Dr. Vijay Kumar
Dr. Vijay Kumar
Country: India
Education
Indian Institute of Technology (IIT): Bachelor’s in Mechanical Engineering
University of California, Berkeley: Master’s in Mechanical Engineering
Massachusetts Institute of Technology (MIT): Ph.D. in Mechanical Engineering
Company History
Aerospace Engineering Pvt. Ltd.: Research Scientist (5 years)
Indian Institute of Science (IISc): Professor (Present)
Expertise
Dr. Kumar is a leading expert in the field of composite materials and failure analysis using ABAQUS. He has extensive experience in modeling and simulating the mechanical behavior of composite structures under various loading conditions. Dr. Kumar’s research focuses on developing novel composite materials with improved strength, stiffness, and damage tolerance. He is also actively involved in developing new methodologies for failure analysis of composite structures using ABAQUS.
Composite Pressure Vessel simulation in ABAQUS
Pressure vessels are made using different methods today, and one of them is filament winding. This package shows the simulation of composite pressure vessels made using the filament winding method.
In this training package, three winding methods, planar, geodesic, and isotensoid, have been taught for filament winding pressure vessels. In this tutorial, two general methods also have been presented for simulating filament wound pressure vessels. One uses the Abaqus graphical user interface(GUI), and the other uses the Python script. On the other hand, two criteria, Tsai-Hill and Puck, have been used to model damage in the composite. A UMAT subroutine has been used to use the Puck criterion.
Composite pressure vessel analysis with Semi-Geodesic winding
Nowadays, pressure vessels are produced using various methods, one of which is filament winding. This package teaches the simulation of composite pressure vessels produced using the filament winding method. Filament winding itself has different methods, and one of the most widely used winding methods for producing composite vessels is the semi-geodesic filament winding method. In this package, first, the semi-geodesic method is described. Then, the simulation of a semi-geodesic vessel is performed using a Python script. Additionally, a UMAT subroutine is used to simulate the failure of composite materials used in the vessel.
Full Composite fatigue Add-on (Academic and industrial usage)
This package is designed to instruct users on how to utilize the composite fatigue modeling Add-on, which removes the need to write a subroutine for composite fatigue modeling. Instead, users can select the composite type, input material properties, and generate the subroutine by clicking a button. The Add-on includes four types of composites, and the generated subroutine for all types is the UMAT. These four types are Unidirectional, Woven, short fiber composites (chopped), and wood. The fatigue criteria used for each type are the same as its respective package. For example, the fatigue criteria for woven composites are identical to that used in the "Simulation of woven composite fatigue in Abaqus" package. This Add-on provides a simple graphical user interface for composite fatigue modeling, which can be utilized for both academic and industrial applications.
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Full Composite damage Add-on (Academic and industrial usage)
This package will teach you how to use the composite damage modeling Add-on. The Add-on eliminates the need for writing a subroutine for composite damage modeling. Instead, you only need to select the desired composite type, input the material properties, and click a button. The Add-on will then generate the subroutine for you. The Add-on includes four types of composites: Unidirectional, Woven, short fiber composites (chopped), and wood. The generated subroutine for all types is the VUSDFLD. The damage criteria used in each type is the same as the one used in its respective package. For instance, the damage criteria for the woven composite is identical to the one used in the "Simulation of woven composite damage in the Abaqus" package. This Add-on offers a user-friendly graphical user interface for composite damage modeling, which can be used for academic and industrial purposes.
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Composite Fatigue Simulation with VUMAT Subroutine in ABAQUS
This training package consists of four chapters that help engineers and researchers in the industry to understand the fundamental concepts and necessary tools for simulating composite fatigue using VUMAT subroutine in ABAQUS. The first chapter provides an overview of the fatigue behavior of composite materials, including the factors contributing to fatigue failure. The second chapter explores the failure mechanisms of composite materials and the types of damage that can occur. The third chapter discusses the effects of fatigue on composite materials, including how it affects the material's properties and performance. Finally, the fourth chapter focuses on using the VUMAT subroutine in ABAQUS for composite fatigue analysis, including the material models and criteria used to simulate the behavior of composite materials under various loading conditions. By mastering the concepts and tools presented in this package, engineers can develop more durable and reliable composite structures that can withstand cyclic loading over extended periods of time.
Composite simulation for experts-Part-3
Pay attention to the syllabus and availability file details. some of the packages are fully available and some of them are partially available. If this is partially available it takes at least two months to be completely available.
If you are a graduate or Ph.D. student, if you are a university professor or an expert engineer in the industry who deals with simulation software, you are definitely familiar with the limitations of this software in defining the material properties, loading or meshing, interaction properties, and etc. You have certainly tried to define the properties of materials based on advanced fracture theories in finite element software and are familiar with their limitations and problems. Now, here is your solution. Start writing subroutines in finite element software and overcome the limitations. With the tutorials in the Golden Package, you will learn how to write 8 subroutines in Abaqus software professionally.
Composite simulation for experts-Part-2
Pay attention to the syllabus and availability file details. some of the packages are fully available and some of them are partially available. If this is partially available it takes at least two months to be completely available.
If you are a researcher, student, university professor, or Engineer in the company in the field of composite materials, this training package in simulating these materials in Abaqus software is the best selection. This training package is the second part of the composite for expert package and is focusing on the Simulation of woven composite damage in Abaqus, Composite Fatigue Simulation, Analysis of Composite pressure vessel with Semi-Geodesic winding, Simulation of composite Hashin damage in 3d continuum element (UMAT-VUMAT-USDFLD), and Abaqus composite modeling of Woven & Unidirectional + RVE method.
Simulation of composite Puck damage in 3d continuum element in Abaqus (UMAT-USDFLD-VUMAT)
The Puck criterion is an essential damage model for composite materials, considering both fiber and matrix failures simultaneously. It provides a practical way to predict the onset of damage in composites under various loading conditions. This training package is focused on simulating composite PUCK damage in 3D continuum elements using UMAT, VUMAT, and USDFLD subroutines in Abaqus. It covers different types of failure in composites, including fiber failure, matrix cracking, delamination, and interfacial failure, as well as criteria for predicting failure modes in composites that are dependent or not dependent on each other, such as the Tsai-Wu and Tsai-Hill criterion, respectively. Additionally, the package covers composites' most commonly used damage criteria, including the Puck criterion. The package provides step-by-step guidance on simulating composite Puck damage using each of the subroutines mentioned above in Abaqus.
Simulation of woven composite damage in Abaqus
Woven composites are net-shaped composite structures that are fully interconnected by their yarns. Like a piece of cloth, the yarns are weaved together as warp and weft to create a composite structure. This package includes several components. First, it begins with an introduction to woven composites. Next, it provides a detailed explanation of macro modeling and offers guidance on how to perform it. The damage criteria employed in this package is a modified version of the Hashin criteria specifically designed for woven composites. Furthermore, the package demonstrates how to model damage using the USDFLD subroutine and Hashin relations. The subroutine is thoroughly explained, line by line, and a workshop is conducted to facilitate learning and practical application. Finally, the subroutine's validity is confirmed through a verification process.
Damage simulation of short fibre composites with subroutine
Short fiber composites consist of chopped fibers and a matrix, forming a discontinuous fiber-reinforced material, with fibers typically positioned either aligned or randomly within the matrix based on the intended application. In this training package, you will learn how to model the short fiber composite (SFC) damage in Abaqus based on this article: “Damage Modeling in Random Short Glass Fiber Reinforced Composites Including Permanent Strain and Unilateral Effect”. In the lesson one, you will learn the fundamentals such as the SFCs advantages, applications, and etc. Moving on to Lesson 2, the focus shifts to modeling Short Fiber Composites in Abaqus. The lesson introduces the critical decision between Macro and Micro modeling, which this package do a macro modeling. Lesson 3 advances the learning journey by exploring damage modeling in Short Fiber Composites, particularly through Dano's model. This macroscopic approach incorporates irreversible processes and internal variables, addressing anisotropic damage, unilateral effects, and residual effects. Lesson 4 bridges theory to practical application, guiding users on how to implement Dano's model in Abaqus through the VUSDFLD subroutine. The tutorial navigates through the subroutine's flowchart, explaining each line sequentially. Complementing the lessons are two workshops. Workshop 1 features a 2D composite plate with a hole using plane stress elements, offering a detailed breakdown of material properties, boundary conditions, and simulation procedures. Workshop 2, mirroring the first, employs shell elements, showcasing variations in element types while maintaining consistency with the utilization of the VUSDFLD subroutine.
Fatigue damage simulation of short fibre composites with subroutine
Fatigue failure in materials occurs when repetitive or fluctuating stresses, below the ultimate strength and often below the yield limit, lead to sudden and unpredictable failure, making it a significant concern in engineering due to its potential for catastrophic consequences. The reinforced part of the fiber-reinforced composites can be categorized as continuous or discontinuous, with the latter referred to as short fiber-reinforced composites. In this training package, the fatigue of short (chopped) fiber composites is explained. Two fatigue damage models are presented for short fiber composites: Nouri fatigue damage model and Avanzini fatigue damage model. The Nouri’s model is applicable for composites with orthotropic behavior. But the Avanzini’s model has considered the fiber distribution in the matrix to be homogeneous and random. It has assumed the material behavior to be isotropic. Also, Nouri's model was developed for strain-controlled test, but Avanzini's model was developed for stress-controlled test. In this tutorial, we use the Avanzini’s model, which is base on this article: “Fatigue behavior and cyclic damage of peek short fiber reinforced composites”. This article has implemented the USDFLD subroutine, but we use the UMAT subroutine, which is more accurate than USDFLD since the material strength and properties reduction is smooth. A standard test specimen is used in this simulation to model such behavior. You will learn the details in the package.
Simulation of cohesive fatigue in Abaqus with subroutine
Simulation of woven composite fatigue in Abaqus
The training package focuses on simulating woven composite fatigue using Abaqus software and the modified Hashin fatigue damage model based on the article titled "Life prediction of woven CFRP structure subject to static and fatigue loading ". Woven composites have high strength and stiffness-to-weight ratios, but the interlacing pattern can affect stress distribution and damage mechanisms, making fatigue analysis crucial. The package includes four lessons covering different types of composite fatigue models, material characterization, generalization of the failure model, and the implementation of the UMAT subroutine. Two workshops provide hands-on experience in implementing the UMAT subroutine on one element in cyclic tension and a complex model. Fatigue analysis predicts material behavior under cyclic loading and helps design safe and reliable structures.
Simulation of composite Hashin damage in 3d continuum element in Abaqus (UMAT-VUMAT-USDFLD)
In this training package, the 3D continuum HASHIN damage initiation model is prepared via three subroutines (USDFLD, UMAT and VUMAT).This training package teach you subroutines line-by-line. It should be noted that after damage initiation, failure occurs suddenly and in the form of a reduction in properties in the model. The HASHIN theory for this package is based on Kermanidis article titled” FINITE ELEMENT MODELING OF DAMAGE ACCUMULATION IN BOLTED COMPOSITE JOINTS UNDER INCREMENTAL TENSILE LOADING “.
Composite simulation for experts-Part-1
If you are a graduate or Ph.D. student, if you are a university professor or an expert engineer in the industry who deals with simulation software, you are definitely familiar with the limitations of this software in defining the material properties, loading or meshing, interaction properties, and etc. You have certainly tried to define the properties of materials based on advanced fracture theories in finite element software and are familiar with their limitations and problems.
Now, here is your solution. Start writing subroutines in finite element software and overcome the limitations. With the tutorials in the Golden Package, you will learn how to write 8 subroutines in Abaqus software professionally.
3D continuum Abaqus HASHIN progressive Damage for composite materials (VUMAT Subroutine)
This tutorial teaches how to simulate damage in 3d continuum composite materials in ABAQUS. As you know, Abaqus does not have any material model for 3d composite materials. So, the user needs to write a customized subroutine to simulate damage initiation and progressive damage for composite materials in ABAQUS. In this package, one of the most practical damage initiation criteria (Hashin) is used to detect failure. It should be mentioned that this subroutine includes gradual progressive damage based on the energy method. This complex subroutine could be used for static and dynamic problems.
Composite Fatigue Simulation with UMAT Subroutine in ABAQUS (unidirectional)
The composite fatigue training package completely teaches how to simulate and analyze a fatigue composite model with the help of UMAT Subroutine in Abaqus software. In this training package, we have provided all the files needed for your training, including articles, theories, how to write subroutines, and software settings.
Simulation of Unidirectional Composite Damage in ABAQUS
This package is about Unidirectional Composite Damage tutorial and applies various theories to initiate and progress damage in composite materials based on ABAQUS capabilities for different elements. As you know, according to the modeling done by the micro or macro method, the way of defining the Abaqus composite damage completely follows the separate method in ABAQUS. This training package is customized for Abaqus composite macro modeling. There are 5 different unidirectional composite examples to help you master unidirectional composite simulations and Abaqus composite laminate damage modeling. You can see the examples in the syllabus below.
Abaqus composite modeling of Woven & Unidirectional + RVE method
This training package provides comprehensive basic information and examples on for composite modeling in ABAQUS FEM software in accordance with subsequent packages. The methods of modeling these materials are in two ways: micro and macro, which vary according to the type of material selected and how they are used. Next packages focus on two modeling types professionally.
Implementation of Cohesive by interaction & element based methods in ABAQUS
This package teaches you how to choose the method and apply cohesive modeling for various simple and complex problems. The training package also teaches you how to define the basic geometry of the adhesive elements and how to define the mechanical behavior in elastic and damaged regions in ABAQUS FEM software.
