Wenbin Yu

Purdue University | Purdue · School of Aeronautics and Astronautics

Traditional multiscale methods homogenize a beam-like structure into a material point in 1-D continuum with effective properties computed over a structure gene in terms of a cross-section or a 3D segment with spanwise periodicity. Such methods lose accuracy when dealing with real world beam-like structures usually not uniform or periodic along the...

A chiral mechanical metastructure is a structure consisting of periodically arranged, rationally designed asymmetric unit cells (UCs). Chiral metastructures can exhibit unprecedented smart properties for achiral metastructures, such as extension-twist couplings. The objective of this paper is to apply the mechanics of structure genome (MSG), a unif...

Traditional multiscale methods homogenize a beam-like structure into a material point in 1D continuum with effective properties computed over a structure gene (SG) in terms of a 2D cross-section or a 3D segment with spanwise periodicity. Such methods lose accuracy when dealing with real beam-like structures usually not uniform or periodic along the...

SwiftComp mobile App based on iOS and Android platforms has been developed to analyze composite materials using Google’s Flutter framework and dart language. It is a user-friendly App for computing properties for composites by utilizing SwiftComp capability. The App is currently available to download on iOS AppStore and Google Play Store. The curre...

Heterogeneous Solid Element (HSE) is developed based on Mechanics of Structure Genome (MSG) to model a heterogeneous body as an equivalent solid element by an effective element stiffness matrix. HSE modeling includes homogenization, macroscopic global analysis, and dehomogenization to recover local strain/stress fields. HSE avoids the local periodi...

Equivalent 3D properties are obtained for composite thin-walled 3D structures using the concept of mechanics of structure genome. The adopted homogenization technique interprets the unit cell associated with the thin-walled 3D structures as an assembly of plates, and the overall strain energy density of the unit cell as a summation of the plate str...

Over the past few years, a few experimental failure data of composites have been collected. It would be of interest to leverage the existing data to improve the prediction of failure criteria. In this paper, we developed a framework that combines sparse regression with compressed sensing to discover failure criteria of composites from experimental...

This paper presents a finite element (FE) coupled positive definite deep neural networks mechanics system (FE-PDNN). The proposed approach enables neural networks to learn the constitutive law based on the structural level response, such as force and displacement, and solves the convergence robustness issue of learning the constitutive law of a sev...

Finite element simulation of the column bending test (CBT) is carried out using shell elements with anisotropic viscoelastic section properties. The CBT is an experimental method for evaluating the bending behavior of thin-ply high strain composites (TP-HSC), to support development of deployable composite booms for space structures. A linear viscoe...

View Video Presentation: https://doi.org/10.2514/6.2022-1120.vid The objective of this paper is to develop a nonlinear viscoelastic–viscoplastic constitutive model for epoxy polymers. The classic nonlinear viscoelasticity model is reformulated to yield a closed-form incremental constitutive relation, which relates the stress increments to the visco...

View Video Presentation: https://doi.org/10.2514/6.2022-1119.vid In this paper, a mechanics of structure genome (MSG)-based nonlinear shell theory is introduced. The theory uses an implicit algorithm combining the Euler’s and Newton’s method that can be applied for shell modeling as well as 3D homogenization. This theory has been implemented into t...

View Video Presentation: https://doi.org/10.2514/6.2022-2454.vid Structural design optimization of composite helicopter rotor blades through numerical analysis is a challenging task. Among many studies in the past, strength properties and failure conditions of composite structures are generally neglected. With advanced composite analysis tools, man...

Traditional multiscale methods homogenize a beam-like structure into the Timoshenko model or the Euler-Bernoulli model with effective properties computed over a structure gene in terms of a cross-section or a 3D segment with spanwise periodicity. However, for real beam-like structures such as wind turbine blades, helicopter rotor blades and flexbea...

Sandwich structures are important structural members in modern lightweight engineering. Accurate and effective buckling predictions are vital to the design and optimization of sandwich structures. This paper extends and validates a homogenization theory namely the mechanics of structure genome (MSG) in predicting eigenvalue buckling of sandwich str...

An efficient shell model based on mechanics of structure genome (MSG) is introduced to predict the manufacturing induced residual stress and deformation for composite laminates. This model utilizes shell elements in commercial finite element software to represent the composite laminate, which greatly reduces the computational cost compared with a d...

A data-driven multiscale modeling approach is developed to predict the effective thermal conductivity of two-dimensional (2D) woven composites. First, a two-step homogenization approach based on mechanics of structure genome (MSG) is developed to predict effective thermal conductivity. The accuracy and efficiency of the MSG model are compared with...

Machine learning models are increasingly used in many engineering fields thanks to the widespread digital data, growing computing power, and advanced algorithms. The most popular machine learning model in recent years is artificial neural networks (ANN). Although many ANN models are used in the constitutive modeling of composite materials, there ar...

A reliable design of a composite structure needs to consider the failure of the composites. Hashin failure criterion is one of the most popular phenomenological models in engineering practice due to its simplicity of application. Although remarkable success has been achieved from the Hashin failure criterion, it does not always fit the experimental...

A data-driven multiscale modeling approach is developed to predict the effective thermal conductivity of two-dimensional (2D) woven composites. First, a two-step homogenization approach based on mechanics of structure genome (MSG) is developed to predict effective thermal conductivity. The accuracy and efficiency of the MSG model are compared with...

The commercial finite element (FE) code Abaqus is coupled with the deep neural network (DNN) model, namely Abaqus-DNN mechanics system, to learn the constitutive law of the fiber-reinforced composite. The proposed system enables data communication between Abaqus and DNN model, which leverages the versatile FE analysis ability of Abaqus and the powe...

Composite structures are increasingly analyzed in a multiscale way, where lower scale structures are homogenized and effective properties such as structural stiffness are passed to upper scales. However, strength properties are rarely treated this way to construct a complete failure envelope for the structural element. In this work, we propose to u...

Machine learning models are increasingly used in many engineering fields thanks to the widespread digital data, growing computing power, and advanced algorithms. Artificial neural networks (ANN) is the most popular machine learning model in recent years. Although many ANN models have been used in the design and analysis of composite materials and s...

An Abaqus coupled positive definite deep neural network (Abaqus-PDNN) mechanics system was presented. The proposed approach applies positive definite constraint to the output of DNN, which solves the convergence robustness issue of learning the constitutive law of a severely damaged material. In addition, the lamination theory is introduced to the...

The objective of this paper is to develop a constitutive model for finitely deformed viscoelastic-viscoplastic materials and a micromechanics approach to homogenizing composites consisting of such materials. The development of the constitutive model involves establishing a thermodynamic framework based on finite strain theory, developing a viscoela...

In this paper, a multiscale simulation method for analyzing deployable composite structures is presented. Effective shell properties of the composites are obtained based on mechanics of structure genome (MSG) homogenization, and then implemented into a user-subroutine UGENS for structural simulation with shell elements in Abaqus. The column bending...

Thin-ply high strain composite (TP-HSC) technology is being increasingly adopted for high-performance aerospace applications. Albeit many of these structures such as deployed booms can be modeled as one-dimensional beams, there is a lack of themoviscoelastic beam models to efficiently and accurately simulate TP-HSC. This work uses mechanics of stru...

Equivalent plate properties are obtained for composite corrugated structures using mechanics of structure genome. The method developed in this paper interprets the unit cell associated with the corrugated structure as an assembly of plates, and the overall strain energy density of the unit cell as a summation of the plate strain energies of these i...

Machine learning models are increasingly used in many engineering fields thanks to the widespread digital data, growing computing power, and advanced algorithms. Artificial neural networks (ANN) is the most popular machine learning model in recent years. Although many ANN models have been used in the design and analysis of composite materials and s...

The effective properties of composites are influenced by the time-dependent behavior of polymer matrices, which are very sensitive to changes in temperature. Improved plate and beam models are required to efficiently design, and simulate composite structures when the long-term performance of large anisotropic composite structures is the matter of i...

Quick and accurate predictions of cross-sectional properties are required in the preliminary design of thin-walled composite beams. Existing literature provides accurate analytical solutions to the problem, albeit limited to open and single cell sections with stress continuity constraints imposed. Mechanics of structure genome has been used to deve...

A neural network enhanced system containing a subsystem with one or multiple neural networks is proposed. Instead of defining the loss function as the direct output of a neural network model, the proposed method uses the system output, which can be measured from experiments, to define the loss function. The loss function is contributed by the outpu...

Artificial neural network (ANN) models are used to learn the nonlinear constitutive laws based on indirectly measurable data. The real input and output of the ANN model are derived from indirect data using a mechanical system, which is composed of several subsystems including the ANN model. As the ANN model is coupled with other subsystems, the inp...

The objective of this paper is to develop the implicit integration scheme and calibration method for a recently developed cohesive zone model (CZM), for improved predictive capabilities in interlaminar delamination. The concept of string-based CZM is briefly introduced. An associated implicit integration scheme, which can handle complex separation...

Unstable buckling leads to the failure of thin-walled cylinders under axial compression. Because of the manufacturing and loading imperfections, a significant variation was observed between experimental and theoretical buckling load. The current design criteria use a knockdown factor to estimate the buckling load of thin-walled structures. However,...

The objective of this paper is to develop an anisotropic continuum damage model for high-cycle fatigue. A viscodamage model, which can handle frequently observed brittle damage phenomena, is developed to produce stress-dependent fatigue damage evolution. The governing equation for damage evolution is derived using an incremental method. A closed-fo...

Structural integrity, durability, and thermal stability represent critical areas for adequately modeling the behavior of composite materials. Polymeric matrices are prone to have time-dependent behavior very sensitive to changes in temperature that influence the effective properties of the composite. This study extends mechanics of structure genome...

Stiffened panels buckle under compressive loads which would degrade load-bearing capabilities of the structures. Fast yet accurate estimations of buckling loads and associated mode shapes are critical in the early stages of design and optimization. This paper presents a method based on the mechanics of structure genome (MSG) for the global buckling...

In the finite element analysis (FEA) of composite structures, shell and beam elements with homogenized material properties are often used to reduce the computational costs and modeling efforts. However, significant loss of accuracy may occur due to constitutive modeling limitations of commercially available software packages for complex mesostructu...

A new failure criterion for fiber tows (i.e. yarns) is developed based on a micromechanical model using the mechanics of structure genome (MSG) and a deep learning neural network model. The proposed failure criterion can be applied to yarns in mesoscale textile composites modeling while capturing the failure initiation at the fiber and matrix level...

Mechanics of structure genome (MSG) has been extended to provide a unified approach to predict the thermoelastic behaviors of composite structures. The variational statement of the MSG models has been modified to capture pointwise temperature distribution in composite structures. The effective coefficients of thermal expansions (CTEs) are predicted...

Mechanics of structure genome (MSG) is a unified homogenization theory that provides constitutive modeling of three-dimensional (3D) continua, beams and plates. In present work, the author extends the MSG to study the buckling of structures such as stiffened and sandwich panels. Such structures are usually slender or flat and easily buckle under co...

This is the user manual for ANSYS Workbench SwiftComp GUI: An ANSYS Workbench Extension for Multiscale Modeling.

The structure of Printed Circuit board (PCB) is very complicated because it consists of woven composites and custom defined conducting layers. To improve the reliability of PCB, it is critical to predict the constitutive relations accurately. This study by implementing Mechanics of Structure Genome (MSG), homogenizes a multilayer PCB to determine t...

Predicting the effective electromechanical properties for piezoelectric fiber composite patches is crucial for analysis of smart structures equipped with such patches. In particular, analytical homogenization models are attractive but are limited by the complexity of the microstructure and the multiphysics involved. The macro-fiber composite (MFC)...

This paper presents a simplified formulation of the mechanics of a structure genome (MSG). The MSG is a unified theory for multiscale constitutive modeling for all types of composite structures. It is generalized from the previous research works based on the variational asymptotic method (VAM), including the variational asymptotic beam sectional an...

The objective of this paper is to develop a micromechanics approach to the homogenization and macroscopic stability analysis of finitely deformed heterogeneous elastomers. An Euler–Newton predictor–corrector method is developed for homogenization. It consists of an Euler predictor and a Newton corrector step. Each step involves formulating a variat...

The objective of this paper is to develop a continuum damage model for fatigue prediction. A viscodamage model, which can rigorously handle damage anisotropy, distinct tensile and compressive damage behavior, and damage deactivation, is developed to produce stress-dependent fatigue damage evolution. An affine formulation governing damage evolution,...

Mechanics of Structure Genome (MSG) is extended to provide a new two-step homogenization approach to predict the viscoelastic behaviors of textile composites. The first homogenization step (micro-homogenization) deals with determining the viscoelastic properties of yarns from fibers (assumed to be linear elastic) and matrix (assumed to be linear vi...

The mechanics of structure genome has been extended to heat conduction problem of composite materials with a general linear thermal imperfect interface model. This full field micromechanics approach is applied to predict the effective thermal conductivity of composite materials containing thermal imperfect contact between the matrix and the reinfor...

Based on the recently discovered mechanics of structure genome, a micromechanics theory is developed for computing the effective properties and local fields of aperiodic heterogeneous materials. This theory starts with expressing the displacements of the heterogeneous material in terms of those of the corresponding homogeneous material and fluctuat...

Mechanics of structure genome (MSG) is used to develop an approach for multiscale structural analysis of textile structures. First, MSG is used to predict the properties of yarns having realistic geometry. Then, beam and plate stiffness matrices are predicted based on the yarn and matrix properties using MSG. These beam and plate stiffness matrices...

Accurate predictions of physically nonlinear elastic behaviors of a material point in the structure are essential to the further analyses which are beyond the linear elasticity regime, for example, the progressive damage and the failure. In light of substantial experimental evidence of nonlinear shear stress-strain responses in composites, it is ne...

The objective of this paper is to critically evaluate the accuracy and efficiency of a general-purpose micromechanics approach based on the Mechanics of Structure Genome (MSG), when it is applied to the constitutive modeling of 3D structures. The Generalized Method of Cell (GMC) is chosen as a reference method during efficiency evaluation. The pred...

A new multiscale modeling approach based on mechanics of structure genome (MSG) has been proposed to analyze honeycomb sandwich structures. On the one hand, MSG can be used to homogenize a honeycomb core as a homogeneous solid to get effective elastic properties without various boundary conditions (BCs). The results are compared with those obtained...

A convenient and robust way to convert an ordinary structure into a smart one is to adhere a piezoelectric macro-fiber composite (MFC) patch to it. Although the commercialization of the MFC has facilitated numerous sensor and actuator applications, analysis of host structures has mainly relied on homogenized constants that were obtained with variou...

This paper presents a hybrid rule of mixtures for calculating the complete set of effective three-dimensional thermoelastic properties of a composite laminate when it is approximated as an equivalent, homogeneous, anisotropic solid. The laminate can be made of generally anisotropic layers with arbitrary layup sequence. This hybrid rule of mixtures...

The objective of this paper is to develop a nonlocal continuum damage model for brittle fracture. A nonlocal damage conjugate force tensor is obtained from the “local” one, using an integral-type regularization technique, and the thermodynamic equations are formulated in a nonlcally generalized standard manner. A nonlocal damage model is developed...

Damaging constitutive models are incorporated into the variational asymptotic beam sectional analysis method (VABS). Under the governing of the virtual work principle, Newton’s method is applied to solve for the finite cross-sectional warping field and the damage variables according to continuum damage mechanics models from the literature. These so...

A novel approach for the micromechanical analysis of periodically heterogeneous composite materials is proposed in this paper. It is based on the use of refined beam theories for the modeling of the microstructure and the mechanics of structure genome (MSG) for the derivation of the governing equations of the unit cell problem. On the one hand, MSG...

The interlaminar stress in angle-ply and cross-ply composite laminates subjected to twisting deformation are investigated. Two mechanisms of interlaminar load transfer have been developed by studying the angle-ply laminate and the cross-ply laminate subjected to uniform axial extension, thermoelastic deformation and anticlastic bending deformation....

Mechanics of Structure Genome is extended to provide a novel two-step homogenization approach to predicting the effective properties of textile composites. The first homogenization step (micro-homogenization) deals with determining the effective properties of tows (yarns) from fiber and matrix properties. In the second homogenization step (macro-ho...

Composite beams could have complex cross-sections composed of many layers with different materials and layup angles. The anisotropic and heterogeneous features render three-dimensional (3D) finite element analysis (FEA) with layer details computationally expensive. Smeared properties approaches are commonly used in analyzing such structures. Mechan...

The objective of this paper is to develop a string-based cohesive zone model (CZM) for interlaminar delamination, whose associated cohesive elements behave reliably and consistently when deformed along complex separation paths and can display experimental critical energy release rate–mode mixture ratio relationships. Each cohesive element is ideali...

This paper presents a geometrically nonlinear analysis of composite beams including static, dynamic, and eigenvalue analyses. With the increase in size and flexibility of engineering components such as wind turbine blades, geometric nonlinearity plays an increasingly significant role in structural analysis. The Geometric Exact Beam Theory (GEBT), p...

Because of composite materials’ inherent heterogeneity, the field of micromechanics provides essential tools for understanding and analyzing composite materials and structures. Micromechanics serves two purposes: homogenization or prediction of effective properties and dehomogenization or recovery of local fields in the original heterogeneous micro...