Over 10 billion tons of concrete are produced for the construction industry every year, making concrete the second most used substance on Earth, only surpassed by water. With such high importance as a building material, there is significant need for the ability to accurately model concrete behavior. As a quasi-brittle composite material, mechanical behavior is uniquely defined by a fracture process zone and various nonlinear damage phenomena. The Lattice Discrete Particle Model (LDPM) is a well-suited approach for capturing such response given its constitutive definitions and discretization at the mesoscale. LDPM has been extensively validated on experimental data and performs well for small to large concrete samples under most strain rates. This dissertation presents significant developments for LDPM, specifically focused on micromechanics, scaling, and dynamics, as well as improved usability for practitioners and researchers. New scripts and commercial finite element code implementation was developed and presented here to improve access to concrete numerical models. Micromechanically, a new model was developed: the Poly-Material Lattice Discrete Particle Model (P-LDPM), a multi-material model which can predict and upscale concrete information from the microscale, to miniscale, to mesoscale, and potentially have applicability for non-cementitious materials. Scaled geometrically, LDPM is utilized for examination of shear strength of large-scale squat shear walls, including energetic size effect and the implications of such for specification-based design. In dynamics, LDPM formulation is updated for simulation at very high strain rates, such as during detonation events. New models are also presented for implementation of reinforcing bars and plates with LDPM, and application of blast and pressure loads. As an application study, LDPM was also applied to a non-cementitous material for validation. Finally, various research endeavors were also undertaken to investigate new quasi-brittle materials, concrete fabrication techniques, structural design ideas, and performance of certain modern construction specifications.

Creator

• Troemner, Matthew

DOI

• https://doi.org/10.21985/n2-p2q0-0q09

Subject

• Materials Science
• Computational physics
• Civil engineering

Language

• en

Alternate Identifier

• etdadmin_upload_878306
• http://dissertations.umi.com/northwestern:15920

Keyword

• Lattice Discrete Particle Model
• Concrete
• Micromechanics
• Dynamics
• Numerical Models
• Size Effect

Date created

• 2022-01-01

Resource type

• Dissertation

Rights statement

• In Copyright