Stacking Angles Research Articles

Prediction and calibration of black soil modeling parameters based on response surface methodology and machine learning algorithms

Five machine learning algorithms Decision Tree, Random Forest, Support Vector Machine (SVM), KNN, and XG Boost were used to calibrate the discrete element contact parameters of the black soil by combining the measured data on the black soil and the simulated pile load test. Firstly, the physical parameters of the black soil and the angle of stacking were determined based on physical tests. Next, Plackett-Burman tests were carried out and the following important parameters were obtained: black soil–black soil static friction coefficient, black soil–black soil rolling friction coefficient, and black soil–stainless steel rolling friction coefficient. The simulation parameters that significantly influenced the black soil stacking angles were designed for the steepest climbing tests to optimize a range of values of the significant parameters. Machine learning was performed to determine the optimal model based on the results of the response surface index results. The results show that the decision tree model has better predictive ability and stability for the stacking angle compared to Random Forest, SVR, KNN, and XG Boost models. The best combination of parameters for the black soil-black soil static friction coefficient was 0.956, the black soil–black soil rolling friction coefficient was 0.499, and the black soil–stainless steel rolling friction coefficient was 0.221. The simulation parameters can provide a reference for optimizing the simulation parameters for the subsequent soil particles.

An Adaptive Total Focusing Method for Ultrasonic Imaging ofArbitrarily Stacked Carbon Fiber-Reinforced Composites

The total focusing method (TFM) is increasingly recognized as a powerful ultrasonic imaging technique for the quality assessment and internal defect detection of carbon fiber-reinforced composites (CFRPs). Due to their unique structural and mechanical properties, CFRPs are widely used in aerospace, automotive, and energy industries, where stringent reliability and safety requirements demand advanced inspection techniques. However, the inherent characteristics of CFRPs, including high attenuation, high dissipation, and strong anisotropy, present significant challenges to ultrasonic imaging. These factors cause beam distortion, residual artifacts, false images, and low signal-to-noise ratios (SNR), making it difficult to achieve accurate imaging and detection of internal defects. To address these challenges, this study proposes an adaptive TFM method specifically designed for arbitrarily stacked CFRPs. The method begins by characterizing the anisotropic acoustic properties of CFRPs, which arise from their layered structure and the orientation-dependent stiffness of the carbon fiber plies. A stiffness matrix for CFRPs with arbitrary stacking angles is derived based on the mechanical constitutive relations of composite materials and a coordinate transformation matrix. The anisotropic acoustic velocity distributions are then computed using the Christoffel equation. These theoretical calculations are validated through experimental measurements of the actual anisotropic acoustic velocities in CFRP laminates. Comparisons between the theoretical and measured values demonstrate the accuracy and reliability of the proposed velocity modeling approach. The adaptive TFM method incorporates the obtained anisotropic velocity matrices and the stacking angles of the CFRP laminates to correct the time delay laws used in TFM imaging. To validate the effectiveness of the proposed method, experiments were conducted using CFRP laminate samples containing flat-bottom hole defects. The imaging results demonstrate that the adaptive TFM method achieves a substantial improvement in SNR and more precise delineations of defects compared to traditional TFM approaches. This work establishes a foundation for the development of high-precision ultrasonic inspection technologies tailored to the unique challenges posed by anisotropic composite materials, which have significant implications for quality assurance and reliability evaluation in industries that rely on CFRPs.

Magnetic Moment and Spin-State Transitions in Twisted Graphene Nanostructures.

The emergence of magnetic moments and spin-state transitions in the AA-stacking regions of twisted graphene nanoflakes is analyzed by using Density Functional Theory (DFT). Systems of different sizes (C192H48, C300H60, and C432H72) are employed to model some possible stacking angles. Potential Energy Curves (PECs) are computed for different interlayer distances and twist angles, revealing that the triplet ground state appears only in the repulsive region of the PEC, with the transition distance depending on the flake size. The results indicate that interlayer repulsion and twisted angle play significant roles in determining magnetic properties, while spin density analysis confirms that edge effects and AB-region confinement are fundamental to the emergence of magnetic moments in twisted graphene bilayers.

Establishment of Whole-Rice-Plant Model and Calibration of Characteristic Parameters Based on Segmented Hollow Stalks

To address the limitations of the current discrete element model of rice plants in terms of accurately reflecting structural differences and threshing characteristics, this study proposes a whole-rice-plant modeling method based on segmented hollow stalks and establishes a whole-rice-plant model that accurately represents the bending and threshing characteristics of the actual rice plant. Initially, based on the characteristics of the rice plant, the rice stalk was segmented into three sections of hollow stalks with distinct structures—namely, the primary stalk, the secondary stalk, and the tertiary stalk—ensuring that the model closely resembles actual rice plants. Secondly, the mechanical and contact parameters for each structure of the rice plant were measured and calibrated through mechanical and contact tests. Subsequently, utilizing the Hertz–Mindlin contact model, a multi-dimensional element particle arrangement method was employed to establish a discrete element model of the entire rice plant. The bending characteristics of the stalk and the threshing characteristics of the rice were calibrated using three-point bending tests and impact threshing tests. The results indicated calibration errors in the bending resistance force of 4.46%, 3.95%, and 2.51% for the three-section stalk model, and the calibration error for the rice model’s threshing rate was 1.86%, which can accurately simulate the bending characteristics of the stalk and the threshing characteristics of the rice plant. Finally, the contact characteristics of the model were validated through a stack angle verification test, which revealed that the relative error of the stacking angle did not exceed 7.52%, confirming the accuracy of the contact characteristics of the rice plant model. The findings of this study provide foundational models and a theoretical basis for the simulation of and analytical applications related to rice threshing and cleaning.

Enhanced second harmonic generation in a Fdd2 polymorph of C12H8N2O4Zn for UV nonlinear optical applications.

The quest for novel nonlinear optical (NLO) polymorphs is pivotal for advancing laser technology and frequency conversion applications. We present a detailed study on the synthesis and properties of the Fdd2 polymorph of C12H8N2O4Zn, which exhibits an enhanced second harmonic generation (SHG) effect, 0.3 times that of KDP, nearly 8-fold higher than the P43212 phase. This improvement is attributed to an increased [ZnN2O4] polyhedral stacking angle and structural distortion in the Fdd2 phase. Our findings underscore the importance of polymorphs in optimizing NLO properties and position the Fdd2 phase as a promising candidate for ultraviolet NLO applications.

基于 DEM 的类球型大豆离散元仿真参数标定与试验

This paper focuses on the lack of spherical-like soybean simulation parameters when guiding the optimization and design of agricultural machinery and equipment through discrete element simulation. The spheroidal soybean variety SN29 was used as a study subject; the intrinsic properties and physico-mechanical properties of the spherical soybean were determined through actual measurements and the simulation of spherical-like soybean particles with Hertz-Mindlin (no-slip) as the contact model was established. The collision recovery, static, and rolling friction coefficients of the spherical-like soybean and acrylic sheet material were measured by the natural drop and inclined plane methods, combined with discrete element simulation and bench experiments. They were 0.474, 0.496, and 0.0361, respectively. The relative errors between the measured stacking angles and the simulated stacking angles were used as indicators, and the contact parameters between the particles were used as variables for the design of the steepest climb experiment. The collision recovery coefficient, static friction coefficient, and rolling friction coefficient between spherical-like soybean particles were determined to be 0.35, 0.30, and 0.074, respectively, by orthogonal rotational combination experiment and multi-objective optimization. The relative error between the simulated and measured stacking angles was only 1.09%, as verified by the experiment. This proves that the discrete element simulation parameters of the studied spherical-like soybean can reflect its real characteristics and be used as the parameter basis for discrete element simulation.

A Comparative Analysis of Buckling Pressure Prediction in Composite Cylindrical Shells Under External Loads Using Machine Learning

Composite materials are increasingly utilized in engineering due to their superior properties such as strength, flexibility, and corrosion resistance. However, accurately predicting the buckling pressure of composite cylindrical shells under external loads remains challenging due to the complexities introduced by various stacking methods. This study addressed this challenge by integrating advanced machine learning techniques with simulation-based data generation through finite element analysis (FEA). A comprehensive dataset comprising 1369 simulation results was generated using ANSYS ACP, focusing on cylindrical shells modeled with an 8-mm-thick filament winding technique and T700 material. The stacking angles ranged from −90 degrees to 90 degrees in 5-degree increments. Stacking configurations (inputs) and their corresponding buckling strength (outputs) were generated using ANSYS ACP. Machine learning models, including linear regression, elastic net, polynomial regression, random forest, support vector regression, XGBoost regression, and artificial neural networks, were implemented using Python 3.8 and Scikit-learn (version 0.24.2). A comparative analysis of these methods revealed their model performance, providing insights into the most effective approaches. Additionally, the accuracy of these models was then evaluated on previously unseen input data, allowing for a comparison of their out-of-sample accuracy. The results demonstrated that the random forest model and XGBoost regression achieved superior accuracy with minimal prediction errors. The study highlights the critical role of machine learning in predicting buckling pressure, which is essential for ensuring structural integrity and optimizing performance in marine engineering and other applications involving composite materials.

基于离散元的小白菜种子仿真参数标定与试验

Physical property parameter measurements and simulation model parameter calibrations of Pak Choi seeds were conducted to address the lack of accurate parameters for discrete elemental seed discharging simulation tests in the seed-metering device. Firstly, physical tests were utilized to determine the basic physical parameters and contact parameters of Pak Choi seeds. The results of these physical tests served as the basis for determining the range of simulation parameters. The Plackett-Burman test was employed to screen out factors that significantly affected the simulated angle of repose from the test parameters, including static friction coefficient between Pak Choi seeds-Pak Choi seeds and rolling friction coefficient between Pak Choi seeds-Pak Choi seeds. The optimal interval of these two factors was determined using the Steepest Climb Test. Subsequently, the regression equation between the significance parameters and the angle of repose was obtained through the Central Composite Designs test, and the best parameter combinations were obtained with the measured stacking angle of 24.3° as the optimisation target value: Pak Choi seeds-Pak Choi seeds static friction coefficient of 0.486, Pak Choi seeds-Pak Choi seeds rolling friction coefficient of 0.104. Finally, simulation and bench comparison tests were carried out for stacking angle and Pak Choi seed discharger performance evaluation. The relative error of the angle of repose was found to be 0.288%, while average relative errors for qualified sowing rate, replanting rate, and missed sowing rate were all less than 5%. These results demonstrate that calibrated Pak Choi seed simulation parameters are reliable and can serve as a reference for design optimization of Pak Choi seed dischargers in academic research writing standards.

Tuning Van Der Waals Heterostructure of WS2/SrTiO3 Via in Situ Transmission Electron Microscopy

Monolayer two-dimensional (2D) materials have been widely researched and discussed in recent years, while multi-layers have received comparatively less attention. Nowadays, combining different materials to create heterostructures has become mainstream. In semiconductor industry, heterostructure can form devices such as lasers, light-emitting diodes, fast transistors and so on. Heterostructures can create well electronic properties by combining two different materials together. Therefore, heterostructures become a great tool to manipulate the electronic structures. In traditional heterostructures, the interfaces between two different materials are formed by covalent bonds, hence it requires similar lattice constants and structures. On the other hand, novel van der Waal heterostructures (vdW-heterostructure), formed by 2D materials, do not require the same strict similarity as traditional ones. VdW-heterostructures, which create 3D structures through van der Waals forces, provide a new perspective. In this study, we created a vdW-heterostructures by stacking tungsten disulfide (WS2) with single-crystal strontium titanate, SrTiO3 (STO), shown in Figure 1a,b. The crystalline atomic-layer WS2 and STO were synthesized by chemical vapor deposition (CVD) and pulsed laser deposition (PLD), respectively. They are analyzed by high-resolution transmission electron microscope (HRTEM) shown in Figure 1c-h. Once the vdW-heterostructures are formed, we conducted in situ heating by TEM. Through the advanced in situ technique, we observed the change of the twisted stacking angle by heating the vdW-heterostructure. Ultimately, the lattices will shift and rotate, minimizing the free energy, so that the vdW-heterostructure will be aligned and formed epitaxially. In addition, we utilized atomic resolution scanning transmission electron microscope (STEM) to identify the stacking images and the moiré pattern of the vdW-heterostructure. During the rotation, we can observed different moiré patterns by various twisted stacking angles. These different moiré patterns can produce different electrical properties, which can be applied to advanced semiconductor devices. Keywords: high-resolution TEM/STEM, in situ heating, 2D materials, van der Waal heterostructures, moiré pattern Figure 1. The vdW-heterostructure of STO/WS2. a) The diagram showing that the formation process of WS2/STO vdW-heterostructures which have different twisted stacking angles. b) The low-magnification SEM image showing that the single crystal STO thin film is transferred onto the TEM heating chips. The circles in the middle are the observation windows for transmission electrons. c-e) HRTEM images. f-g) Diffraction patterns of HRTEM. c,f) Single crystal STO thin film with d-spacing (1−10) = 0.284 nm. d,g) Monolayer single crystal WS2 with d-spacing (−110) = 0.274 nm. e,h) WS2(red)/STO(yellow) vdW-heterostructure with stacking angle 3.6°. Figure 1

Mechanical Characterization of GFRP Tiled Laminates for Structural Engineering Applications: Stiffness, Strength and Failure Mechanisms

This study investigates the mechanical properties of tiled laminates, frequently used in FRP bridges, and a completely new class of composites for which currently no experimental literature is available. In this paper, first a microscopic examination of laminates extracted from bridge deck flanges is performed, revealing complex multi-ply structures and tiled laminates in the transverse direction of the bridge deck. The subsequent fabrication of tiled laminates in the transverse (i.e., weak) and longitudinal (i.e., strong) span direction explores stiffness and strength characteristics depending on the stacking angle. It is observed that the stiffness in both directions is only slightly reduced with increasing stacking angles, reaching a maximum decrease of 10%, while the failure strength is significantly reduced, particularly with longitudinal tiling, dropping by approximately 70% for a 2° stacking angle. Transverse tiling demonstrates a more moderate 45% strength reduction due to the presence of some 90° plies. Given the small reduction in the stiffness and the fact that in many applications the design is mainly governed by serviceability (i.e., stiffness) requirements than strength, this strength reduction may be acceptable, considering other advantages of the concept. Additionally, this research sheds light on failure mechanisms, emphasizing the role of ply assembly in stress distribution and highlighting the importance of gradual ply ends in reducing strain concentrations. These findings provide valuable insights for optimizing tiled laminates in structural applications, ensuring their effective and reliable use.

Effect of stacking angles on crashworthiness of CFRP square tubes considering low-velocity impact damage

To enhance the residual energy‐absorption (EA) of low-velocity impact-damaged CFRP square tubes, this study investigates the influence of stacking angles on the damaged tubes' residual EA. Through simulation and theoretical analysis, a well-designed stacking angles is proposed to optimize the residual EA. Initially, a simplified method of low-velocity impact damage of composite materials is proposed, by which a discontinuous damage mechanics finite element model is established and experimentally verified. Subsequently, various layup sequences are examined, and their impact on energy absorption is evaluated using several performance indices, including initial peak load, average load, energy absorption, specific energy absorption, and crushing load efficiency. The findings demonstrate that the designed stacking angles significantly enhances the residual energy absorption of low-velocity impact-damaged square tubes. Moreover, the study verifies the efficacy of the stacking angles design by investigating actual damage conditions, encompassing factors such as damage size, location, and stress concentration.

Flow field analysis and particle erosion of tunnel‐slope systems under coupling between runoff and fast (slow) seepage

AbstractThe presence of particles on the surface of a tunnel slope renders it susceptible to erosion by water flow, which is a major cause of soil and water loss. In this study, a nonlinear mathematical model and a mechanical equilibrium model are developed to investigate the distribution of flow fields and particle motion characteristics of tunnel slopes, respectively. The mathematical model of flow fields comprises three parts: a runoff region, a highly permeable soil layer, and a weakly permeable soil layer. The Navier‒Stokes equation controls fluid motion in the runoff region, while the Brinkman‐extended Darcy equation governs fast and slow seepage in the highly and weakly permeable soil layers, respectively. Analytical solutions are derived for the velocity profile and shear stress expression of the model flow field under the boundary condition of continuous transition of velocity and stress at the fluid‒solid interface. The shear stress distribution shows that the shear stress at the tunnel‐slope surface is the largest, followed by the shear stress of the soil interface, indicating that particles in these two locations are most vulnerable to erosion. A mechanical equilibrium model of sliding and rolling of single particles is established at the fluid‒solid interface, and the safety factor of particle motion (sliding and rolling) is derived. Sensitivity analysis shows that by increasing the runoff depth, slope angle, and soil permeability, the erosion of soil particles will be aggravated on the tunnel‐slope surface, but by increasing the particle diameter, particle‐specific gravity, and particle stacking angle, the erosion resistance ability of the tunnel‐slope surface particles will be enhanced. This study can serve as a reference for the analysis of surface soil and water loss in tunnel‐slope systems.

Time-reversal symmetry breaking superconductivity between twisted cuprate superconductors.

Twisted interfaces between stacked van der Waals (vdW) cuprate crystals present a platform for engineering superconducting order parameters by adjusting stacking angles. Using a cryogenic assembly technique, we construct twisted vdW Josephson junctions (JJs) at atomically sharp interfaces between Bi2Sr2CaCu2O8+x crystals, with quality approaching the limit set by intrinsic JJs. Near 45° twist angle, we observe fractional Shapiro steps and Fraunhofer patterns, consistent with the existence of two degenerate Josephson ground states related by time-reversal symmetry (TRS). By programming the JJ current bias sequence, we controllably break TRS to place the JJ into either of the two ground states, realizing reversible Josephson diodes without external magnetic fields. Our results open a path to engineering topological devices at higher temperatures.

A Calibration of the Contact Parameters of a Sesbania Seed Discrete Element Model Based on RSM

In order to simulate and analyze the mechanized seeding process of sesbania seeds by using a discrete element method and improve the reliability of the discrete element simulation test, the contact parameters of sesbania seeds were calibrated in combination with the actual seed drop test and the simulated seed drop test. Through measurements, the intrinsic parameters of the sesbania seed were determined, and the discrete element simulation model of the sesbania seed was established. A measuring device that can simultaneously measure the resting angle and the stacking angle of the population was designed. The rest angle error and the stack angle error of the actual seed drop test and the simulated seed drop test were used as test indicators. The Plackett–Burman test screened out the contact parameters that had a significant effect on the test indicators. The response surface method (RSM) was used to carry out the three-factor quadratic rotation orthogonal combination test, and the mathematical regression model between the significant contact parameters and the test indexes was established. The optimal combination of contact parameters was determined using the multi-objective optimization method as follows: collision recovery coefficient between seeds of 0.463, static friction coefficient between seeds of 0.520, and rolling friction coefficient between seeds of 0.072. The discrete element model and calibration parameters of sesbania seeds were tested and verified using a fluted roller feed mechanism. The results showed that the average relative error between the measured value and the simulated value of the mass flow rate of the sesbania seeds was 2.74%, less than 5%, indicating that the discrete element simulation model of sesbania seeds and the calibration results of the contact parameters had high accuracy and reliability, which could be used for the discrete element simulation test of sesbania seeds.

Using transition density models to interpret experimental optical spectra of exciton-coupled cyanine (iCy3)2 dimer probes of local DNA conformations at or near functional protein binding sites.

Exciton-coupled chromophore dimers are an emerging class of optical probes for studies of site-specific biomolecular interactions. Applying accurate theoretical models for the electrostatic coupling of a molecular dimer probe is a key step for simulating its optical properties and analyzing spectroscopic data. In this work, we compare experimental absorbance and circular dichroism (CD) spectra of 'internally-labeled' (iCy3)2 dimer probes inserted site-specifically into DNA fork constructs to theoretical calculations of the structure and geometry of these exciton-coupled dimers. We compare transition density models of varying levels of approximation to determine conformational parameters of the (iCy3)2 dimer-labeled DNA fork constructs. By applying an atomistically detailed transition charge (TQ) model, we can distinguish between dimer conformations in which the stacking and tilt angles between planar iCy3 monomers are varied. A major strength of this approach is that the local conformations of the (iCy3)2 dimer probes that we determined can be used to infer information about the structures of the DNA framework immediately surrounding the probes at various positions within the constructs, both deep in the duplex DNA sequences and at sites at or near the DNA fork junctions where protein complexes bind to discharge their biological functions.

Optical properties and Landau quantisations in twisted bilayer graphene

ABSTRACT The optical properties and Landau quantisations in twisted bilayer graphene are investigated using a generalised tight-binding model that takes into account all interlayer and intralayer atomic interactions in the Moire superlattice. The system is a zero-gap semiconductor with double-degenerate Dirac-cone structures, and saddle-point energy dispersions appear at low energies for small twisting angles. The magnetic quantisation phenomena in this system are rich and unique, with Landau-level subgroups specified owing to specific Moire zone folding through modulation of the stacking angles. The Landau-level spectrum shows hybridised characteristics associated with those in monolayer, as well as AA and AB stackings. The detailed analysis explores the complex relations among the different sublattices on the same and different graphene layers.

Rapid acquisition method of discrete element parameters of granular manure and validation

Rapid acquisition method of discrete element parameters of granular manure and validation

Taguchi analysis of the tensile behaviour of unaged and hygrothermally aged asymmetric helicoidally stacked CFRP composites

Taguchi method was used to predict and optimize the effects of hygrothermal aging on the tensile behavior of asymmetric helicoidally stacked Carbon Fiber Reinforced Plastic (CFRP) composites. This research is in furtherance to the previous work, which dealt purely with experiments. MR70 12P carbon fiber epoxy prepreg sheets were manufactured into laminated composites comprising constant inter-ply pitch angles ranging from 0o to 30o. The composites were tested in tension as either dry unaged specimens or following hygrothermal aging in seawater at the constant temperatures of 40 oC and 60 oC for 2000 hrs. Optimizations were conducted based on Taguchi L18 orthogonal array considering two design parameters viz. inter-ply stacking angles and hygrothermal aging temperature. The result depicted that the combination of aging temperature (C) and stacking angles are major factors in determining the tensile behavior of composite materials (p = 0.011). The model explains 86.6% of tensile strength variability, with a predicted R-squared value of 93.04%. The model’s robustness is supported by the adjusted R-squared value of 77.6%. Analysis of variance shows that inter-ply stacking angles are the main significant factor affecting the tensile behaviors at a 95% confidence level. A confirmation test was carried out to validate the optimized results and it was found that there were improvements in S/N ratios from initial to optimal setting.

Optimization of viscoelastic behaviors of bioinspired asymmetric helicoidal CFRP composites using Taguchi Method

The dynamic mechanical properties play an important role in the selection of suitable materials in the manufacturing wing of aircraft and wind turbine blades. In this paper, the standard Taguchi method was used to examine the effect of inter-ply stacking angles of 0° (UD), 0/90° (cross-ply), 5°, 15°, 10°, 20°, 25° 30° and aging temperature (ambient temperature, 40o, 60o) on the dynamic mechanical properties of bioinspired asymmetric helicoidal Carbon Fiber Reinforced Plastic (CFRP) composites. The standard Taguchi’s L18 was used. The signal-to-noise ratio and analysis of variance were introduced to analyze and estimate the optimal combination parameters. The results show the dynamic mechanical properties are linearly correlated to the fiber architecture and aging temperature. Analysis of variance (ANOVA) indicates that inter-ply stacking angles (15°, and 20°) and aging temperature (40o, 60o) are the main significant factors affecting the dynamic mechanical values at a 95% confidence level. Inter-ply stacking angles are finally noted as critical factors affecting the extent of macromolecular mobility within helicoidally stacked continuous fiber CFRP composites. A confirmation test validated the optimized results and it was found that there were improvements in S/N ratios from initial to optimal setting. The experimental and expected results are very close, with an error ratio not exceeding 5%.

Probing the Twist-Controlled Interlayer Coupling in Artificially Stacked Transition Metal Dichalcogenide Bilayers by Second-Harmonic Generation.

Interlayer coupling plays a critical role in the electronic band structures and optoelectronic properties of van der Waals (vdW) materials and heterostructures. Here, we utilize optical second-harmonic generation (SHG) measurements to probe the twist-controlled interlayer coupling in artificially stacked WSe2/WSe2 homobilayers and WSe2/WS2 and WSe2/MoS2 heterobilayers with a postannealing procedure. In the large angle twisted WSe2/WSe2 and WSe2/WS2, the angular dependence of the SHG intensity follows the interference relations up to angles above 10°. For lower angles, the SHG is significantly suppressed. Furthermore, for the twisted WSe2/MoS2 the SHG intensity largely deviates from the coherent superposition model and shows consistent quenching for all the stacking angles. The suppressed SHG in twisted transition metal dichalcogenide (TMDC) bilayers is predominantly attributed to the interlayer coupling between the two adjacent monolayers. The evolution of the interlayer Raman mode in WSe2 demonstrates that the interlayer coupling in the twisted WSe2/WSe2 and WSe2/WS2 is highly angle-dependent. Alternatively, the interlayer coupling generally exists in the twisted WSe2/MoS2, regardless of the different angles. The interlayer coupling is further confirmed by the quenching and red-shift of the photoluminescence of WSe2 in the twisted TMDC bilayers. Combined with density functional theory calculations, we reveal that the stacking-angle-modulated interlayer coupling originates from the variation of the interlayer spacing and the binding energy in the twisted TMDC bilayers.