ABAQUS Scripting Interface Research Articles

A comprehensive investigation on the effect of controlling parameters of ultrasonic peening treatment on residual stress and surface roughness: Experiments, numerical simulations and optimization

This paper aims to study the effect of controlling parameters of ultrasonic peening treatment (UPT), including the pin diameter, the vertical velocity of the pin, friction coefficient etc. on the residual stress, PEEQ and surface roughness. A method was promoted to simulate the UPT process using the ability of the ABAQUS scripting interface and transferring results between ABAQUS analyses. The finite element results of the proposed method were consistent with the UPT simulation. Moreover, the finite element results agreed well with experimental measurements of residual stress, surface roughness and surface deformation. The results revealed that increasing the pin diameter, the vertical velocity of the pin and also the number of impingements increased the depth of the compressive residual stress layer. Decreasing the vertical and horizontal velocity of the pin and increasing the pin diameter and the distance between two adjacent impingements resulted in a decline of surface roughness parameters (Ra and Rq). A combination of finite element model and multi-objective optimization technique was implemented to determine the optimum controlling parameters of UPT for reaching the maximum compressive residual stress and the minimum surface roughness. For the optimum proposed controlling UPT parameters, the values of −386 MPa, 16.7 μm and 20.9 μm were obtained for the surface residual stress, Ra and Rq, respectively.

A deep learning-based method for hull stiffened plate crack detection

Deep learning has attracted the attention of many researchers for structural health monitoring. However, it is difficult to use most of the deep learning-based techniques to detect damage throughout the life cycle of a large or inaccessible structure, especially a ship. Few studies have focused on hull stiffened plate crack damage detection. We propose such a method based on deep learning using a convolutional neural network (CNN). The model is trained on acceleration data, which are calculated by the Abaqus scripting interface. Five crack locations and four crack lengths are considered, as well as the intact condition. The effects of damping ratio, loading area, and load level on the proposed method are considered. The robustness of the proposed approach to noise and stiffener slenderness ratio are also discussed. The proposed method is compared to the multilayer perceptron method by wavelet packet transformation using the same data, so as to quantify its performance. The results show that the proposed method performs better at single- and double-crack detection, and is less sensitive to noise, damping ratio, loading area, and load level.

The influence of fiber bundle width on the mechanical properties of filament-wound cylindrical structures

The fiber bundles crossovers, undulations and overlaps are inherent in the helical winding method of filament-would cylindrical structures such as composite tubes and pressure vessels. As a result, material properties will be highly affected because of the presence of these inherent defects in a structure. This research aims to evaluate the effect of these undulation regions on the local material properties and global mechanical performance of the tubes. In this article, a three-dimensional repeated unit cell (RUC) in a meso‑scale is developed to investigate the mechanical and thermal properties of the filament-wound composite tubes with different fiber bundle width. In this regard, three models of classical lamination theory (CLT), mosaic and fiber undulation were used and compared with each other. The given RUC is subjected to periodic boundary conditions (PBCs), and its mechanical and thermal behavior is studied by asymptotic homogenization theory (AHT). All the modeling steps are performed by an ABAQUS scripting interface (ASI) in the Python programming language. As an applied example, the effective material constants of a glass/epoxy tube with [ ± 45] lay-up are determined and the effects of different winding patterns are discussed. The results show that the fiber undulation model can cause up to 15.7% change in the mechanical and thermal properties of interweaved layers compared to the CLT. Moreover, the stress/strain distribution in a composite tube subjected to internal pressure is obtained. The findings of this article confirm that the global mechanical performance of cylindrical structures could be remarkably influenced by the local variations of the mechanical properties due to the fiber bundles crossovers/undulations/overlaps.

A 3D RVE model with periodic boundary conditions to estimate mechanical properties of composites

Micromechanics is a technique for the analysis of composites or heterogeneous materials which focuses on the components of the intended structure. Each one of the components can exhibit isotropic behavior, but the microstructure characteristics of the heterogeneous material result in the anisotropic behavior of the structure. In this research, the general mechanical properties of a 3D anisotropic and heterogeneous Representative Volume Element (RVE), have been determined by applying periodic boundary conditions (PBCs), using the Asymptotic Homogenization Theory (AHT) and strain energy. In order to use the homogenization theory and apply the periodic boundary conditions, the ABAQUS scripting interface (ASI) has been used along with the Python programming language. The results have been compared with those of the Homogeneous Boundary Conditions method, which leads to an overestimation of the effective mechanical properties. According to the results, applying homogenous boundary conditions results in a 33% and 13% increase in the shear moduli G23 and G12, respectively. In polymeric composites, the fibers have linear and brittle behavior, while the resin exhibits a non-linear behavior. Therefore, the nonlinear effects of resin on the mechanical properties of the composite material is studied using a user-defined subroutine in Fortran (USDFLD). The non-linear shear stress-strain behavior of unidirectional composite laminates has been obtained. Results indicate that at arbitrary constant stress as 80 MPa in-plane shear modulus, G12, experienced a 47%, 41% and 31% reduction at the fiber volume fraction of 30%, 50% and 70%, compared to the linear assumption. The results of this study are in good agreement with the analytical and experimental results available in the literature

Numerical Simulation and Experimental Studies on Elastic-Plastic Fatigue Crack Growth

A elastic-plastic fatigue crack growth (FCG) finite element model was developed for predicting crack growth rate under cyclic load. The propagation criterion for this model was established based on plastically dissipated energy. The crack growth simulation under cyclic computation was implemented through the ABAQUS scripting interface. The predictions of this model are in good agreement with the results of crack propagation experiment of compact tension specimen made of 304 stainless steel. Based on the proposed model, the single peak overload retardation effect of elastic-plastic fatigue crack was analyzed. The results shows that the single peak overload will reduce the accumulation rate of plastic energy dissipation of elements at crack tip plastic zone, so that crack growth will be arrested. The crack growth rate will not recover until the crack tip exceed the affected region. Meanwhile, the crack growth rate is mainly determined by the amplitude rather than the mean load under the condition of small scale yielding. The proposed model would be helpful for predicting the growth rate of mode I elastic-plastic fatigue crack.

Fatigue evaluation of grouted connections under bending moment in offshore wind turbines based on ABAQUS scripting interface

The fatigue behavior evaluation under bending moment is extremely important to the grouted connection in monopile offshore wind turbines. Based on the scripting interface of ABAQUS software, finite element model of the grouted connections was established automatically in accordance with the user defined parameters by Python language. Based on the experimental material test of grout material, the grout material was simulated by using three-dimensional concrete damaged plasticity (CDP) model in ABAQUS. Full model and half model were compared under fatigue limit state (FLS), and numerical results are presented in terms of hot spot stress in steel and third principle stress in grout material. It was found that half model could decrease calculation time significantly with more conservative evaluation result. Furthermore, parametric studies were conducted based on the half models about two different shear keys’ arrangements as well as the height and distance of shear keys. And it is found that there are slight differences for two models in calculated design life when the interface behavior between steel and grout material is modeled by Coulomb friction law.

Helical spring design optimization for endoscopic devices using a design-of-experiments approach

Event Abstract Back to Event Helical spring design optimization for endoscopic devices using a design-of-experiments approach Hamid Ebrahimi1, 2, Albert Yee1, 2, 3 and Cari Whyne1, 2, 3 1 Sunnybrook Research Institute, Holland Musculoskeletal Program, Canada 2 University of Toronto, Institute of Biomaterials and Biomedical Engineering, Canada 3 University of Toronto, Department of Surgery, Canada Introduction: Endoscopes are long thin tubular devices for non-invasive visualization of the interior of cavities, canals and vessels. They can be inserted through natural orifices or small surgical incisions. A typical endoscope outer diameter is 10mm and length can vary from 70 to 180mm[1]. While some rigid endoscopes are used, the flexibility of articulated endoscopes is important in many clinical applications. Articulated endoscopes are generally controlled by cables and levers which bend the distal extremity of the device to enable route selection or to change the field of view. Challenges of flexible endoscopes include reliable advancement and steerability of the device tip[2]. Reliable advancement can be addressed by utilization of relatively rigid helical springs within the device shaft. However, steerability requires that the tip must be flexible to accommodate different bend radii. The aim of this study is to understand the main effects (geometric and physical properties of the tip and their interactions) that impact the radius of curvature governing steerability in traditional endoscopes. Methods: Using the Abaqus Scripting Interface (ASI), a helical coil and cable assembly were modeled with the cable connected to the coil proximal circumference (Figure 1). The cable was placed inside the helical spring to represent a common endoscope design configuration. A two-level factorial design-of-experiments methodology was utilized to understand the main geometric and physical effects and their interactions on the attainable radius of curvature (outcome). The effects of five coil parameters were assessed: pitch, height, Young’s modulus (E), applied force, and wire width. Abaqus dynamic/explicit was utilized to analyse 32 models generated using ASI. The results were analyzed using a commercial design-of-experiments-specific statistical package (Design-Ease). Based on the Box-Cox plot, a Log transformation of the output response was used to stabilize the variance. A Sum-of-Squares chart with a 2% weighted contribution threshold was utilized to determine the model inclusion criteria. Analysis of variance (with a Bonferroni correction) was used to determine the significance of the model, effects, and interactions. Results: The model, four of the input parameters (height, E, force, and wire width) and two interactions (between pitch/wire width and pitch/height/E/wire width) were found to be statistically significant (P<0.0001). The largest contribution to the model was wire width (effect=1.39, 58.33% contribution). The force and pitch/wire width interaction each had a negative influence, reducing the radius of curvature (allowing for tighter bends), whereas the height, E, wire width and pitch/height/E/wire width interaction showed a positive influence. Pitch and all other interaction effects below the 2% contribution threshold were applied as model error. Using this model, geometric and physical properties can be optimized to meet specific endoscopic tip design criteria. A small pitch and wire width yield a radius of curvature optimal for acute bending radii, however, if due to design restrictions, a larger wire width is necessary, an increase in pitch may accommodate to yield a sufficiently small bending radius. Conclusion: A robust computational model was developed using a design-of-experiments approach that allows parametric optimization of endoscopic tip design parameters for radius of curvature minimization. Canadian Institutes of Health Research (CIHR)

A simple and compact Python code for complex 3D topology optimization

This paper presents a 100-line Python code for general 3D topology optimization. The code adopts the Abaqus Scripting Interface that provides convenient access to advanced finite element analysis (FEA). It is developed for the compliance minimization with a volume constraint using the Bi-directional Evolutionary Structural Optimization (BESO) method. The source code is composed of a main program controlling the iterative procedure and five independent functions realizing input model preparation, FEA, mesh-independent filter and BESO algorithm. The code reads the initial design from a model database (.cae file) that can be of arbitrary 3D geometries generated in Abaqus/CAE or converted from various widely used CAD modelling packages. This well-structured code can be conveniently extended to various other topology optimization problems. As examples of easy modifications to the code, extensions to multiple load cases and nonlinearities are presented. This code is useful for researchers in the topology optimization field and for practicing engineers seeking automated conceptual design tools. With further extensions, the code could solve sophisticated 3D conceptual design problems in structural engineering, mechanical engineering and architecture practice. The complete code is given in the appendix section and can also be downloaded from the website: www.rmit.edu.au/research/cism/.

Two-Dimensional Crack Growth Simulation under Mixed-Mode Loading

In this paper, an efficient simulation program (FCG-System) is proposed to simulate 2D fatigue crack growth under mixed-mode loading conditions. The simulation is basically an incremental crack extension procedure. An object-oriented modeling frame is proposed for simulating fatigue crack growth of complex structures. The modeling frame is developed in the context of the commercial FE code ABAQUS, utilizing Python language and ABAQUS Scripting Interface (ASI). The highly automatic finite element simulation method is not only used for a single crack tip, but also has been extended to the system of interactive multiple cracks. The robustness and the accuracy of the new simulation code will be shown by two examples, including single crack growth and multiple cracks growth. Those applications indicate that the implementation of the FCG-System, as proposed herein, can be a useful tool for this class of fatigue crack growth.

Analysis of effect of fiber orientation on Young’s modulus for unidirectional fiber reinforced composites

Young’s modulus of unidirectional glass fiber reinforced polymer (GFRP) composites for wind energy applications were studied using analytical, numerical and experimental methods. In order to explore the effect of fiber orientation angle on the Young’s modulus of composites, from the basic theory of elastic mechanics, a procedure which can be applied to evaluate the elastic stiffness matrix of GFRP composite as an analytical function of fiber orientation angle (from 0° to 90°), was developed. At the same time, different finite element models with inclined glass fiber were developed via the ABAQUS Scripting Interface. Results indicate that Young’s modulus of the composites strongly depends on the fiber orientation angles. A U-shaped dependency of the Young’s modulus of composites on the inclined angle of fiber is found, which agree well with the experimental results. The shear modulus is found to have significant effect on the composites’ Young’s modulus, too. The effect of volume content of glass fiber on the Young’s modulus of composites was investigated. Results indicate the relation between them is nearly linear. The results of the investigation are expected to provide some design guideline for the microstructural optimization of the glass fiber reinforced composites.

Modeling of nano-reinforced polymer composites: Microstructure effect on Young’s modulus

A computational numerical-analytical model of nano-reinforced polymer composites is developed taking into account the interface and particle clustering effects. The model was employed to analyze the interrelationships between microstructures and mechanical properties of nanocomposites. An improved effective interface model which is based on Mori–Tanaka approach and includes the nanoparticle geometry and clustering effects was developed. A program code for the automatic generation of two-dimensional multiparticle unit cell models of nanocomposites and finite element meshes on the basis of “grid method” algorithm was developed in the ABAQUS Scripting Interface. In the computational studies, it was observed that the elastic modulus increases with the increasing the aspect ratio of nanoparticles. The thickness and properties of effective interface layers and the shape and degree of particles clustering have strong influence on the mechanical properties of nanocomposite.

Numerical Simulation of Sliding Wear for Self-lubricating Spherical Plain Bearings

Based on the thermo-mechanical finite element analysis method, a thermal wear simulation program was designed for the wear properties analysis of spherical plain bearing with self-lubricating fabric liners. In the program, the classical Archard wear model was applied to analyze the dynamical wear process of the bearing, and Abaqus scripting interface was used to simulate the progressive accumulation of wear between contact surfaces. The position of maximum wear depth occurs at the central contact region and this is in close agreement with test results. The relative error of the maximum wear depth between the FEA prediction and experimental results is a little more than 10%. It is shown that the complex nonlinear wear process can be simulated with a series of discrete quasi static models and the wear simulation program could be used to analyze the practical mechanical and tribological properties of the spherical plain bearings.

Numerical Investigations of Young’s Modulus for Composites with Inclined Glass Fiber for Wind Energy Application

Young’s Modulus of glass fiber reinforced composites for wind energy applications are studied using numerical method. The effect of volume content of glass fiber on the Young’s modulus of composites is investigated. Results indicate the relation between them is nearly linear. In order to explore the effect of inclined angle of fiber on the Young’s modulus of composites, different finite element models with inclined glass fiber are developed via the ABAQUS Scripting Interface. Results indicate that Young’s modulus of the composites strongly depends on the inclined angle of fiber. A U-shaped dependency of the Young’s modulus of composites on the inclined angle of fiber is found, which agree with the experimental results. The results of the investigation are expected to provide some design guideline for the microstructural optimization of the glass fiber reinforced composites.

Automation of Design and Analysis in Simulation System for Rough Rolling Process of H-Beam

In view of present problems that interior information of H-beam in multi-pass hot rolling process is not clear enough, an integrated simulation system with automatic design and analysis is developed based on ABAQUS Scripting Interface. Architecture of simulation system is designed according to the process of rough rolling, and several key problems are illustrated in the paper. The reliability of the system is verified through the forming simulation of H-beam H250x125. The system is very helpful for experienced mill designers who are unfamiliar with finite element analysis to test new section designs through virtual hot rolling trials.

Determination of the loading path for tube hydroforming process of a copper joint using a fuzzy controller

Tube hydroforming of thin-walled parts ratio of the thickness to the diameter is too low and mainly depends on the process control parameters (the internal pressure and the axial feeding). These parameters determine the occurrence of forming limits, such as wrinkling and bursting. Trial-and-error method is not a convenient method to find loading path since it is costly. Convectional loading paths, which may easily result in a product with defects, cannot be used in this case. In this study, the loading path for hydroforming process of copper joint is determined using a fuzzy controller. The final goal is to obtain a calibrated product without any wrinkling or tearing. It is shown that the wrinkling, except severe wrinkling, is a repairable defect, while bursting is an irreparable defect. Simulation of the process is done by using finite element method in combination with a designed fuzzy controller. The Abaqus scripting interface is used for modeling the part and communicating with the Abaqus kernel. The explicit method is utilized to overcome convergence problems encountered in the implicit method.