top of page


The Officers
Juan Manuel Mendez Franco
Juan Manuel Mendez Franco, 
President | Phone: +1.832.573.6168

Robert Zimmerman
Robert Zimmerman, P.E.
Vicepresident | Phone: +1.713.485.1062

Juan has 15 years of Piping Stress experience in project execution and construction for Oil and Gas Plants (Refineries, LNG and GTL), Floating Production, Storage and Offloading (FPSO), Platforms as well as Pharmaceutical, Chemical and Petrochemical Plants.

He has worked in several countries including Mexico, Germany, Singapore, Indonesia and USA for projects all over the world.


He currently works in Houston, Texas for the prestigious engineering and construction company Wood Group.

Bob has over 38 years of detailed engineering experience for refinery, petrochemical, cogeneration power, upstream and nuclear projects.

He has extensive experience in Pipe Stress Analysis and Pipe Support design.  Extensive use of FEA calculations to obtain more realistic and practical piping designs.  Performed all standard pipe stress calculations.  Performed special calculations for elevated temperature piping, reciprocating compressors, close coupled reboilers, reformer lines, expansion joints, slug flow, water hammer and numerous other non-standard pipe stress analyses.  Performed field engineering, inspections and HVEC reviews and audits both domestically and internationally.

Abimelech Salas Hernandez
Abimelech Salas Hernandez, 
Latin America Regional Director |

Phone: +1.832.897.4415

Abimelech Salas Hernandez
Antonio (Tony) Martinez,
Regional Director Western Europe & Technical Advisor |

Phone: +34.608.607.619

Abi is a B.S. Mechanical Engineer from ITCM in Mexico. Entrepreneur and business owner in Mexico and USA. More than 12 years of experience in pipe stress engineering developing and leading projects such as refineries, petrochemical, LNG plants and FPSO.

Abi has worked in large scale projects located in Australia, Algeria, Kazakhstan, Saudi Arabia, Mexico and USA.

He has participated in construction and maintenance projects in Mexico as Project Manager.

Tony has 22 years of Piping Engineering experience, with over 10 years as a Piping Stress Engineer. Tony has held leading positions on IPC projects and Oil & Gas, both in design and field construction phases, for new plants and revamp projects. Recently worked as a Senior Piping Stress Engineer in Madrid, Spain for Refinery milestone projects on Antwerp Refinery (Belgium) and Al-Zour Refinery (Kuwait).

Experienced in the collaboration and revision of Piping Stress Manuals, project standards, specifications and procedures. He has tutored and mentored young engineers in Piping Stress and Caesar II, his true passions.

Tony has a Bachelor’s Degree in Mechanical Engineering. He was born and raised in and around oil and refinery camps.

Sondre Luca Helgesen, MSc.
Scandinavia Regional Director|

Phone: +

Iñaki U. Muñoz de Cote, M.Mkt
Creative | Marketing Director |

Phone: +

Sondre has been a stress analyst for more than 15 years. The specialty is piping but is also working with pressure vessels and structural analysis. His experience covers most parts of the oil and gas-industry, everything from downhole to topside, and land-based refineries. He started his company, Stressman Engineering, in 2011. The company is based in Porsgrunn, Norway, which is about a couple of hours south of Oslo. Sondre has been lecturing pipe stress at the South East University of Norway, hosted CAESAR II courses with Hexagon and through Stressman Engineering Academy in Asia.

Iñaki is a brand design, strategist, and content creator based in Mexico City, working at the intersection of simplicity, aesthetics, and function to help companies express themselves through meaningful user experiences striving to build relevance at every touchpoint.


Jonathan Arana Garcia, MSc.
USA Regional Director |

Phone: +

Nikola Jacimovic, Ph.D.
Regional Director Central Europe 

Jonathan is a Senior Piping Stress Engineer with +20 years of experience in Oil & Gas and chemical industry. Along his career he has worked as Piping Stress Analyst, FEA analyst and Support Design Engineer; participating in several large and small scale EPC projects developing complex calculations for critical piping systems in upstream, refining, FPSO, LNG, and GTL plants around the world.

Nikola holds a Ph.D. in mechanical engineering awarded by the University of Belgrade and has an extensive background in piping and pressure vessel design and analysis. Over the course of his career, he has worked on basic and detail designs of important projects in the power, process, petrochemical, and metals industries. He has authored and co-authored over 25 scientific and engineering papers and is currently an RDG member of ASME B31.3 subgroup N. He is currently based in Italy.

Ryan Metcalf, Regional Director - USA

Ryan is the Manager of the North American office (Houston) of Dynaflow Research Group (DRG), providers of advanced engineering design and analysis services in Pipe stress, FEA, CFD, Fiberglass, FFS, Surge, Water hammer, AIV/FIV, Pulsation, Wind, Firewater, and Root Cause Analysis.


DRG also develops and supports two world class software applications including BOSfluids which focuses on surge and water hammer in piping systems, and BOSpulse which focuses on pulsation analysis in piping related to gas compressors and reciprocal pumps. 


Ryan has spent 30+ years in the development, management, and sales of engineering software solutions for the Oil & Gas, chemical, and petrochemical industries.


Prior to DRG, Ryan worked for Paulin Research Group for 10 years in various roles, and before that he worked for Mustang Engineering (now part of Wood plc).

The Speakers
Juan Manuel Mendez Franco
Matt Jaouhari, PMP, P.E. 
PD&P Global Deputy Chief and Stress Lead at Bechtel Oil, Gas & Chemical
Robert Zimmerman
Yuqing Liu, Ph.D, P.E.
Pipe Stress Specialist, Piping Vibration Specialist, Senior Stress Engineer III at Bechtel Oil, Gas, & Chemicals

Matt Jaouhari is a Functional Manager of Pipe Stress Engineering for Bechtel Oil, Gas and Chemicals located in Houston, TX, USA.


He is a Bechtel Distinguished Engineer in the area of pipe stress and vibration, hold a bachelor of process piping, professional engineering license and serves as a code committee member of ASME B31.3 subgroup “Design” and a functional piping team member of Process Industry Practice (PIP).


He has two patents and several ASME publications.

Dr. Yuqing Liu is a senior pipe stress and vibration specialist working for Bechtel Oil, Gas, and Chemical located in Houston, TX, USA.


He holds a Ph.D, professional engineer license and serves as code committee in ASME boiler and pressure vessel code (BPVC). He has more than 17 years of experience in pipe stress analysis, vibration analysis, thermal transient analysis, and nuclear class 1 analysis.


He has one patent and several ASME PVP papers.

Juan Manuel Mendez Franco
David Diehl, PMP, P.E. 
Director of Training at Intergraph, Training & Communications Executive, Leadership & Organizational Development
Arlene Chase - Hyspan2_edited.jpg
Arlene Chase
Outside Sales Manager & Technical Sales at Hyspan Precision Products

With over 32 years of engineering & technical support experience, He brings in-depth knowledge of applicable industry technology, both IT-related and operational, to the role of Training Director at Intergraph. During the course of his career, he has produced breakthrough results, significant ROI and competitive advantage for the organizations which he has worked with. 

He is a resourceful, articulate, results-oriented professional ,valued for proficiency in intercultural communication and educational leadership. He is pride of his ability to think critically in diverse climates, and on consistently creating high-quality programs for learners of all skills and backgrounds. He mobilizes critical interdepartmental resources to resolve complex learning issues in fast-paced learning environments—an education and problem-solving specialist.

Arlene Chase graduated with a BS, Ceramic Engineering Degree from Alfred University.  Before coming to Hyspan, Arlene served Domestic and International markets and as the OEM market manager for the Electrical Power industry. She started with Hyspan in 2005 as Senior Applications Engineer supporting sales representatives and customers with technical and product solutions.


She departed Hyspan for a short time working in the same industry as a Sales Manager – Market Development with Eagle Burgmann – Expansion Joint Solutions. Arlene returned to Hyspan in September 2017 as the Outside Sales Manager – Technical Sales.  She supports Hyspan sales representatives and customers with technical and product support and presents product design, force calculations and application of Hyspan products to educate and prevent misapplication of expansion joints.

BJ Willingham, CFA
Consultant at Chilton Capital Management
Photo Georg Naumann.jpg
Georg Naumann
CEO & Founder at Pipe Stress Inc.

B.J. began his career at Wachovia Bank in North Carolina, then moved to Houston in 1976 to join Criterion Investment Management Co. as an equity portfolio manager. Criterion grew to become one of the country’s premier investment firms, ultimately merging into Transamerica Corp. in 1989. B.J. served as Chief Investment Officer for Transamerica Mutual Funds until 1994, when he left to found his own firm, Willingham Asset Management, Inc. Willingham Asset Management and Texan Capital merged at the end of 2007.


Mr. Willingham received a Bachelors of Arts degree in Economics from Yale University and an MBA from Wharton School of Finance. B.J. has served on the boards and committees of numerous non-profit organizations. He holds the Chartered Financial Analyst designation, and is a member of The CFA Institute and the Houston Society of Financial Analysts. B.J. and his wife Delby have two grown daughters. He enjoys the outdoors and is an avid fly fisherman.

Georg Naumann has over 32 years of experience in piping design, stress analysis, and support design.  He has focused much effort on reconciling calculated results with field observations – where what happened in the field was not anticipated by calculations.


In both power and process industries around the world, Georg has led design/build efforts for new plants, plant modifications and updates.  He is active in auditing, troubleshooting, failure analysis, re-design, and vibration assessments. 


Clients range from small engineering firms to large corporations such as Siemens-Westinghouse, owners, and insurance companies in need of expertise or analysis.

Frank Bos - Partner, Consulting Manager, and Senior SME, Dynaflow Research Group

Frank Bos is a Partner at Dynaflow Research Group, where he leads a team of technical consultants dedicated to providing practical engineering solutions for complex industrial projects. With over 15 years of experience, Frank's expertise includes advanced static and dynamic pipe stress analysis (including FEA), piping vibrations, water hammer, pulsation analysis, and Computational Fluid Dynamics (CFD). Frank and his team serve clients worldwide, working on complex design and analysis projects and problems across many industries such as Oil and Gas, LNG, geothermal, carbon capture, and offshore sectors including large FPSOs.

Need more details? Contact us

We are here to assist. Contact us by phone, email or via our Social Media channels.

bottom of page