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Mr. David S. Riha
Principal Engineer
Email: driha@swri.org
Phone: (210) 522-5221
Fax: (210) 522-6965
Graduate studies, Ph.D. in Biomedical Engineering, University of Texas at San Antonio/University of Texas Health Science Center at San Antonio, 2003-present
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Mr. Riha began his employment at Southwest Research Institute in September 1988. His technical experience and interests are concentrated in the area of computational mechanics with emphasis in probabilistic structural analysis, finite element methods, and computer implementation of these techniques. He has over 30 publications in these areas.
Mr. Riha leads the NESSUS probabilistic analysis software development and application team. He is the lead software developer and coordinates the methodology, verification, quality assurance, and distribution of the software. He also leads many application efforts in the probabilistic analysis and design areas. He recently supported a probabilistic fracture mechanics analysis of a space shuttle main engine component in support of return to flight status of the shuttle fleet. He developed a probabilistic redesign methodology for vehicle crashworthiness involving interfacing advanced probabilistic algorithms with high-fidelity numerical models to predict the vehicle damage and occupant injury. Mr. Riha continually provides consulting for applied reliability problems for various industry and government agencies in areas such as aerospace, automotive, biomechanics, and geomechanics.
Mr. Riha currently leads several tasks supporting a project for the Los Alamos National Laboratory to develop advanced reliability prediction methods for application to weapon certification problems. In this project, major enhancements to the SwRI developed NESSUS probabilistic analysis program are being made to interface with complex weapon simulation programs running on massively parallel computer hardware.
He was a prime contributor to a Defense Special Weapons Agency (formerly Defense Nuclear Agency) project to evaluate the structural deformation and damage of deep underground tunnels subjected to ground shock. The PRONTO nonlinear explicit dynamic finite element computer program was used to model wave propagation through jointed rock. Advanced probabilistic algorithms were integrated with PRONTO to predict the probabilistic response and reliability of underground structures. His contributions included software development and integration, constitutive model verification, probabilistic analysis of the underground tunnels, and results interpretation. In a similar project for Eglin Airforce Base, Mr. Riha investigated the effect of spatial variations of material properties for predicting damage of buried tunnels subjected to penetrating weapons.
Mr. Riha was a key contributor to a large multi-year NASA sponsored research and development program entitled "Probabilistic Structural Analysis Methods (PSAM) for Select Space Propulsion System Components." The goal of this program was to analytically predict the probabilistic response and reliability of complex structures subject to various input uncertainties. The probabilistic structural risk assessment computer program, NESSUS, was initially developed under this program. He was responsible for the NESSUS software management and methodology implementation and validation
Mr. Riha has managed the annual short course entitled "Probabilistic Analysis and Design: Computational Methods and Applications" since 1996 and has been an instructor since 1991. He develops training material and conducts training classes in the area of probabilistic analysis and design and NESSUS software usage. He also contributes to a $9M project sponsored by the FAA to develop a probabilistic rotor design methodology and analysis code DARWIN. During his career at SwRI, he has lead and/or supported 5 internal research projects that focus on advanced computational techniques for probabilistic analysis, design and modeling.
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Professional Chronology
Southwest Research Institute: 1988-[student engineer, 1988-91; engineer, 1991-4; research engineer, 1994-7; senior research engineer, 1997-2003; principal engineer, 2003-present].
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Publications/Presentations
2009
Riha, D.S., R.C. McClung, and J.M. Mcfarland. Probabilistic Fracture Mechanics Guidelines and Templates.
Presented at the International Conference on Structural Safety and Reliability (ICOSSAR), Osaka, Japan, September 2009.
2008
Huyse, L.J., K.J. Smart, C.J. Waldhart, D.S. Riha, B.J. Bichon, A.P. Morris, and D.A. Ferrill. Quantification of Uncertainty in Reservoir-Scale Extensional Fault-Propagation Folds, Part 2: Probabilistic Modeling Results.
Presented at the American Association of Petroleum Geologists Annual Meeting, April 20-23, San Antonio, Texas, 2008.
Riha, D.S., B.H. Thacker, L.J. Huyse, M.P. Enright, C.J. Waldhart, W.L. Francis, D.P. Nicolella, S.J. Hudak Jr., W. Liang, and S.K. Fitch. Applications of Reliability Assessment for Aerospace, Automotive, Bioengineering, and Weapons Systems.
Smart, K.J., L.J. Huyse, A.P. Morris, D.A. Ferrill, D.S. Riha, and C.J. Waldhart. Quantification of Uncertainty in Reservoir-Scale Extensional Fault-Propagation Folds, Part 1: Finite Element Modeling Results.
Presented at the American Association of Petroleum Geologists Annual Meeting, April 20-23, San Antonio, Texas, 2008.
2007
Huyse, L.J., C.J. Waldhart, D.S. Riha, B.H. Thacker, C.E. Larsen, R.J. Gomez, and P.C. Stuart. Space Shuttle Debris Impact Assessment: Probabilistic Analysis and Model Verification and Validation.
Presented at the 48th AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics, and Materials Conference, Waikiki, HI, USA, 2007.
[Proceedings]
View All Publications
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Recent Projects
Probabilistic Tunnel Vulnerability Analysis
Develop a probabilistic hillside tunnel vulnerability model to identify the optimum targeting location considering functional failure due to rock commonition, airblast and fragmentation.
Probabilistic Blast Containment Vessel Analysis
Evaluate the reliability of blast containment vessels subject to dynamic pressurization and fragment impact.
Stochastic Crashworthiness Analysis
Develop a stochastic frontal car crash model and perform a reliability-based redesign to improve occupant safety due to a number of vehicle failure and occupant injury metrics.
Probabilistic Fracture Mechanics Analysis of Space Shuttle Flowliner
Develop deterministic and probabilistic fracture mechanics models to quantify the reliability of the space shuttle main engine flowliner.
Probabilistic Structural Analysis of Deep Tunnels
Develop probabilistic structural analysis methods and computational tools to assess the effect of uncertainties in loads, geologic properties, and initial conditions on the survivability and vulnerability of underground tunnels subject to near surface blast loading.
Probabilistic Structural Analysis Methods for Space Propulsion Components
Develop probabilistic structural analysis methods and computational tools to evaluate the reliability and risk of space propulsion system components such as turbine blades, transfer ducts, and liquid oxygen posts.
Probabilistic Assessment of Space Shuttle Debris Transport and Impact
Probabilistic assessment of the impact and damage to the space shuttle thermal protection system components.
Automotive Engine Crankshaft Reliability
Quantify the reliability and identify important design parameters of an automotive crankshaft subject to high-cycle fatigue
Space Shuttle External Tank Debris: Probabilistic Modeling & Analysis
The project objective is to convert existing analysis models and computer codes into an end-to-end probabilistic analysis tool for the assessment of external tank debris release, impact and damage to the orbiter. The tool was delivered to NESC and NASA.
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Contact Information |
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Carl F. Popelar, Ph.D.
Mechanics and Materials
(210) 522-4213
cpopelar@swri.org |
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Related Terminology |
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probabilistic analysis
reliability analysis
uncertainty quantification
life prediction
materials integrity
risk of failure
risk assessment
biomechanics
biomaterials
NESSUS
DARWIN
NASGRO
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