March 28, 2008
Exponent Engineer Appointed Principal Member of Two NFPA Technical Committees
Dr. Xiaobo Yao, an Engineer in the Thermal Sciences Practice in the Bowie, Maryland office, was recently appointed as a principal member of two National Fire Protection Association (NFPA) Technical Committees: Flash Fire Protective Garments, and Water Mist Fire Suppression Systems. The committee for Flash Fire Protective Garments is responsible for NFPA 2112, Standard on Flame-Resistant Garments for Protection of Industrial Personnel Against Flash Fire; and NFPA 2113, Standard on Selection, Care, Use, and Maintenance of Flame-Resistant Garments for Protection of Industrial Personnel Against Flash Fire. The committee for Water Mist Fire Suppression Systems has primary responsibility for documents on the design, installation, and maintenance of systems which use a water mist for the control, suppression, or extinguishment of fire. The committee is responsible for NFPA 750, Standard on Water Mist Fire Protection Systems. More information on NFPA can be found at the NFPA website.
March 24, 2008
Exponent Engineer Co-authored Paper in the Society of Petroleum Engineers Journal
Dr. Brun Hilbert, Senior Managing Engineer in Exponent’s Mechanical Engineering and Materials/Metallurgy practice, co-authored a paper on modeling Teflon seal rings in oil and gas well threaded connections, which has been published in the Society of Petroleum Engineers (SPE) Journal.
Abstract
This paper presents new technology for evaluating high-pressure gas-seal integrity of polymer ring seals used as secondary or backup pressure seals in casing and tubing threaded connections. This new technology may also enable the further consideration of API connections with ring seals, as an alternative to premium connections, for appropriate applications. A nonlinear elasto-viscoplastic constitutive model for the behavior of polymers and elastomers has been developed and extended to the specific application of analysis of casing and tubing connections with fiberglass-filled PTFE ring seals. Procedures for modeling makeup of a connection including a fiberglass-filled PTFE ring seal have been developed using a finite-element model (FEM) of 10¾-in. OD, 45.5 lb/ft, P-110 API buttress thread casing-seal ring groove (BTC-SRG). The results of finite-element analysis (FEA) of makeup, followed by the application of thermal, axial, and internal pressure loads are presented in this paper. In addition, based on the interest in the development of gas-tight threaded connections for expandable casing, the FEM was subjected to a radial expansion of a 20% increase in the outside diameter. In this paper, the theory of the constitutive model is summarized and calibration of the model with experimental test and published data are presented. The focus of the FEA results is on the contact pressures between the ring seal, coupling groove, and pin threads.
Exponent Engineer Publishes Article in Environmental Finance
Robert Montgomery, Senior Managing Engineer in our Washington, DC office, published an article in the March 2008 issue of Environmental Finance. ”Managing Risk and Adding Value” discusses the concept of environmental risk management in financing large private sector projects. Bob recently joined Exponent after 10 years as head of the environmental and social unit of the Inter-American Development Bank private sector department. More information on the article can be found at www.environmental-finance.com.
March 13, 2008
Exponent Authors Published in SAE’s 2007 Transactions
Mr. Donald Parker, Dr. Rose Ray, Dr. Tara Moore, and Mr. Richard Keefer’s recent paper, “Rollover Severity and Occupant Protection—A Review of NASS/CDS Data,” will be published in March in SAE’s 2007 Transactions. Their paper was judged to be among the most outstanding SAE technical papers of 2007. Details concerning Transactions are available at www.sae.org/transactions.
Avoiding Structural Failures during Construction
 David Peraza, P.E., Senior Managing Engineer in Exponent’s Civil/Structural Engineering practice, and Dennis McCann. Ph.D., P.E., Managing Engineer also in the Civil/Structural Engineering practice, recently published the second part of the series of articles on “Avoiding Structural Failures during Construction” in the February 2008 edition of Structures Magazine. The article deals with failures of permanent structures and presents engineering principles and “lessons learned” that can be used by designers, owners and construction managers to minimize the probability of unfortunate events.
The article can be accessed on the Structure Magazine website.
March 06, 2008
Exponent Scientist named Fellow of AIHA
David Dahlstrom, CIH, Senior Managing Scientist in the Center for Public Health & Industrial Hygiene, has been named a Fellow of the American Industrial Hygiene Association (AIHA). AIHA is one of the largest international associations serving the needs of occupational and environmental health professionals practicing industrial hygiene in industry, government, labor, academic institutions, and independent organizations. Only five percent of the AIHA membership can qualify for the Fellow Award, which is given to those individuals who have made significant contributions to the field of industrial hygiene. More information can be found at www.aiha.org.
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