the synchronization of the statistical properties of acoustic emission depends both on the set of parameters for which the spectral coherence measure is calculated and on the location of the recording of the initial data.

EFFECT OF SYNCHRONIZATION OF CONTINUOUS ACOUSTIC EMISSION STATISTICAL PROPERTIES DURING STRUCTURALLY HETEROGENEOUS MATERIALS DEFORMATION

In this paper, a correlation analysis of the statistical properties of continuous acoustic emission recorded in various parts of marble and glass fiber laminate samples during their quasi-static deformation is carried out. The spectral measure of coherence, which is a generalization of the square modulus of the coherence spectrum to the case of multidimensional series, is chosen as a correlation measure. The measure of coherence was estimated for the width of the multifractal spectrum and the spectrum carrier realizing its maximum, calculated in a sliding time window for acoustic emission signals. It is shown that the preparation of a macrofracture site is accompanied by synchronization of the statistical properties of acoustic emission in the selected frequency intervals. Based on the analysis of changes in the frequency-averaged measure of coherence for both types of materials, four characteristic stages are distinguished, the boundaries of which are individual for each of the materials. The onset of the fourth stage, which is characterized by a monotonic increase in the average measure of the coherence of the statistical properties of the AE, can be chosen as a possible criterion for the transition of the material to the limiting state.

Strain rate effects on characteristic stresses and acoustic emission properties of granite under quasi-static compression

In order to further investigate the strain rate effects on characteristic stresses and acoustic emission parameters of rock under quasi-static compression, uniaxial compressive tests were conducted on cylindrical specimens measuring 50 mm in diameter and 100 mm in height using a rock material testing machine and a multi-channel acoustic emission monitoring system at strain rates ranging from 10–6 s−1 to 10–2 s−1. The stress-strain curves of rock samples, characteristic stresses, energy data, and temporal and spatial distribution of acoustic emission signals were obtained and analyzed. The experimental results certified a linearly positive correlation between characteristic stresses and the logarithm of strain rates, despite the fact that the linear correlation varies for different characteristic stresses, whereas the ratios of characteristic stresses essentially do not change with increasing strain rates. The input energy and elastic strain energy at the damage point, UCS point and failure stress point exhibit a linearly positive correlation with the logarithm of strain rates when the strain rate exceeds 10–5 s−1. Meanwhile, the characteristics of energy conversion between input energy and elastic strain energy or the dissipated energy at different characteristic stresses points were explored. Based on this, the energy conversion process of rock under quasi-static compression can be divided into three stages: energy accumulation, energy dissipation, and energy release, respectively. Besides, it is noted that the total number of the located AE events decreases as strain rates increase when the strain rate exceeds 10–5 s−1, and the majority of located AE events occur during the crack closure stage and unstable crack growth stage. Finally, based on the perspective of energy conversion and the structural properties of multi-scale defects in rock, the mechanism of the increase of characteristic stresses with the increase of strain rates was proposed: that is, when rock is subjected to quasi-static compression, the higher strain rates can activate the small-scale defects, which necessitates more input energy from the external load via continuous work and causes an increase in the associated characteristic stresses.

Study on Acoustic Emission and Damage Mechanical Properties of Freeze-Thaw Sandstone under Uniaxial Compression

The damage strength of freeze-thaw rock provides an important reference for stability evaluations used during rock engineering in cold regions. In this paper, real-time acoustic emission tests of saturated sandstone are performed after various freeze-thaw cycles to study the uniaxial compressive strength and deformation characteristics of the resulting materials. The macro-meso damage evolution law of loaded sandstone is studied under the action of freeze-thaw cycles. The results show the following: (1) The saturated water absorption of sandstone increases, the peak strength and elastic modulus loss rates of sandstone increase linearly, and the frost resistance of the rock decreases with the number of freeze-thaw cycles. The sandstone failure mode gradually shifts from splitting failure to complex splitting shear failure of the failure surface. (2) If fewer than 10 freeze-thaw cycles are applied, the ring count signals at the compaction stage and after the peak strength is reached are extremely weak under a uniaxial compression load. With additional freeze-thaw cycles, damage inside the rock accumulates gradually, and the ring count signal appears during the rock compaction stage, fluctuates up and down, and continues until the peak strength is reached. When the compressive strength reaches its peak, the ring count intensity signal increases suddenly, and the frequency is high. After the strength reaches its peak, the acoustic emission signal shows that the rock sample still has some residual strength. As the number of freeze-thaw cycles increases, the cumulative ring count of sandstone gradually changes from the jumping stage to gradual growth. The acoustic emission characteristic parameters and ring count reflect damage to and expansion of freeze-thaw sandstone. (3) The cumulative extent of rock damage reaches the threshold value under loading and increases linearly until the rock is destroyed. When more freeze-thaw cycles are used, the time required for the rock to reach this threshold value is shorter, and the time required for sandstone damage is reduced gradually. These results provide a reference for the study of freeze-thaw damage and rock stability in cold regions.

Experimental Study on Fracture and Acoustic Emission Properties of Internally Cured Concrete with Super Absorbent Polymer Under Different Loading Rates

Experimental Study on Fracture and Acoustic Emission Properties of Internally Cured Concrete with Super Absorbent Polymer Under Different Loading Rates

Experimental research on the mechanical and acoustic emission properties of layered sandstone during tensile failure

Bedding planes exert great influences on the mechanical properties of layered rocks. To investigate influences of properties of bedding planes on the strength, failure mode, and acoustic emission (AE) characteristics of rocks, three-point bending tests were carried out on layered sandstone containing bedding planes of different dip angles. Results show that the failure strength of the layered sandstone shows a first large decrease and then slight increase trend with the rise of the dip angle θ of bedding planes under both conventional loading and multi-block cyclic loading. According to failure characteristics of the rock, the failure can be divided into three modes: matrix failure, mixed failure, and failure of bedding planes. In addition, the damage characteristics reflected by the AE count and AE energy, RA-AF distribution characteristics, and AE source locations show consistency in the same failure mode. Influenced by the multi-block cyclic loading, the failure strength, peak deformation, damage ratio reflected by the AE count and AE count at failure, and the number of shear cracks reflected by the RA-AF distribution of rocks with bedding planes of the same dip angle all increase to different extents. Moreover, the majority of residual deformation and damage in the loading process occurs in the initial period of cyclic loading and unloading in each block. The research result represents a useful complement to the mechanics theory of layered rocks and is of important significance for ensuring the safety of rock engineering.

The influence of sintering temperature on the mechanical evolution of Al2TiO5 flexible ceramics based on the acoustic emission

To explore the influence of sintering temperature on mechanical properties of Al2TiO5 (AT) flexible ceramics, the XRD/Raman, SEM and acoustic emission (AE) technology were used to estimate the phase composition, microstructure evolution and damage behaviors of AT ceramics, respectively. Results show that the diffraction peaks of AT increase before rising sintering temperature from 1300 °C to 1500 °C and then start to decrease at 1600 °C due to the decomposition of AT grains. In specimens with sintering temperature of 1300 °C and 1400 °C, intergranular fractures are more likely to occur, which controls the origination of AE events in the whole stage. And the fracture of big bodies composed by large number of fine AT grains is the main source of AE events with high energy level at initial stage. In addition, Thanks to the more transgranular fracture in specimens with sintering temperature of 1500 °C and 1600 °C, the number of AE events in these two specimens are more than that of specimens with sintering temperature of 1300 °C and 1400 °C.