A Computational Framework Enabling Comparative Analysis of Progressive Damage Models for Composite Materials

Author(s):  
N. A. Apetre ◽  
J. G. Michopoulos ◽  
A. P. Iliopoulos ◽  
J. C. Steuben ◽  
N. Phan

Abstract The present work is motivated by the need for an efficient and quantifiable assessment of how various strain- or stress-based composite materials failure criteria and damage evolution models that capture the load-induced material degradation, along with their intrinsic parameters, can affect our understanding of material behavior and facilitate suitability decisions of such criteria. The difficulty of performing comparative analysis among many of these criteria and models has been a significant impediment to the composite materials design and material certification communities. In response to these needs, the present work describes the development, verification and validation of such a general computational framework. This framework enables not only increasing the user’s understanding of the effect of parameters associated with models under consideration on the model predicted results but also allowing the user to address more advanced problems such as material design, optimization and potentially certification. The framework implemented into “COMSOL Multiphysics” utilizes symbolic algebra to automatically generate the required expressions to be used in the respective computational modules. Two strain-based models for two distinct specimen geometries are used to show the framework capabilities: one model is described by three damage modes and a second one is given by four damage modes. The first geometry is that of a unnotched coupon whereas the second is that of an open hole specimen in tension. The theoretical predictions are compared with the experimental ones in terms of load-strain responses. The results indicate that by proper selection of specific input parameters, these models can accurately predict the structural response of composite laminate structural systems up to failure.

2021 ◽  
Author(s):  
Nicole Apetre ◽  
John Michopoulos ◽  
Athanasios Iliopoulos ◽  
John Steuben ◽  
Nam Phan

2021 ◽  
Vol 5 (2) ◽  
pp. 36
Author(s):  
Aleksander Muc

The main goal of building composite materials and structures is to provide appropriate a priori controlled physico-chemical properties. For this purpose, a strengthening is introduced that can bear loads higher than those borne by isotropic materials, improve creep resistance, etc. Composite materials can be designed in a different fashion to meet specific properties requirements.Nevertheless, it is necessary to be careful about the orientation, placement and sizes of different types of reinforcement. These issues should be solved by optimization, which, however, requires the construction of appropriate models. In the present paper we intend to discuss formulations of kinematic and constitutive relations and the possible application of homogenization methods. Then, 2D relations for multilayered composite plates and cylindrical shells are derived with the use of the Euler–Lagrange equations, through the application of the symbolic package Mathematica. The introduced form of the First-Ply-Failure criteria demonstrates the non-uniqueness in solutions and complications in searching for the global macroscopic optimal solutions. The information presented to readers is enriched by adding selected review papers, surveys and monographs in the area of composite structures.


2017 ◽  
Vol 755 ◽  
pp. 300-321 ◽  
Author(s):  
Volodymyr I. Korsun ◽  
Yu.Yu. Kalmykov ◽  
S.Yu. Makarenko

The paper is about the generally accepted in the deformable solid mechanics principles of constructing limiting surfaces of concrete strength in the principal stress space. The background and theoretical approaches taken by different researchers to describe the functions of deviatoric and meridional curves as the basic elements which determine the surface configuration of concrete strength were analyzed.There was carried out a comparative analysis of different authors’ suggestions on an analytic description of concrete strength for different stress states and a comparison of the developed criteria and the results of short-term tests of plane concrete under multiaxial loadings. Comparing the methods taken for developing the interpolation functions of deviatoric and meridional curves, it was inferred that the application of different approaches to the development of concrete failure criteria is effective. Keeping in mind the results of the comparative analysis of the prerequisites taken to develop the above failure criteria and the requirements of a better approximation of the experimental data, there are made new suggestions to describe concrete strength for the general case of stress state.


2015 ◽  
Vol 813-814 ◽  
pp. 106-110
Author(s):  
Dalbir Singh ◽  
C. Ganesan ◽  
A. Rajaraman

Composites are being used in variety of applications ranging from defense and aircraft structures, where usage is profuse, to vehicle structures and even for repair and rehabilitation. Most of these composites are made of different laminates glued together with matrix for binding and now-a-days fibers of different types are embedded in a composite matrix. The characterizations of material properties of composites are mostly experimental with analytical modeling used to simulate the system behavior. But many times, the composites develop damage or distress in the form of cracking while they are in service and this adds a different dimension as one has to evaluate the response with the damage so that its performance during its remaining life is satisfactory. This is the objective of the present study where a hybrid approach using experimental results on damaged specimens and then analytical finite element are used to evaluate response. This will considerably help in remaining life assessment-RLA- for composites with damage so that design effectiveness with damage could be assessed. This investigation has been carried out on a typical composite with carbon fiber reinforcements, manufactured by IPCL Baroda (India) with trade name INDCARF-30. Experimental studies were conducted on undamaged and damaged specimens to simulate normal continuous loading and discontinuous loading-and-unloading states in actual systems. Based on the experimental results, material characterization inputs are taken and analytical studies were carried out using ANSYS to assess the response under linear and nonlinear material behavior to find the stiffness decay. Using stiffness decay RLA was computed and curves are given to bring the influence of type of damage and load at which damage had occurred.


1998 ◽  
Vol 26 (2) ◽  
pp. 89-110 ◽  
Author(s):  
R. A. W. Mines

The paper describes a final-year undergraduate course that has been taught at the University of Liverpool for the past three years. The main aims of the course are to introduce the student to the design of structures using multi-component (composite) materials and to the performance of such structures under impact loading. Given the complexity of generalized composite behaviour and of structural crashworthiness, a simple structural case is considered, namely, a beam subject to three-point bending. A feature of the course is that not only is linear structural response considered but also non-linear (progressive) structural collapse is covered. The course is split into four parts, namely: (i) analysis of composite laminae, (ii) analysis of laminated beams, (iii) local and global effects in sandwich beams, and (iv) post-failure and progressive collapse of sandwich beams. Static and impact loadings are considered. Comments are made on how the theories are simplified and communicated to the undergraduate students.


2018 ◽  
Vol 16 (6) ◽  
pp. 869-888 ◽  
Author(s):  
Siddharth Kulkarni ◽  
David John Edwards ◽  
Erika Anneli Parn ◽  
Craig Chapman ◽  
Clinton Ohis Aigbavboa ◽  
...  

Purpose Vehicle weight reduction represents a viable means of meeting tougher regulatory requirements designed to reduce fuel consumption and control greenhouse gas emissions. This paper aims to present an empirical and comparative analysis of lightweight magnesium materials used to replace conventional steel in passenger vehicles with internal combustion engines. The very low density of magnesium makes it a viable material for lightweighting given that it is lighter than aluminium by one-third and steel by three-fourth. Design/methodology/approach A structural evaluation case study of the “open access” Wikispeed car was undertaken. This included an assessment of material design characteristics such as bending stiffness, torsional stiffness and crashworthiness to evaluate whether magnesium provides a better alternative to the current usage of aluminium in the automotive industry. Findings The Wikispeed car had an issue with the rocker beam width/thickness (b/t) ratio, indicating failure in yield instead of buckling. By changing the specified material, Aluminium Alloy 6061-T651 to Magnesium EN-MB10020, it was revealed that vehicle mass could be reduced by an estimated 110 kg, in turn improving the fuel economy by 10 per cent. This, however, would require mechanical performance compromise unless the current design is modified. Originality/value This is the first time that a comparative analysis of material substitution has been made on the Wikispeed car. The results of such work will assist in the lowering of harmful greenhouse gas emissions and simultaneously augment fuel economy.


Author(s):  
Michael G. Jenkins ◽  
Paul E. Labossie`re ◽  
Jonathan A. Salem

Ceramic matrix composites (CMCs) have evolved to exhibit inherent damage tolerance through nonlinear energy absorption mechanisms while retaining the desirable attributes of their monolithic structural ceramic counterparts. Mathematical (analytic and numeric) models together with experimental measurements of this damage absorption have aided in understanding the thermomechanical behavior of CMCs. This understanding has led to improved test methods, better predictive modeling of material behavior, appropriate processing methods, and finally novel design methodologies for implementing CMCs. In this paper, background on CMC damage is presented, damage measurement and damage models are discussed and finally probabilistic aspects of constituent materials that can be used to illustrate the cumulative damage behavior of CMCs are described.


Author(s):  
Sanjeev K. Khanna ◽  
Marius D. Ellingsen ◽  
Robb M. Winter

Composite materials are widely used in mechanical structures where a high ratio of strength or stiffness to weight is desired. Not only are composite materials widely used in building recreational equipment such as skis, snowboards or even sports cars, but also multiple types of military aircraft are built from composite materials. Airplane bodies are in principle cyclically loaded pressure vessels and are susceptible to the formation of fatigue cracks, and it is necessary to possess knowledge of how the material behaves with a crack present. In fact, all engineering structures have to be designed with the presence of crack like defects in mind. For traditional engineering materials such as steel and aluminum there exists a large body of knowledge regarding material behavior in the presence of a crack. Furthermore, their isotropic nature eases the process of mechanical analysis. Photoelasticity, an optical method, has been widely used to study fracture in isotropic transparent materials (Irwin, 1962, 1980; Dally, 1979; Daniel, 1984; Kobayashi, et al, 1973; Chona, 1987).


Author(s):  
Shuangqiang Liang ◽  
Chenglong Zhang ◽  
Ge Chen ◽  
Qihong Zhou ◽  
Frank Ko

The stress concentration caused by notches is a common engineering issue for composite structure application. 3D braided composite possess excellent damage tolerance compared to common laminates. The tensile properties of 3D braided composite with open-hole and un-notched were experimentally examined. The mechanic properties of 3D braided composite in other directions are predicted using FGM (Fabric Geometry Model) and finite element analysis. The stress distributions around the hole and perpendicular to the loading direction are analyzed based on Abaqus software. The simulation results were compared with Lekhnitskii's analytical study. The open-hole strength of 3D braided composite was predicted respectively using Average stress failure criteria, Point stress failure criteria (PSC), and also the progressive failure analysis based on different failure criteria. The predicted strength results were compared to the experimental values. The results show the PSC predicted strength matched the experiment, while the progressive failure analysis can predict the failure initiation, propagation and final failure mode.


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