Complex Loadings Archives

Porting SI's ANACAP Concrete Model into LS-DYNA Advanced Structural Analysis

News & Views, Volume 50 | Porting SI’s ANACAP Concrete Model into LS-DYNA

October 6, 2021/in Code Compliance, Company News, Complex Loadings, Livio Mello, News and Views, Shari Day/by Structural Integrity

ADVANCED STRUCTURAL ANALYSIS

By: Livia Mello and Shari Day

One of Structural Integrity Associates’ (SI) strengths is combining state-of-the-art software with material science expertise to solve difficult structural and mechanical problems. A notable example in recent years is the Aircraft Impact Analysis (AIA) performed by SI for NuScale Power, using the ANACAP concrete material model. With SI’s support, NuScale’s Small Modular Reactor (SMR) building design passed NRC’s comprehensive inspection, bringing NuScale’s SMR technology one step closer to market [N&V Vol. 47 p. 5].

SI’s success in AIA is due not only to our team’s capabilities but also due to the capabilities of our proprietary concrete constitutive model, ANACAP, developed by Joe Rashid, Robert Dunham, and Randy James of ANATECH, now part of SI. Modeling reinforced concrete, which is both nonhomogeneous and anisotropic, is often a challenge in advanced structural analysis. However, ANACAP has a long track record of accurately capturing nonlinear concrete response in structural systems subjected to static, impact, and seismic loads. Its application goes beyond AIA; it has also been utilized in several of SI’s commercial building, bridge infrastructure, nuclear plant, and hydroelectric facility projects.

ANACAP has the ability to account for cyclic degradation, multi-axial cracking, load-rate effects, aging, creep, shrinkage, crushing, confinement, concrete-reinforcement interaction, and high-temperature softening behavior. The combination of these features results in an exceptional representation of concrete intricate behavior. It also leads to more accurate results when compared to standard finite element “built-in” concrete material libraries, all the while being implemented within the same standard finite element formulation.

News & Views, Volume 48 | SI Supports Parsons’ “DetectWise” Modular COVID Test Facility

September 30, 2020/in Complex Loadings, Critical Structures, News and Views, TRU Compliance/by Structural Integrity

By: Zach Withall and Matthew Naugle, PE

The health facility is designed to fully separate patients from medical workers, protecting both parties and minimizing the PPE required to operate the suite.

COVID-19 has presented humanity with unprecedented challenges. As economies reopen, solutions are needed that allow businesses to operate while protecting the health, safety, and security of the general public.

In an effort to positively impact that change, Structural Integrity Associates (SI) is working with Parsons Corporation, a global technology leader, to design a self-contained, mobile health screening facility for rapid, efficient and scalable testing.

The mobile facility is part of Parsons’ DetectWise™ suite of health solutions meant to combat the COVID-19 pandemic. SI provided structural design services for the facility.

News & Views, Volume 45 | Improved Asset Management Through Test Informed Analysis

January 1, 2019/in Complex Loadings, Critical Structures, Eric Kjolsing, Hydroelectric Power, News and Views, Structural Assessments/by Structural Integrity

By: Eri Kjolsing

Introduction
Structures may experience unforeseen operating environments or site-specific hazards leading to changes in the structure’s performance, safety, and longevity. These changes often prompt asset owners to undertake analysis efforts to ensure satisfactory structural performance for the updated conditions. However, conventional analyses that fail to capture the true behavior of a structure can lead to inaccurate analysis results, causing owners to make less than ideal asset management decisions. Structural Integrity (SI) is uniquely positioned to pair our dynamic characterization and advanced structural analysis capabilities to generate a better structural model. SI vibration experts use impact testing, forced vibration, or ambient excitation sources, along with proprietary signal processing software, to non-destructively characterize the dynamic behavior of structural systems. This characterization is used to inform advanced structural analyses by SI analysis experts to provide more accurate results related to operational improvements, damage location, and retrofits.

News & View, Volume 43 | Perforation, Scabbing, and Reinforcement Optimization in an Aircraft Impact Analysis (AIA)

News & Views, Volume 43 | Perforation, Scabbing, and Reinforcement Optimization in an Aircraft Impact Analysis (AIA)

October 5, 2017/in Complex Loadings, Critical Structures, Eric Kjolsing, News and Views/by Structural Integrity

By: Eric Kjolsing

Background
A 2016 project utilized a variety of Structural Integrity competencies to analyze a beyond design basis threat at an overseas nuclear power plant. The client was assessing a plant design and approached Structural Integrity to investigate local perforation and scabbing of a reinforced concrete wall due to hard missile impact. Perforation occurs when a missile fully penetrates and passes through a target while scabbing occurs when material is ejected from the back face of a target, potentially striking personnel and equipment inside the facility. The client also sought to reduce the volume of wall reinforcement, a potentially large cost savings, while still meeting the facility’s strict design criteria. The project is best described in four stages and took advantage of our AIA experience, finite element (FE) modeling expertise, and proprietary concrete constitutive model ANACAP.

News & Views, Volume 43 | Advanced Structural Analysis

October 5, 2017/in Complex Loadings, Critical Structures, Eric Kjolsing, Hydroelectric Power, News and Views, Structural Assessments/by Structural Integrity

By: Eric Kjolsing & Philip Voegtle

The sophistication of structural analysis has evolved side-by-side with computing and graphics technology. Structural engineers have at their fingertips very powerful software analysis tools that assist them in evaluating very large and complex structures for stability, suitability, and code adequacy. The tools themselves vary in complexity in proportion with the engineering analysis required of them – the most complex and unique engineering problems requiring the most advanced analysis tools. Structural Integrity is a leader in advanced structural analysis (ASA), utilizing state-of-the-art software and material science expertise to solve an array of structural and mechanical problems.

Structural analysis, in its most basic definition, is the prediction of the structural performance of a given structure, system, or component to prescribed loads, displacements, and changes in temperature. Common performance characteristics include material stresses, strains, forces, moments, displacements and support reactions. The results from a structural analysis are typically compared to acceptable values found in design codes. Meeting the design code acceptance criteria ensures a design that protects the public’s health, safety, and welfare.

ASA extends this basic definition of structural analysis to one-of-a-kind problems where the acceptance criteria may not be well defined. Since loads, material behavior, or the structure itself can go beyond the scope of basic design codes, ASA requires an in-depth understanding of modeling techniques, software limitations, and non-linear material behavior. In ASA, sophisticated finite element analysis solvers are utilized to gain a detailed understanding of a system’s non-linear mechanical behavior, providing a full three-dimensional view of the critical stresses and strains in a loaded system.