Biaxial Model Research Articles

Biaxial steel plated concrete constitutive models for composite structures: Implementation and validation

The Steel-plated Concrete (SC) technique is an alternative construction technique with faster onsite construction speed, reduced construction time, and increased structural performance. Aiming to predict the force transfer mechanism of SC elements, an innovative constitutive model package is proposed by implementing experimental-based biaxial steel plate concrete models into the nonlinear finite element (FE) model “Membrane Model of SC (MM-CS).” First, the formulation and implementation of the MM-SC is illustrated in detail, including the equilibrium and compatibility equations and the implementation of constitutive models. Subsequently, various experimental data of SC members are selected and simulated using the proposed MM-SC model. In this research, two types of structures, SC panels and framed SC shear walls, and three types of loading conditions, including uniaxial compression, pure shear, and combined axial-flexural-shear tests, are analyzed respectively. Good agreements were obtained between the reported results and the FE simulation results in terms of yield capacity and ultimate capacity, proving the reliability of the implemented analytical constitutive material models and the biaxial membrane model formulations.

Residual stress determination in thin films by X-ray diffraction and the widespread analytical practice applying a biaxial stress model: An outdated oversimplification?

Compressive stresses are commonly desired in thin films and the stress state in layers and coatings is in general evaluated assuming a biaxial nature of stress. But how thin is thick enough, or how many atom layers are necessary until this model assumption fails and a hydrostatic term joins in? In order to provide an answer molybdenum has been magnetron sputtered on display glass in layer thicknesses from 100 nm up to 2000 nm and afterwards investigated by X-ray diffraction to determine the residual stress state in the [110] fiber-textured sputtered films. It will be demonstrated that the use of a biaxial stress model might only be justified for thin layers if at all.

A novel family of multiple springs models suitable for biaxial rate-independent hysteretic behavior

This paper presents a novel family of multiple springs models capable of reproducing the nonlinear response typical of mechanical systems and materials having a biaxial kinematic rate-independent hysteretic behavior. In such a formulation, the generalized force vector, representing the output variable, is computed by summing the contribution of n springs, respectively made up of a nonlinear elastic spring in parallel with a rate-independent hysteretic one. In particular, the generalized force of each spring is computed as a function of the related generalized displacement and history variable. Two isotropic biaxial hysteretic models are derived from the proposed general formulation: the Multiple Springs Bilinear Model and the Multiple Springs Exponential Model. The former is an algebraic model that is illustrated to clearly explain the meaning of the parameters and variables adopted in the formulation. Conversely, the latter is a transcendental model that is presented not only to demonstrate the potentiality of the family in terms of accuracy and computational efficiency, but also to show the possibility of developing models that can reproduce different types of biaxial hysteretic behavior with few parameters having a clear mechanical significance. Such a sophisticated model is validated through numerical and experimental tests.

Steering single-element lead zirconate titanate ultrasound transducers using biaxial driving

Previous work has shown that biaxial driving using two phase-offset orthogonal electric fields (propagation and lateral) improves the efficiency of ferroelectric materials by reducing coercivity and, hence, energy dissipation. In the current investigation, we demonstrated the capability of the biaxial method to steer ultrasound waves in single-element piezoceramic transducers made of prismatic lead zirconate titanate (PZT). We conducted finite element analysis simulations for 133 kHz (model 1) and 470 kHz biaxial (model 2) transducers models. We performed experimental validation with biaxially driven single-element transducers (n = 3) operating at an average frequency of 131 kHz with the same characteristics as model 1. For both models, we found non-symmetric steering that was a function of both the phase and power of the second electric field. At a constant electrical power (1 W) on the propagation electrodes, simulations for the 133 kHz model predicted maximal steering of 10.3°, 22.6°, and 30.9° for lateral electrode powers of 0.1 W, 0.5 W, and 1.0 W, respectively. Experimentally, for model 1, the maximal steering was 11.7° ± 1.9°, 23.5° ± 3.5°, and 30.2° ± 4.4° for the lateral electrode powers of 0.1 W, 0.5 W, and 1.0 W, respectively. Simulations for the 470 kHz model predicted maximal steering of 8.8°, 16.1°, and 27° for lateral electrode powers of 0.1 W, 0.5 W, and 1.0 W, respectively. Simulations showed that the cause of the steering asymmetry was a non-uniform shear deformation associated with the slightly off-resonance lateral electric field driving frequency. This is the first demonstration of ultrasound steering using a single-element transducer, which can have important applications for ultrasound focusing with phased arrays.

Biaxial reinforced concrete constitutive models for implicit and explicit solvers with reduced mesh sensitivity

A new set of constitutive models named TsingHua University Concrete 2D (THUC2) is developed for use in ABAQUS. THUC2 has reduced mesh sensitivity and is based on the decoupling assumption and the fixed-angle crack assumption in order to consider the pinching effect, confinement, strength degradation, and shear softening of concrete. In the developed biaxial reinforced concrete models, the uniaxial model is first established, and the biaxial model is subsequently assembled from the uniaxial model. First, the proposed uniaxial constitutive model of concrete is reported. The mesh sensitivity of the model is reduced by adjusting the descending branch of the concrete model based on mesh size. Second, a total of five biaxial constitutive models of concrete are reported to cover a wide range of simulation requirements in engineering design. Third, the numerical implementation of the proposed concrete model in both ABAQUS implicit and explicit solvers is discussed. Subsequently, the modified two-way fixed angle crack model is validated by monotonic and hysteretic panel tests. The FE model exhibits little mesh sensitivity when the element number increased from 4 to 400. The developed model accurately predicts the pinching effect and the softening effect of the panels. Finally, previous tests on two nuclear containment vessels under lateral loads are simulated, and the modified two-way fixed angle crack model demonstrates adequate accuracy in terms of predicting the initial stiffness, ultimate capacity, and pinching effect. The proposed subroutine package for simulating RC members includes the dominant mechanical behaviors of concrete and can be adopted for high-efficiency simulation of RC shear wall structures.

Durability and Compression Properties of High-Strength Concrete Reinforced with Steel Fibre and Multi-walled Carbon Nanotube

High-strength concrete (HSC) reinforced with steel fibre (SF) and carbon nanotube (HSCRSC) is a new type of high-strength composite concrete with good fluidity, high strength, toughness, durability and other remarkable advantages. HSCRSC can be widely used in underground structures, such as wellbores. In this study, HSCs ranging from 70 to 100 MPa were designed, and the effects of fibre on the performance of the HSCs were compared and analysed through single-doped and double-mixed SF and multi-walled carbon nanotubes. Results showed that the fibre effectively improved the uniaxial and multiaxial compressive strengths and durability of HSCs and changed the failure mode from brittle to ductile, especially in the case of multiaxial compression failure. HSCs remained intact, but the plain concrete specimens had fractured forms, such as flakes, columns and layers. Moreover, the ultimate strength of the biaxial compression was between 1.10 and 1.39 times higher than that of the uniaxial compression, satisfying the Kufer–Gerstle criterion. The ultimate strength of the triaxial compression was between 1.24 and 2.55 times higher than that of the uniaxial compression, adhering to the Willam–Warnke meridian criterion. The modified B3 model met the prediction accuracy of shrinkage and creep for HSC and surpassed the biaxial and triaxial compression ultimate strength models provided in this study. The absolute value of the relative error was less than 6%, indicating that the model and test data were reliable. All test results showed that HSCRSC exhibited satisfactory comprehensive performance.

Experimental and numerical studies on the reinforcing mechanisms of geosynthetic-reinforced granular soil under a plane strain condition

Geosynthetics have been widely used in the construction of reinforced soil structures and yet the reinforcing mechanisms of geosynthetics have not been fully understood. Eight biaxial compression model tests of geosynthetic-reinforced soil (GRS) were conducted in this study under a plane strain condition to investigate the reinforcing mechanisms of geosynthetics. Membrane was used as reinforcement material and aluminum rods were used to simulate the granular backfill soil. Three influencing factors were considered in the model tests including reinforcement spacing, reinforcement stiffness, and gradation of backfill soil. This study also conducted a numerical analysis using a discrete element method (DEM) model. The DEM model was calibrated and verified by geosynthetic tensile test, angle of repose test, biaxial test, and model test results of the GRS masses. The piecewise linear model was used in the numerical model to simulate the nonlinear characteristics of the geosynthetic under tensile load. A parametric study was conducted to obtain further detailed insights into the reinforcing mechanisms of geosynthetics. Results of the model tests and the numerical simulations indicated that reinforcement spacing had strong effects on the behavior of the GRS mass. The dilation of the backfill soil was suppressed by reinforcement and the suppression was enhanced by increasing reinforcement stiffness and reducing reinforcement spacing. The reinforcement spacing played a more important role in the behavior of the GRS than the reinforcement stiffness. Geosynthetics reinforcement could restrain the development of vertical settlements along the height of the GRS mass. In addition, the geosynthetic reinforcement had a function of dispersing vertical applied pressure and the stress induced by loading was more uniformly distributed in the GRS mass as compared with unreinforced cases. Increasing reinforcement stiffness had little effect to improve the dispersion function of geosynthetics. The reinforcing effects in the GRS mass backfilled with soil of low strength were more significant compared to that in the GRS mass backfilled with soil of high strength.

Smooth Nonlinear Hysteresis Model for Coupled Biaxial Soil-Pipe Interaction in Sandy Soils

Pipelines as infrastructure components are very vulnerable to geohazard-induced ground deformation and failure. Soil–pipe interaction (SPI) thus is very important for the assessment and design of resilient pipeline systems. Previous work on SPI modeling has been based on crude assumptions, such as representation of the soil as uncoupled three-dimensional bilinear springs, and quasi-static loading conditions. This paper proposes a simplified macroelement designed to capture the effects of dynamic SPI in cohesionless soils subjected to arbitrary loading normal to the pipeline axis. First, we present the development of a uniaxial hysteresis model that can capture the smooth nonlinear reaction force-relative displacement curves (FDCs) of SPI problems. Using the unscented Kalman filter, we derived the model parameter κ that controls the smoothness of transition zone from linear to plastic using published empirical and experimental data. We extended this uniaxial model to biaxial loading effects, and showed that the macroelement can capture effects such as pinching and shear–dilation coupling. The model input parameters were calibrated using finite-element (FE) analyses validated by experiments. The FDCs of the biaxial model were verified by comparison with FE and smoothed-particle hydrodynamic (SPH) simulations for different loading patterns: cyclic uniaxial, 0-shaped, 8-shaped, and transient loading. Accounting for smooth nonlinearity, hysteresis, pinching, and coupling effects, the proposed biaxial macroelement showed good agreement with FE and SPH analyses, while maintaining the computational efficiency and simplicity of beam on nonlinear Winkler foundation models, as well as a small number of input parameters.

A path dependent constitutive model for CFFT column

Confinement, such as hollow-steel tube (HST) and fibre-reinforced polymer (FRP) tube, can improve not only the loading capacity of concrete structures, but also ductility. Compared with HST, FRP tube has stronger flexural and tensile strength, as well as resistance against corrosion. It is also lighter and more durable. Thus, concrete-filled-FRP-tube (CFFT) column is ideal for new buildings’ construction for improving safety, prolonging design life and enhancing sustainability. However, their experimental studies are relatively limited, and the existing stress-strain models cannot capture their full range behaviour. Herein, to understand more thoroughly and simulate the uni-axial performance of CFFT columns, a database collecting 28 CFFT columns test results is assembled for establishing a new stress-strain model that comprises the following 4 parts: (1) A model of hoop strain set up by the authors taking into account the effects of concrete splitting cracks; (2) An adjusted constitutive model of actively confined concrete incorporating confining stress path dependent effect; (3) Bi-axial stress model of FRP tube; (4) A model addressing the compatibility condition of concrete and FRP tube. Finally, the theoretical axial stress-strain curve matches very well with those experimental curves of CFFT columns, which verifies the validity of the model proposed in this study.

In-plane optical anisotropy and SERS detection efficiency of self-organized gold nanoparticles on silicon nanoripples: Roles of growth angle and postgrowth annealing

In this work, we report on substrate morphology-mediated plasmonic anisotropy and surface-enhanced Raman scattering-based molecular detection efficacy of oblique angle grown self-organized gold nanoparticles (Au-NPs) on ultralow energy ion-beam fabricated nanoscale rippled-Si (R-Si) substrates. To study the effect on plasmonic field coupling, the shape of Au-NPs is tuned from elongated to spherical ones by varying the growth angle leading to a change in the interparticle gap. Following this, postgrowth annealing of Au-NP arrays is carried out to change the shape and size of Au-NPs via Ostwald ripening process. The optical anisotropy is measured using generalized ellipsometry, while dielectric functions of Au-NP arrays are calculated using a biaxial layer model by fitting the Jones matrix elements. A stronger plasmonic field coupling becomes evident from the imaginary part of dielectric functions along x- and y-axes which is further supported by finite-difference time-domain (FDTD) simulations. Enormous near-field enhancement between Au-NPs leads to surface-enhanced Raman scattering (SERS)-based detection of an ultralow concentration (10 μM) of crystal violet dye. Further, FDTD simulation reveals that hotspot formation takes place between Au-NPs due to lesser interparticle gaps along the Au-NP arrays compared to the ones between two adjacent arrays. Thus, Au-NP arrays exhibit in-plane anisotropic optical response. The improved SERS-based detection efficacy of complex molecules is attributed to their enhanced Raman scattering cross-section in the vicinity of these hotspots. This study demonstrates that self-organized Au-NP arrays on nanoscale rippled-Si substrates can work as an efficient and longevous SERS sensor due to the prolonged stability of Au in environmental conditions. This study will pave the way to fabricate plasmonic devices and SERS-based sensing of complex molecules having low Raman scattering cross-sections.

Joint shear strength models for exterior RC beam-column connections exposed to biaxial and uniaxial cyclic loading

Joint shear strength models available in the literature can predict the shear strength for reinforced concrete (RC) beam-column connections exposed to uniaxial cyclic loading, while an accurate biaxial joint shear strength model is still lacking. Gene expression programming (GEP) is used in this research to develop uniaxial and biaxial joint shear strength models for exterior RC beam-to-column connections exposed to uniaxial and biaxial cyclic loading respectively. The GEP models are developed based on an experimental database available in the literature, where the models are randomly trained and tested. Uniaxial joint shear strength is also predicted using the ACI 352 and ASCE 41 formulations for connections exposed to uniaxial cyclic loading. The performance of the GEP models is statistically evaluated using the coefficient of determination R-squared. The R-squared values are 79%, 79%, 95% and 93% for the ACI, ASCE, uniaxial GEP and biaxial GEP models, respectively. The R-squared values of the GEP models are high, which confirms their accuracy and indicates that they are more fitting to the experimental results than the ACI and ASCE formulations.

Generalized ellipsometry characterization of Ag nanorod arrays prepared by oblique angle deposition

Silver nanorods arrays (AgNRs) prepared by oblique angle deposition were characterized by the generalized ellipsometry method in the spectral range from 370 to 950 nm. Three structure models were used to fit the ellipsometry data, the uniaxial model, the biaxial orthorhombic model, and the biaxial monoclinic model. Unlike the uniaxial model reported in most literature, the biaxial models are found to give better fitting results. The optical properties along the three principle axes are different: along long axis it displays predominantly metallic behavior; along one short axis it approaches to a lossless dielectric while along the other it behaves as an absorbance dielectric. The AgNRs also demonstrate epsilon-near-zero property with the real part of dielectric constant along the rod being very close to zero at wavelength of 416 nm, which is expected to be tuned with changing of the vapor incident angles.

Dependence of Light Curves on Phase Angle and Asteroid Shape

Abstract We investigate the phase angle dependence of asteroid light curves using numerical scattering models applied to simple body shapes. For simplicity, the Kaasalainen scattering parameters are obtained from the corresponding Hapke scattering laws for C-type, S-type, and V-type asteroids. The spectral types differ substantially in the role of multiple scattering (which is largely a function of their geometric albedos) but we find that the differences on the light curve versus phase relations are modest. Using a Kaasalainen scattering law, the amplitudes and axis ratios with respect to different phase angles from 0° to 140° are plotted for these types of asteroids based on a biaxial ellipsoid shape model. Additionally, we examine the relationship between amplitude and the axis ratio for a contact binary represented by identical biaxial ellipsoids, including the effects of shadowing of one component by the other. We compare the models with published high phase angle observations, and with interstellar object 1I/‘Oumuamua (Δm = 2.5 mag at a phase angle of α = 23°), finding an axis ratio of 5.2: 1 if represented as a single ellipsoid and 3.5: 1 for each component if represented as a nose-to-nose contact binary. While a detailed fit is not attempted, the comparison shows that the single ellipsoid model is better.

A refined numerical model for determining inflation-burst behavior of composite membrane structures

The airship structures made of multi-layer composite fabrics or membranes can offer the platform for earth observations, wireless communications and space research due to light weight and good mechanical performance. The structural safety and serviceability strongly depend on material properties and working conditions. Available studies are limited within service stress limits or are lack of suitable biaxial tensile constitutive models for understanding structural behavior. This paper thus focuses on a refined numerical model for determining inflation-burst behavior of composite airship structures considering new biaxial constitutive equations, novel failure criteria and manufacture factors.The differences between ideal and real forms of airship structures, e.g. volume difference, demonstrate the necessity for incorporating cutting-pattern effects in the initial numerical model. For structural analysis, stress distributions on real structural forms are different from those on ideal forms because of welding parts that can enhance local stiffness. The ultimate pressures are 56.7 kPa and 59.5 kPa for ideal and real structural forms. Structural breaking initiated at the maximum diameter of ideal structural forms propagates fast while welding parts can prevent breaking propagation for real structural forms. Therefore, the refined numerical model can reveal basic structural behavior and safety performance of airship structures in the inflation-burst processes.

漢字結構類型

Previously published analytical framework for the spatial configuration of Hanzi portrays Hanzi as having many complex spatial configurations, but fails to generate usefulness for the learning of Hanzi script, meaning or sound. Such framework has also been limited by being generated from only small sample size of simplified Chinese Hanzi. This paper present s a simple bi-axial analytical model, by which Hanzi’s spatial configuration can be dissected on the horizontal and vertical axis, into mono-partite or multipartite configurations on the horizo ntal axis, or single and multi-tiere configuration on the vertical axis. Each part can again be subdivided into tiers, and each tier into parts. The model is tested using Hanzi from standard and simplified Chinese Hanzi, Korean Hanja, Japanese Kanji, and Vietnamese chữ Nôm. The analysis shows that the model can be applied to all the script within the Hanzi region. The model is likely to generate useful insights as well as new approaches for the teaching of sound, script and meaning for Chinese Hanzi learning by improving the transpare ncy of Hanzi script, and pave the way to better script pronunciation transformation learning.

Large lattice mismatch induced perpendicular magnetic anisotropy and perpendicular exchange bias in CoPt/FeMn bilayer films

Perpendicular magnetic anisotropy and perpendicular exchange bias of CoPt/FeMn bilayers fabricated by dc magnetron sputtering were investigated in this work. Magnetic anisotropy, showing strong dependence on thickness of CoPt layer, changes from perpendicular magnetic anisotropy (PMA) into in-plane magnetic anisotropy when CoPt layer is thicker than 4.5 nm. The evolution of internal stress with thickness, from tensile to compressive, has been analyzed by sin2ψ method using an equal biaxial stress model. Distinctive perpendicular exchange bias (PEB) has been successfully established due to PMA of CoPt and out-of-plane spin component of 3Q-spin-structured FeMn. FeMn thickness dependence of exchange bias field has been systematically investigated.

Strain-optical behavior of polyethylene terephthalate film during uniaxial stretching investigated by Mueller matrix ellipsometry

Polyethylene terephthalate (PET) has gained widespread applications in various flexible devices where its optical properties after drawing process in manufacturing play a great importance in the performance of devices. In this work, the strain-optical behavior of pre-oriented polyethylene terephthalate (PET) film during uniaxial stretching is studied utilizing a proposed anisotropic model and Mueller matrix ellipsometry (MME). In the biaxial anisotropic model, the molecular chain orientation is correlated to the change of refractive indices and strain-induced birefringence, while the rotation of molecular chains is directly characterized by the rotation of principal optical axis. According to this model, the refractive indices, extinction coefficients and Euler angles extracted from measured Mueller matrix spectra can be used to interpret the micro-structural response of PET. A set of tensile tests have been carried out, with loading direction being varied. The results show that the strain-induced birefringence is linearly correlated to strain, while loading direction significantly affects the slope of achieved birefringence-strain curve. Meanwhile, the birefringence exhibits a positive linear relation with the orientation estimated by extinction coefficients. Through the analysis of the Euler angle ϕE, the principal optical axis rotating towards the tensile direction is accurately observed. Our results show that MME can provide a deep and systematic understanding of strain-optical behavior which can give accurate control of the optical properties of polymer films during deformation.

Multiaxial cyclic behaviour of extruded and forged AZ80 Mg alloy

The quasi-static and cyclic response of as-extruded and closed-die extruded-forged AZ80 Mg alloy forged at 250 °C and 20 mm/sec was investigated. Servo hydraulic, fully reversed, strain controlled uniaxial “push-pull”, pure torsion, and biaxial fatigue testing were also conducted on the closed-die forged alloy. Two uniaxial loading paths (pure axial and pure shear) and three different biaxial loading paths were investigated (proportional loading, and non-proportional loading at phase angles of 45° and 90°). After forging of the as-extruded billet, the yield stress in the axial direction increased by 46%, the failure elongation by 35% and the ultimate strength by 13%. The spatial variation in both the local texture, microstructure and superficial hardness throughout the cross section of the forging was investigated and discussed. The web region in the center of the forged billet exhibited a virtually fully recrystallized and refined microstructure with intense basal texture, whereas the rib regions on each side exhibited a partially recrystallized and coarser microstructure with less intense texture. The fatigue life of the forged material in the axial direction showed dramatic improvement relative to the as-extruded material at strain amplitudes which were less than 0.35%. However, at higher strain amplitudes, there are significantly higher cyclic stresses (and associated fatigue damage) in the forged material (relative to the as-extruded), resulting in a decrease in life under fully reversed strain controlled fatigue loading. For the pure axial strain path, the total amount of strain energy density (SED) observed in the stabilized response was a function of number of cycles only, and was insensitive to material condition (as-extruded or forged). However, for the forged material, of all the strain paths investigated, only the pure shear path demonstrated a significantly different relationship of total SED vs. life. Furthermore, the amount of total SED for a given number of cycles decreases when biaxial loading is introduced, though following the same general relationship as the pure axial strain path. The effect of a decrease in total SED for a given number of cycles occurred in all biaxial strain paths, with proportional being the least prominent, then 45° and 90° out of phase being progressively more pronounced respectively. Both the Smith Watson Topper (SWT) and Jahed-Varvani (JV) models were utilized to predict the fatigue life of the uniaxial and biaxial cyclic tests. Calibration of each models intrinsic parameters were done using both of the uniaxial loading paths individually, then these same parameters were used in combination with one another to predict the life in the biaxial cases. Both the SWT and JV models are capable of giving an acceptable prediction, however the JV model’s prediction is more reliable, especially when the cyclic response has pronounced asymmetry. The biaxial fatigue response is somewhat dominated by the axial component for two significant reasons; firstly, the shape of the hysteresis in the shear direction dramatically changes based on phase angle and axial strain amplitude, whereas the axial hysteresis loop remains somewhat invariant to the presence or modulation of the other loading axis. Secondly, the initial crack propagation mode is predominantly transverse to the axial direction in all strain paths except for pure shear (which exhibits longitudinal cracking). Tensile cracking dominating the biaxial failure mode provides qualitative justification of a modification factor to an existing energy based biaxial fatigue life prediction model, enabling it to predict the life of extruded and forged AZ80 Mg reliably for a variety of different biaxial strain paths.

Analysis on Evolution of Force Chain and Contact Network of Non-Cohesive Soil

A biaxial test model was established based on the discrete element method to simulate the microscopic evolution of non-viscous soil upon loading. The shear strain, deviator stress and volumetric strain of the samples at different time steps were recorded, the evolution process of the force chain in the samples was observed, and the average degree (coordination number), 3-cycle and average clustering coefficient over force-chain particles were also analyzed respectively from the perspective of complex network. The following analysis results are obtained. The larger the value of inter-particle friction coefficient, the higher the peak value of shear stress, and the more obvious the strain softening phenomenon. The force chains in the samples with higher inter-particle friction coefficient tend to be more vulnerable to damage during loading. In the loading process, the average degree first increases, then decreases and finally tends to be stable. The value of average degree increases with the increase of confining pressure, and decreases with the increase of friction coefficient. The clustering coefficient of the particles within the force-chain particles is linearly related to the average length of the force chains at critical state.

Research on fast self-learning improvement of ADRC control algorithm for film thickness control system

In the biaxially stretched film (BOPP) thickness control system, the traditional PID and Active-Disturbance Rejection Controller (ADRC) can’t achieve the ideal control effect. The Smith prediction method is used in the essay to establish a discretization model for the BOPP thickness control system. Combining with BP self-learning algorithm, a fast self-learning improved ADRC control algorithm (FSADRC) is proposed. By means of the additional momentum term and the adaptive learning rate method, the nonlinear combination of the ADRC system is adjusted in real time, the optimal control parameters are found, and the parameters are self-tuned. As a consequence, the improved algorithm is applied to the biaxial tensile film thickness control model. The simulation results show that the method has the advantages of high response speed and strong self-adaptive ability, which can effectively improve the control performance of the BOPP thickness control system.