[ { "id": "authors:s2mxr-32359", "collection": "authors", "collection_id": "s2mxr-32359", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140612-082336397", "type": "article", "title": "General Confinement Model Based on Nonlocal Information", "author": [ { "family_name": "Cho", "given_name": "In Ho", "clpid": "Cho-In-Ho" }, { "family_name": "Hall", "given_name": "John F.", "orcid": "0000-0002-7863-5060", "clpid": "Hall-J-F" } ], "abstract": "The confinement effect has been of significant importance for improving the resilience against extreme compression loadings such as seismic excitations. Notwithstanding the accuracy of previous confinement models, some challenges remain regarding their applicability. The previous approaches often build on structure-dependent parameters necessitating intractable calibrations, and their formulations are defined on an integration point or a small portion of the structure, thereby precluding general applicability to complicated real-scale RC structures. Here a general confinement model is proposed in a novel way that it can harness physical information inside the real-scale system. The information is denoted nonlocal information, since it is processed by the nonlocal formulation for assuring the mesh-objectivity. Physically, the nonlocal information provides the proximity to adjacent stiff materials and boundaries through the information index suggested herein. Numerical issues regarding the parallel computing and the optimal selection of the length parameter for the nonlocal formulation are also addressed. The unprecedentedly broad applications include a solid column, a hollow column, a rectangular wall, a T-shaped wall, and even a wall with opening, which strongly bear out the promising potential and universality of the novel confinement model.", "doi": "10.1061/(ASCE)EM.1943-7889.0000724", "issn": "0733-9399", "publisher": "American Society of Civil Engineers", "publication": "Journal of Engineering Mechanics", "publication_date": "2014-06", "series_number": "6", "volume": "140", "issue": "6", "pages": "Art. No. 04014026" }, { "id": "authors:7w2my-fty21", "collection": "authors", "collection_id": "7w2my-fty21", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20130321-130810515", "type": "article", "title": "Virtual Earthquake Engineering Laboratory Capturing Nonlinear Shear, Localized Damage and Progressive Buckling of Bar", "author": [ { "family_name": "Cho", "given_name": "In Ho", "clpid": "Cho-In-Ho" } ], "abstract": "We embarked upon developing a novel parallel simulation platform that is rooted in microphysical mechanisms. Primarily aiming at large-scale reinforced-concrete structures exposed to cyclic loading, we sought to settle the question as to how to capture nonlinear shear, localized damage and progressive buckling of reinforcing bar. We proposed a tribology-inspired three-dimensional (3-D) interlocking mechanism in the well-established framework of multidirectional smeared crack models. Strong correlation between random material property and localized damage has been shown, notably at the global system level. An automated platform has been suggested to capture progressive buckling phenomena. Validation and applications straddle a wide range, from small laboratory tests to large-scale 3-D experiments, successfully offering a clear causal pathway between underlying physical mechanisms and the unresolved issues addressed above.", "doi": "10.1193/1.4000095", "issn": "8755-2930", "publisher": "Earthquake Engineering Research Institute", "publication": "Earthquake Spectra", "publication_date": "2013-02", "series_number": "1", "volume": "29", "issue": "1", "pages": "103-126" }, { "id": "authors:xrr1f-fby16", "collection": "authors", "collection_id": "xrr1f-fby16", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20120608-145954084", "type": "article", "title": "Parallelized Implicit Nonlinear FEA Program for Real Scale RC Structures under Cyclic Loading", "author": [ { "family_name": "Cho", "given_name": "In Ho", "clpid": "Cho-In-Ho" }, { "family_name": "Hall", "given_name": "John F.", "orcid": "0000-0002-7863-5060", "clpid": "Hall-J-F" } ], "abstract": "Parallel computing in civil engineering has been restricted to monotonic shock or blast loading with explicit algorithm which is characteristically feasible to be parallelized. In the present paper, efficient parallelization strategies for the highly demanded implicit nonlinear finite-element analysis (FEA) program for real scale reinforced concrete (RC) structures under cyclic loading are proposed. Quantitative comparison of state-of-the-art parallel strategies in terms of factorization were carried out, leading to the problem-optimized solver, which successfully embraces the penalty method and banded nature. Particularly, the penalty method employed imparts considerable smoothness to the global response, which yields practical superiority of the parallel triangular system solution over those of advanced solvers such as the parallel preconditioned conjugate gradient method. Other salient issues on parallelization are also addressed. By virtue of the parallelization, the analysis platform offers unprecedented access to physics-based mechanisms and probabilistic randomness at the entire system level and realistically reproduces global degradation and localized damage, as reflected from the application to a RC structure. Equipped with accuracy, stability and scalability, the parallel platform is believed to serve as a fertile ground for the introducing of further physical mechanisms into various research fields, as well as the earthquake engineering community.", "doi": "10.1061/(ASCE)CP.1943-5487.0000138", "issn": "0887-3801", "publisher": "American Society of Civil Engineers", "publication": "Journal of Computing in Civil Engineering", "publication_date": "2012-05", "series_number": "3", "volume": "26", "issue": "3", "pages": "356-365" } ]