Decrease In Maximum Stress Research Articles

Damage investigation of hybrid flax-glass/epoxy composites subjected to impact fatigue under water ageing

The aim of this study is to investigate the fatigue behaviour of hybrid flax-glass/epoxy composites under repeated impact loading subsequent to water ageing. Different plates of these composite materials were fabricated using the vacuum infusion technique. Five stacking sequences were considered: [F8], [G/F3]S, [G2/F2]S, [G3/F]S, and [G8], where F and G stand for flax/epoxy and glass/epoxy plies, respectively. Water ageing was conducted by immersing the composite specimens in tap water at room temperature for various durations, and until saturation was reached. Fatigue impact tests were carried out using three impact energies: 3, 4, and 5 J. An advanced high-resolution camera was used to monitor the evolution of damage mechanisms occurring on the non-impacted surfaces, while a laser thermometer was considered to track the temperature variations within each composite specimen. The obtained results show that flax-glass hybridization reduces the mass of absorbed water in flax/epoxy composite by up to 70%. Furthermore, there is a more pronounced decrease in longitudinal modulus and maximum stress in aged composites, with reductions of up to 70% compared to unaged ones. Additionally, visible damage occurs even at low energy levels, manifesting from the initial impacts in both aged and unaged composite laminates. Moreover, a correlation between the number of impacts to failure and the cumulative energy is revealed. Ultimately, water aging reduces the strength of the studied composite laminates and their resistance to impact fatigue. Furthermore, the hybrid laminates with high proportion of flax layers are particularly susceptible to water ageing effects.

Orthogonal cutting of 3D printed multi-material workpiece: numerical investigation of machining forces, stress, and temperature distribution

AbstractWith the development of 3D metal printers for rapid prototyping and industrial component production, heightened attention was directed towards post-processing operations for achieving precise surface quality and geometrical tolerances for these components. This paper investigated the orthogonal cutting of multi-material 3D printed workpieces using a coated cutting tool through finite element simulation. The workpieces featured different horizontal and vertical arrangements of layers composed of aluminum 7075-T6 alloy (Al), stainless steel 316 low alloy (SS), and Ti6Al4V alloy (Ti). The study explored the impacts of multi-material composition, coating thickness, and the rake angle of the cutting tool on machining forces, stress distribution, temperature distribution, and chip formation geometry. The results revealed a bimodal chip morphology in the machining process of horizontally arranged SS layers combined with other alloys. The SS layer resulted in a relatively uniform chip formation, while layers with two other materials exhibited a serrated chip formation. In contrast, a discontinuous chip formed when combining Al and Ti materials, as well as in the horizontally arranged layers made of Al, SS, and Ti alloys. The cutting force increased by 2.26 times when cutting workpieces with the horizontal arrangement of SS and Al layers compared to those with a single Al material. For the horizontal and vertical arrangement of layers made of Al and SS, von Mises stress values over the edge of the coated cutting tool significantly increased where the tool contacted the SS layer. Additionally, the horizontal arrangement of layers made of Al and SS materials caused the coated cutting tool to exhibit an extensive temperature distribution, with the maximum recorded temperature reaching 1448 °K. Increasing coating thickness led to a decrease in maximum principal stress at the surface of the tool and a rise in temperature at the cutting edge of the insert.

Progressive failure analysis of laminar composites under compression using smeared crack-band damage model and full layerwise theory

This paper presents an original finite element (FE) model that integrates the smeared crack band (SCB) approach and full layerwise plate theory (FLWT). The model enhances the computational efficiency of progressive failure analysis (PFA) of laminar composites in compression, by utilizing the layerwise approach which reduces a 3D model to a 2D one. The model distributes damage throughout the FE domain, with fracture mechanisms represented by material stiffness degradation controlled by damage variables (based on equivalent strains specifically defined for each failure mode). Mesh dependency issues are addressed by scaling fracture energy using a characteristic element length, and failure initiation and modes are determined using the 3D Hashin failure criterion.Accurately describing lamina response in fiber direction under compression requires linear-brittle softening with a stress plateau. The study showed that a model considering 30 % of residual stress accurately predicts maximum stress regardless of mesh refinement, demonstrating results’ minor dependence from the selected element size.The model accuracy has been confirmed by comparing the obtained results against experimental and benchmark data from the literature. The size effect study demonstrated a decrease in maximum stress of the open-hole laminates in compression with increasing specimen in-plane size. This trend is consistent with experimental and reference numerical observations, confirming the model accuracy and applicability even for relatively coarse meshes. Therefore, computational efficiency is improved, with preserved accuracy of conventional solid finite element models.

Investigation of speed and temperature effects in mechanical nano-patterning of GaAs via molecular dynamics simulation

Speed and temperature are two key parameters governing GaAs mechanical nano-patterning process. For the first time, this study evaluates the effects of pressing speed and nanoimprinting temperature on the deformation behavior and mechanical properties of GaAs in the mechanical nano-patterning process. Simulation results reveal that high pressing speed and high nanoimprinting temperature facilitate the nano-pattern formation on GaAs. For the pressing speed effect, the maximum force, residual stress, and cubic diamond atomic friction decrease with the elevated pressing speed, while the surface pile-up is minimally influenced by the pressing speed during the nanoimprinting process. Moreover, the morphological accuracy of the nano-patterns is enhanced with increasing pressing speed. For the temperature effect, simulation results reveal that amorphization and plastic activity exhibit a positive correlation with increasing nanoimprinting temperature, whereas the maximum force and residual stress demonstrate a roughly inverse relationship with nanoimprinting temperature. Additionally, the elevated temperature also exerts a substantial influence on the dislocation density, morphological accuracy, and surface pile-up. This study contributes to a comprehensive understanding of the effects of these two key factors on the mechanical properties and deformation behavior of GaAs in mechanical nano-patterning.

Analysis of the mechanical response of solid rocket engine propellant under acceleration shock

The increased-range solid rocket engine of new ammunition often needs to withstand extremely high acceleration overload, leading to damage to the propellant’s structural integrity. To address this issue, this paper constructs a nonlinear viscoelastic constitutive model for the CMDB propellant by using low- and high-strain rate mechanical property tests. Combined with the secondary development of explicit dynamics and numerical simulation technology, the mechanical response of a certain type of solid rocket propellant under different acceleration impacts is analyzed. The results show that under acceleration impact loads, the propellant will compress, rebound, and recover over time, continuously cycling. Its axial displacement, maximum equivalent stress, and maximum equivalent strain exhibit irregular sinusoidal wave-like periodic cycles. Looking at the time when the peaks appear, the time when the maximum equivalent stress appears always lags behind the time when the maximum axial displacement peak appears. Due to the viscous effect of the viscoelastic material of the propellant, the time when the equivalent strain peak appears will lag behind the equivalent stress. Because of the material’s damping effect, both the peak values of the maximum equivalent stress and equivalent strain decrease over time. Under continuous high acceleration impact loads, this viscous damping phenomenon continuously diminishes, and the peak value of the propellant’s axial displacement gradually increases.

Study on Dynamic Response and Vibration Reduction Characteristics of Rubber Concrete Tunnel Lining

In this paper, the dynamic response characteristics of rubber concrete tunnel lining are studied when the cross clearance of intersecting tunnel is 3 m, 6 m, 9 m and 12 m respectively, the results show that the vertical displacement, vertical acceleration and maximum principal stress of the measuring point increase gradually as the train moves closer to the measuring point, and decrease to zero after reaching the final value, moreover, the vertical displacement, vertical acceleration and maximum principal stress of the vaults of the two tunnels are the largest, and with the increase of the cross-section net distance, the vertical displacement, vertical acceleration and maximum principal stress of the monitoring points at the vault of section a decrease gradually. Taking the A-d test points as an example, the vertical displacement of the corresponding test points of the rubber concrete lining decreases by 0.0125 mm, 0.0074 mm, 0.0054 mm, 0.0040 mm respectively compared with that of the normal concrete lining when the cross clear distances are 3m, 6m, 9m and 12m, the vertical acceleration decreases by 0.074 m/s2,0.05 m/s2,0.026 m/s2,0.018 m/s2 , respectively, and the maximum principal stress decreases by 4.3 kPa, 2.4 kPa, 1.2 kPa, 0.4 KPA respectively.

An approach for analysis of a single energy pile subjected to a horizontal load in sand

Many studies on horizontally loaded energy piles have tended to ignore the impact of axial frictional resistance in the analysis processes or lacked experimental validation. The effect of axial frictional resistance may be considered by conveniently calculating the frictional resistance and revealing the mechanism of axial frictional resistance. Our proposed displacement analysis approach takes into account pile-sand axial friction during heating. Validation was carried out through a centrifuge test case. Subsequent parametric analyses explored the influence of pile diameter and Young's modulus on the lateral response of the pile. Comparative results between the centrifuge test and proposed approach underscored its effectiveness in capturing the impact of friction resistance on energy piles during heating. The parametric analyses show that the increase in pile diameter from 0.5 m to 0.7 m and Young's modulus from 10 GPa to 20 GPa led to a decrease in normalized pile top displacement by 50.68% and 28.33%, a decrease in maximum soil pressure in front of the pile by 16.18% and 11.59%, and a decrease in maximum bending stress of the pile by 3.27% and an increase by 14.48%, respectively.

Optimization of functionally graded polycrystalline diamond compact based on residual stress: Numerical simulation and experimental verification

Polycrystalline diamond compact (PDC) is composed of a polycrystalline diamond layer with a tungsten carbide substrate, which is commonly used on drill bits. PDC bits are widely used in geological and petroleum drilling. There are frequently issues with failure, such as chipping of teeth during drilling, attributed to the residual stress within the PDC. Residual stresses arise from the difference in material properties between the polycrystalline diamond layer and the tungsten carbide substrate after sintering and cooling. To address the residual stresses inside the PDC, this research work optimized the design of a PDC with a functionally graded structure is reported in this paper. The effect of gradient structural parameters on the residual stresses of the PDC is analyzed using the finite element method. The results show that as the thickness of the gradient structural layer increases, the maximum residual tensile stress gradually decreases and stabilizes. Since the total thickness of the gradient structural layer is fixed, increasing the layer number (decreasing the thickness of the single layer) cannot reduce the maximum tensile stress, but it can minimize the sudden change of axial stress across the interface, thus resulting in less interface cracking. The optimum gradient structure design parameters are obtained and the optimal graded PDC is prepared via fused deposition modeling and sintering technology, resulting in a 62% reduction in maximum shear stress, a 70% decrease in maximum axial stress, and a 40% drop in maximum radial stress compared to conventional PDC. The accuracy of the finite element calculations is demonstrated by the Raman spectroscopy results. This work will provide a reliable guide for the design of functional graded structure PDCs and lay the foundation for their preparation and application.

Failure Analysis of Radio Frequency Coil in MRI System

Magnetic Resonance Imaging system and their working is itself very complex in nature. Any minor non-compliance will lead to failure of entire radio frequency coil. In this research paper, we are considering the failure of coil due to breakage of studs on outer frame during assembly. Seven Quality Control Techniques are used to find the root cause and check the effectiveness of implemented measures. Existing material shows extra stickiness during molding operation, that increases the stress within frame. Manual heat stacking process is used for insertion of metal insert, due to its uncontrollable measures, bulging was observed on studs. Sharp edges on the frame concentrate the stress and accelerate the breakage of stud while torquing screw. After research, we finalize alternative material which show better molding properties, introduced automation in heat stacking process and changed design of molding tool. In proto batch production, considerable change observed, like 18% decrease in maximum principal stress and 12% decrease in total deflection were observed.

Multiobjective optimisation of rail profile at high speed

In this paper, a multiobjective optimisation method considering the rail profile at high speed is presented. Based on nonuniform rational B-spline (NURBS) theory, a parameterised model of the rail profile is constructed to determine the variables. The wear index, wheel–rail lateral force and contact stress are selected as the objective function. Based on multibody dynamics theory is applied to establish the vehicle–track coupling dynamic model of the high-speed train CRH380A. An improved NSGA-II algorithm called CN-NSGA-II is proposed in this study. The multi-objective optimisation problem of rail profile is improved by the vehicle–track coupling dynamics model and CN-NSGA-II algorithm. The Pareto front solution is calculated, and the TOPSIS algorithm is used to select the optimal solution and obtain the optimised profile. The analysis of the objective function values of the CN60 profiles and the optimised profile indicate that the maximum wheel–rail lateral force of the left and right wheels of the steering wheelset decreases by 13.3% and 13.71%, the maximum contact stress decreases by 10.35% and 3.21%, and the maximum wear number decreases by 36.09% and 11.4%. The new optimised rail profile can effectively reduce the wheel–rail lateral force, contact stress and wear number in high-speed running conditions.

Simulation and analysis of sintering warping and thermal stress for a cermet half-cell of solid oxide fuel cells

Warping deformation often appears due to internal thermal stress generated during sintering process of solid oxide fuel cell (SOFC) functional layers composed of metal and ceramic composite materials. In this study, a model is developed for a half-cell of an anode-supported design SOFC to simulate warping displacement and thermal stress generated at the highest sintering temperature of 1673 K. A sensitivity analysis is further conducted, and the orthogonal experimental method is applied for parameter optimization. The predicted results reveal that the warping displacement is reduced by 64.3%, while the maximum thermal stress decreases by 55.8% as combined parameters are optimized. In addition, the effects of thickness and fillet treatment on the thermal stress and deformation are also investigated. It is found that the anode support layer is a dominant factor, and its thickness should not be less than 550 μm; the thickness of the electrolyte layer should be maintained at 20 μm; while the treatment of 10 mm fillets on the 10 × 10 cm2 scaled half-cells is favorite.

Numerical study on the effects of inner crucible window heights on the growth of silicon in a continuous Czochralski process

In order to improve the production efficiency of silicon materials, the effects of different inner crucible window heights on the growth of the continuous Czochralski silicon are numerically studied, and compared with the growth of the Czochralski silicon under the same conditions. The numerical results show that the existence of the inner crucible significantly changes the flow structure and velocity distribution of the silicon melt, intensifies the turbulence, and severely blocks the heat transfer of the side silicon melt, but also reduces the convexity of the c-m interface. With the decrease of the window height of the inner crucible, the heat blocking effect is stronger, but the crystal growth rate is increased. When ΔH = 20 mm, the crystal growth rate increases by 10 % compared with that of the single crucible structure, while the convexity of the crystal-melt interface and the maximum thermal stress decrease. Furthermore, considering the risk of silicon material being transported near the crystal-melt interface, adopting a lower window height is beneficial to the growth of continuous Czochralski silicon.

High temperature compression of Mo(Si,Al)[formula omitted]-Al[formula omitted]O[formula omitted] composites

The aim of this study was to investigate the effect on high temperature of mechanical properties of adding Al2O3 particles to polycrystalline Mo(Si,Al)2. Mo(Si,Al)2-Al2O3 composites, containing 0–25 wt% Al2O3 particles have been compression tested at 1300 °C, and the microstructure after deformation was studied using electron backscatter diffraction. It was shown that even small amounts (5 wt%) of Al2O3 particles resulted in a grain-refined material through inhibition of grain growth during sintering, which lead to lower flow stresses compared to the coarse-grained Al2O3-free material. The inverse grain size effect and post-test microstructure investigations suggest that creep-like deformation mechanisms dominate in fine grained Mo(Si,Al)2-Al2O3 composites at 1300 °C. In the materials containing 5–15 wt% Al2O3, the maximum stress decreased with increasing Al2O3 content. In materials with higher Al2O3 additions, the maximum stress increased with the Al2O3 addition, but did not reach the strength levels in the Al2O3-free reference material. It is suggested that the deformation behaviour is affected by electroplasticity effects as resistive heating was used. Electroplasticity contributes to the decrease in maximum stress observed in the lower Al2O3 containing materials, while this is outweighed by particle strengthening at higher Al2O3 contents.

Effect of Process Parameters on Stress Field of Laser Additive Manufacturing

In order to optimize the additive manufacturing process and find the process parameters affecting the mechanical properties of the parts, an additive manufacturing simulation model of Ti-6Al-4V titanium alloy was established, and the effects of ambient temperature, substrate thickness and wire temperature on the stress field and residual stress field were analyzed. The results show that the ambient temperature is inversely proportional to the residual stress of the cladding layer, while the substrate thickness and wire temperature are positively correlated to the residual stress of the cladding layer. When the ambient temperature increases from 0 °C to 600 °C, the maximum residual stress decreases by 36.0%, the maximum residual stress increases by 10.0% when the substrate thickness increases from 25 mm to 55 mm and the maximum residual stress increases by 7.48% when the temperature increases from 0 °C to 600 °C. The influence of the three parameters on the maximum residual stress is as follows: ambient temperature > substrate thickness > wire temperature. The research results can provide reference for stress control during actual manufacturing.

Fatigue assessment of U-rib full penetration welded joints based on local methods

Experimental and numerical methods were used to carry out fatigue assessment of double-sided full penetration U-rib welded joints with different deck thicknesses in Orthotropic Bridge Decks (OBD). The local stress field analysis was conducted by the finite element method. S-N curves for different thicknesses can be obtained based on fatigue test results. The Nominal Stress (NS) method, the Effective Notch Stress (ENS) method, and the Theory of Critical Distances (TCD) were applied to estimate the fatigue life. The feasibility of these three approaches was validated by fatigue test results. The results show that two types of fatigue crack initiation sites (inner and outer weld toes) and typical smooth and rough regions are found. The maximum principal stress decreases by about 30% when the deck thickness increasing from 14 mm to 18 mm, while the fatigue life increases by 6–11 times for different stress ranges. The stress concentration factors (SCFs) for U ribs with 14 mm, 16 mm, and 18 mm deck thicknesses are 2.71, 3.16, and 3.15, respectively. Double-sided U ribs welded joints with thicker decks have better fatigue performance. All predicted results using the NS method and the ENS method are greater than the FAT71 and FAT225 fatigue curves, respectively. The Point Method (PM) and Line Method (LM) in the form of TCD are found to be successful in predicting the fatigue life and recommended to fatigue assessment for double-sided welded U-ribs.

Compression behavior of confined circular reinforced concrete with spiral CFRP rope with different slenderness ratios

NSM-CFRP strip cannot be wrapped around the column, the necessity for flexible near-surface mounted carbon fiber reinforced polymer (NSM-CFRP) material has recently arisen. Under concentric compression stress, twelve circular reinforced concrete columns (RC) with three slenderness ratios (17.3, 23.8, and 28.1) in addition to the spacing between ropes were investigated to assess the behavior of confined RC columns using NSM-CFRP rope. The results showed that the load capacity of RC columns was increased by using the NSM-CFRP rope and decreasing the spacing between the NSM-CFRP ropes. Furthermore, when the slenderness ratio is decreased, the load capacity of columns increases. Specimens with heights of 800 mm, 1100 mm, and 1300 mm reinforced with 150 mm spacing between CFRP ropes had a greater increase in capacity (3.3 times, 1.6 times, and 1.97) than control specimens of each height. The confinement technique using spiral CFRP rope at 150 mm spacing has the greatest impact on the load-carrying capacity of the RC column. Additionally, confining the RC column with spiral CFRP rope at a 150 mm spacing enhanced the bearing load capacity of the RC column with the lowest slenderness ratio more than the other slenderness ratios. Finally, when the slenderness ratio increases, the bearing load capacity and axial strain corresponding to the maximum axial stress decrease. The slenderness ratio had the greatest impact on the behavior of the RC column when there was a higher amount of CFRP rope or when the spacing between CFRP ropes was the lowest.

Experimental and simulation study on heat transfer characteristics of aluminium alloy piston under transition conditions

In order to explore the thermal load change of the diesel engine piston under transitional conditions, and the influence of the position of cooling gallery on the heat transfer characteristics of the piston. An off-road high-pressure common-rail diesel engine is chosen as the research object. The sequence coupling method is used to establish the fluid–solid coupling heat transfer simulation model of the piston-gallery under the transition conditions of cold start, urgent acceleration and rapid deceleration. The Pareto optimization algorithm is introduced to optimize the position of the cooling gallery to reduce the maximum temperature and maximum thermal stress of the piston. The results show that the maximum temperature of the piston can be reduced by reducing the distance between the cooling gallery and the throat area under the maximum torque condition, and that the maximum thermal stress of the piston can be reduced by reducing the distance between the cooling gallery and the throat area or by increasing the distance between the cooling gallery and the ring area. Compared with the original design, the maximum temperature of Design A decreases by 1.28 °C while the maximum thermal stress decreases by 2.07 MPa. The maximum temperature and maximum thermal stress of Design B decreases by 0.22 °C and 0.5 MPa, respectively. The maximum thermal stress of Design C decreases by 2.67 MPa when the maximum temperature increases by 1.15 °C. The maximum change in temperature of the three typical designs and the original design of the piston throat under cold start, urgent acceleration and rapid deceleration conditions reached 207.29 °C, 136.78 °C and 9.89 °C, and the maximum change of thermal stress reached 8.62 MPa, 20.43 MPa, 4.08 MPa, respectively. The maximum change in temperature of the piston first ring groove under cold start, urgent acceleration and rapid deceleration conditions reached 172.00 °C, 83.52 °C and 7.36 °C, and the maximum change in thermal stress reached 22.96 MPa, 43.10 MPa, 5.72 MPa, respectively. The conclusions obtained can provide boundary conditions for further study of the thermal load change law of the same type of pistons, and also provide a theoretical basis for diesel engine piston structure optimization and the performance improvement.

Research on process optimization and rapid prediction method of thermal vibration stress relief for 2219 aluminum alloy rings

Abstract 2219 aluminum alloy rings are important part of liquid cryogenic rocket fuel tanks. Residual stress is inevitably introduced in the forming process of the rings due to the nonlinear thermomechanical coupling conditions, which will affect its mechanical properties, fatigue properties, corrosion resistance, and dimensional stability. Thermal vibratory stress relief (TVSR) has great potential in reducing residual stress, and process optimization of TVSR is necessary to further improve its application, but it is rarely reported. In this study, process optimization of roll formed 2219 aluminum alloy rings is conducted. The influence of vibration amplitude, vibration time, vibration frequency, heating time, holding time, and cooling time on TVSR treatment are investigated. Results show that the maximum equivalent residual stress of 2219 aluminum alloy rings can be reduced by 93.6% after optimized TVSR treatment. With the increase in vibration time, heating time, holding time, and cooling time, the maximum equivalent stress decreases. However, the increase in the vibration amplitude results in an increase in the maximum equivalent stress. Further, a genetically optimized artificial neural network intelligent optimization algorithm is applied to quickly predict the TVSR effect of 2219 aluminum alloy rings.

Titanium alloy piston thermo-mechanical coupling simulation and multi-objective optimization design

To solve the problem between temperature and thermal stress of a titanium alloy piston, a multi-objective optimization method combined response surface methodology and experiment design is performed to calculate an optimal design of the titanium alloy piston. Firstly, the thermo-mechanical coupling analysis, static and dynamic characteristics analysis are carried out. The analysis results show that the thermal load has a significant influence on the piston. Secondly, the five dimensional parameters are chose as the design variables through sensitivity analysis. The piston thermo-mechanical coupling stress, deformation, mass, and the first ring groove are selected as the objective functions. By using the optimal space-filling design method, the sample points between design variables and objective functions are gained. Then, the mathematical relationship between them is obtained by the response surface method. Finally, the multi-objective genetic algorithm is employed to optimize the mathematical model. After optimization, the maximum coupling deformation decreases by 3.05%, the maximum coupling stress decreases by 27.85%, the mass reduces by 5.46%. The maximum temperature of the first ring groove reduces by 12.54%. This study can provide a reference for the piston optimization design.

Study on Deformation and Fracture Evolution of Underground Reservoir Coal Pillar Dam under Different Mining Conditions

Coal mine underground reservoir water storage technology is an effective technical way to achieve high efficiency of coal mining and protection of water resources. The stability of coal pillar dam plays a decisive role in the safe and stable operation of underground reservoirs. Mining of adjacent working faces and long-term water erosion are the main influencing factors of stability of coal pillar dam. In this paper, a fluid-solid coupling calculation model for the deformation and evolution of coal pillar dam was established by FLAC3D numerical simulation software and the underground brine reservoir of Lingxin Coal Mine of Shenning group as an engineering background. The paper studied systematically the deformation, failure, and stress evolution of the dam with coal pillars soaked in water for a long time under different working face inclining length, coal pillar width, mining height, and water pressure. The simulation results showed that the degree of deformation and failure of the coal pillar dam continued to increase with the continuous advancement of the working face. The plastic zone of the coal pillar dam was increased by approximately 23.53%, the maximum vertical stress was increased by approximately 95.78%, and the maximum vertical deformation was increased by approximately 68.18%. The influence of each factor on the deformation and failure of overburden strata is quite different. The development range of plastic zone, the maximum vertical stress, and the maximum vertical deformation were increasing with the increased of working face inclined length and mining height. The increasing width of coal pillar would lead to the decrease of maximum vertical stress. The increase of water pressure would lead to the decrease of maximum vertical deformation. It can be seen that the inclined length of the working face is the main factor affecting the deformation and failure of the coal pillar dam. Coal pillar width and mining height are the main factors affecting the development of plastic zone. This study reveals the law of deformation and fracture evolution of coal pillar dam under different mining conditions, which can provide a reference for the design of coal pillar dam of coal mine underground reservoir.