Overlapping Lattice Modeling for concrete fracture simulations using sequentially linear analysis

Abstract

Modeling concrete fracture is important in order to uncover accurately the sources of distress which lead to the damage or failure of structures. Many different numerical approaches have been used in the past employing either a smeared or a discrete cracking approach. Those models have difficulty in capturing the local nature of cracking, as well as the direction of crack propagation. Lattice modeling and peridynamics (PD) are some of the more recent nonlocal fracture simulation tools which possess advantages, such as ease of modeling and accuracy of crack propagation simulations with few key parameters. In this work, we employ an overlapping lattice approach, where the continuum is discretized using truss elements extending over a predefined horizon similar to the concept used in PD with the sequentially linear analysis technique. Simulation results for several reinforced concrete (RC) and un-RC tests demonstrate the ability to estimate crack propagation directions and widths accurately, with the proposed modeling approach also offering a rather simple and intuitive approach.The analytical simulation of concrete is very important for the structural engineering community as the key reasons of the aging infrastructure in many countries, creating billions of dollars' worth of repair and replacement costs, 1 are associated with concrete cracking. Computational models for structural concrete subjected to extreme and environmental loads must give results with reasonable accuracy for the performance evaluation, repair, strengthening of existing structures, or the design of modern ones. In this way, it is possible to attain economical engineering solutions.Starting from the 1960s, concrete finite element simulations were conducted in the two mainstream directions. The first approach was based on the adjustment of adjusting the material stiffness matrix (i.e., smeared crack concept) introduced by Rashid. 2 Later, Hillerborg 3 and Bažant and Oh 4 led the development of stress-displacement models, which were used to regularize mesh dependency through a characteristic length scale and the fracture energy. 5-7 There are essentially two methods for the smeared crack models, that is, rotational) 5,8 and fixed crack models 9,10 in order to estimate crack initiation and propagation directions. The main drawback of the continuum-based finite element modeling is the inability of representing the actual separation due to cracking and having to operate with average strains across a gauge length rather than with actual crack openings. The second approach for concrete fracture simulations is the use of discrete crack models by placing springs, interfaces, or contact elements between the finite elements to mimic the separation and crack opening. [11][12][13][14] Despite the apparent advantages of modeling, the cracks via discrete elements explicitly, the issues on identifying crack locations as à priori, remeshing, pre and postprocessing, and the necessity of defining different constitutive models for the cracks and continuum parts are...

A Review on the Developments of Peridynamics for Reinforced Concrete Structures

“…Aydin et al [6] have also used SLA with an overlapping lattice model. However, details of the model are not disclosed, and it is not clear which PD formulation was used (although it appears to be a bond-based model combined with truss models).…”

Numerical modeling of the tension stiffening in reinforced concrete members via discontinuum models

“…Furthermore, rigid-body-spring model, proposed by Kawai [16], was applied to analyze the crack propagation in reinforced concrete structures, where the concrete was represented via rigid bodies based on Voronoi diagrams, interconnected by springs [17]. Recently, a lattice-based approach was presented where the steel, concrete, and bond behaviors are explicitly modeled using overlapping truss elements to explore the structural response of reinforced concrete members [18,19]. In this research, an alternative computational modeling strategy is proposed by further extending the pioneering work of Lorig and Cundall [13], in which the tension stiffening phenomenon is numerically investigated via discontinuum models composed of large polyhedral blocks in 3D.…”

“…Figure18. Influence of different contact-constitutive models in the compression regime on the macro-response of the RC beam.…”

Overlapping Lattice Simulation of Concrete Gravity Dam Collapse Scenarios

“…The overlapping lattice approach employs pin connected bar elements extending over a predefined horizon to discretize the continuum similar to the concept used in peridynamics. OLM considers cracking by employing brittle or elastic-softening force displacement models [13,14]. Hence OLM has the potential to model crack initiation, opening and propagation naturally.…”

“…Hence OLM has the potential to model crack initiation, opening and propagation naturally. Aydin [15] conducted a detailed study to obtain the constitutive model properties of bar elements by employing direct tension test results. Further validation studies were conducted in that study by using sequentially linear analysis technique.…”