Hybrid and Virtual Experimentation for Infrastructure Lifecycle Maintenance and Natural Hazard Resilience

Introduction

Hybrid Simulation

Hybrid Simulation is an approach where a dynamic analysis of a structural system is performed by discretizing it into sub-structures. Each sub-structure can be solved separately through an analytical model or an experimental test, contributing at each time step to the formulation of the stiffness matrix. It is therefore challenging, since it requires in-depth knowledge of specialized experimental and analytical tools.

The whole analyis, is controlled with the use of a purpose-specific coordination software. UI-SimCor [1], is such a coordination software, developed by the research group at the University of Illinois, and is the first platform that has been used for multi-site testing of bridges including SSI phenomena.The basic concept of UI-SimCor is that analytical models of some parts of the structure or experimental specimens representing other parts of the same structure are considered as super-elements with many DOF. These elements, whether analytical or experimental, are treated on different networked computers and can be located anywhere in the world. Specially developed interface programs allow the interaction with different analysis software such as OpenSees, and ABAQUS.

[1] O.-S. Kwon, A. S. Elnashai, B. F. Spencer, and K. Park, “UI-SIMCOR : A global platform for hybrid distributed simulation,” in 9th Canadian Conference on Earthquake Engineering, 2007, no. June, pp. 139–149. 

Multi-platform simulation

Multi-platform simulation is also a promising alternative to the aforementioned Hybrid simulation approach, successfully applied for the assessment of real bridges in the US for various soil conditions [2]. It also permits the sub-structured analysis of a complex system using purely analytical tools (i.e. no physical testing is performed in contrast to the hybrid simulation application), that can be physically distributed all over the world, as in the previous case. The advantage of this approach is that the appropriate selection and combination of different analysis packages, enables the concurrent use of the most sophisticated constitutive laws, element types and features of each software package for each corresponding part of the soil-structure system. In other words, different software can be used for different system components depending on the foreseen inelastic material behaviour, level and nature of the seismic forces and the geometry of the particular problem. It is believed that this approach leads to combined capabilities that no finite element program currently provides, nor is probable to provide in the near future.

 [2] O.-S. Kwon and A. S. Elnashai, “Seismic analysis of meloland road overcrossing using multiplatform simulation software including SSI,” Journal of Structural Engineering, vol. 134, no. 4, pp. 651–660, 2008. 

Multi-platform network set-up

In the framework of the DeGrie lab project a distributing computing application was conducted between a computer from the Civil Engineering Departmnet of the Aristotle University of Thessaloniki and one from the Civil Engineering Departmnet of the Bauhaus University of Weimar.

The main objectives were:

- to perform a distributed computing analysis that could be used as an introductory example for students, and

- to prepare the appropriate communication set up so that any student could utilize the two computers and perform the example.

The theoretical backround of distributed computing, description of the studied structure and a manual, supplemented with video tutorials, are presented below.

Softwares used for the interconnection

HCOUPER-PC

Matlab 2011b (including Instrument Control Toolbox) • UI-Simcor v2.8 OpenSees solver

ALIANTE-PC

Abaqus v6.12 • Abaqus to UI-Simcor communication protocol (NICA.exe) • Cisco VPN Client (required for Remote Desktop Connection to HCOUPER)

The network established consists of two PCs, namely  HCOUPER-PC and  ALIANTE-PC. The former  is located in the Department of Civil Engineering of Aristotle University of Thessaloniki  and serves to Network Coordination  and  also to the analysis of the OpenSees-based modules.  The later is located  “Digital Bauhaus Lab” of  Bauhaus University of Weimar and serves for the analysis of the Abaqus-based modules. 

Case Study 1

For the validation of the developed multi-platform analysis network a case study analysis was used. More specifically, a thee-span bridge of a total length of 70 m (Fig. 1) was divided into three modules, two corresponding to the bridge abutments (right and left) and one to the main body of the bridge.

A preliminary 3D simulation in Abaqus was employed to derive the embankment-abutment stiffness (K=62500 kN/m). Based on the results of that simulation an equivalent rectangular beam section  with a width of 1.554 m  and a height of 9 m was defined in order to be used in the two abutment modules (Fig. 2).

According to the network previously described, ALIANTE-PC was used for the abutment modeling in Abaqus while HCOUPER-PC was used for the main body modeling in Openness as well as for the coordination of the whole process

Manual

Official documentation regarding the application of a Multi-platform simulation between Abaqus and OpenSees using UI-Simcor as the coordinator software, can be downloaded here

An additional tutorial was developed here that in contrast to the material prepared by the developers, this guide can be considered as an effort to reflect the perspective of the end-user.

The scope of this tutorial is to provide a quick-start guide for the use of the open-source computer code UI-Simcor, for the aforementioned studied bridge (Fig. 1).

The guide contains:

- Bridge geometry and material properties- Details for the preparation of the Abaqus files for the simulation of the left and right abutments 

- Details for the preparation of the OpenSees files for the simulation of the

- Details for the preparation of the SimCor file that coordinates the analysis 

Video Tutorials

Steps for Multi-platform simulation

You can also find all the following videos at our YouTube channel: DeGrie Lab

About

Dynamic response of bridges and infrastructure has been widely recognized in numerous research studies with assessing the importance of Soil-Structure-Interaction (SSI). This phenomenon is very complex and whether or not is beneficial …

 

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Partners

DeGrie Lab is a German/Greek association of the Bauhaus-University Weimar and the Aristotle University Thessaloniki. The project is supported by the German Academic Exchange Service.

German Academic Exchange Service
Bauhaus-University Weimar, Germany
Aristotle University Thessaloniki, Greece
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© de.grie Lab, a project of  Bauhaus-University Weimar, Germany  &  Aristotle University Thessaloniki, Greece