About Openso Engineering

Providing Optimum Engineering Solutions

Openso Engineering is a specialized engineering services and fabrication technology company that serves the Petroleum Refining, Petrochemical, Chemical, and related industries.   We are centrally located in the United States near St. Louis, across the Mississippi River in Edwardsville, Illinois.

Our competitive advantage is the ability to combine the latest technology available with many years of practical experience analyzing, designing, and fabricating pressure vessels, heat exchangers, and other process equipment. This combination of technical aptitude and hands on knowledge allows us to react to our customers needs quicker and pinpoint the root cause of problems much faster. This time savings results in overall cost savings to our customers.


OPENSO was founded by four principal employees of Nooter Fabricating with over 120 total years of experience. If you are familiar with NFI, it was a world-renowned fabricator of pressure vessels, heat exchangers, and other process equipment.

Nooter was a pioneer in pressure vessel fabrication, which included fabricating the FIRST TWO ASME SECTION VIII Div 2 Pressure vessels ever manufactured. Our fabrication experience is one of the main advantages we have over our competition, because it allows us to develop a wider range of practical solutions to design issues and failures. Our President, Khalil Rabiei, was the Chief Engineer for Nooter Fabricators Inc. (NFI) and Engineering Manager for Nooter Consulting Services (NCS).

Management Team

Click on a name to learn more about that person:

Khalil Rabiei, President & Principal Engineer

Khalil Rabiei is the Principal Engineer for Openso Engineering.  He has Bachelor of Science, Engineering Mechanics and Material, Southern Illinois University at Carbondale, Master Of Science in Structural Engineering, Southern Illinois University at Carbondale, Post graduate studies in advance Structures at Washington University, St. Louis, MO.  He is a registered Professional Engineer in the states of Illinois, Missouri, Texas, California, Indiana, Ohio, and District of Columbia.  Khalil is also a part time staff member of Southern Illinois University at Edwardsville – Instructor of Mechanical Engineering Department.

Khalil is involved with many professional societies, including:

  • American Society of Mechanical Engineers
  • American Society of Civil Engineers
  • American Society of Professional Engineer
  • American Petroleum Institute (API) Member:
    • Design Committee
    • Joint Committee
    • Fitness for Service Committee

As Principal Engineer for Openso Engineering, Khalil’s leadership helps to guide a project from conception to completion:  consisting of initial technical proposal, quotation for total cost and turnaround time, conducting and performing design and analyses for highly complex problems using linear and non-linear methods, in both classical and finite element approaches, such as: stress/fatigue analysis, vibration analysis, and creep analysis of structures, performing classical discontinuity stress/fatigue analysis, thermal and thermal stress analysis, vibration analysis of structures under wind, seismic and any other dynamic loads.

A List of Khalil’s Publications:

  • Stability of Geodesic Dome Under Symmetric Dynamic Loads.  ASCE April 1995
  • Influence Of Imperfections On Nonlinear Dynamic Response Of Trusses.  ASCE April 1996 
  • Comparison of Dynamic Nozzle Loads to Static Nozzle Loads Using Finite Element Analysis, The International Association for the Engineering Analysis Community (NAFEMS) April 2001.
  • The Response of Framed Steel Structure.  Structures Congress 2006
Sepi Sayeh, Chief Financial Officer
  • Bachelor of Science in Electrical Engineering, Southern Illinois University-Edwardsville, 1994
  • Master of Science in Electrical Engineering, Southern Illinois University-Edwardsville, 1997
  • Chief Financial Officer of Openso Engineering since 2002
Jon Solomon, Sales/Project Manager
  • Bachelor of Science in Mechanical Engineering, University of Missouri-Columbia, 1993
  • Masters in Business Administration, Webster University, 2005
  • Deltak – Mechanical/Thermal Engineer, Piping Engineer – 1997-2000
  • Nooter/Eriksen – Pipe Stress Engineer, Project Engineer – 2005-2015
Sri Garapati, Principal Engineer

Sriharsha (Sri) Garapati is a Principal Engineer at Openso Engineering. Sri completed his doctoral degree in Mechanical Engineering at University of South Florida (USF), Tampa. During graduate school, Sri conducted research on variety of topics which include transient thermal stresses occurring during shrink-fitting procedure to assemble bascule bridge fulcrums, stresses in human nates when seated in a chair and a patent pending composite body armor, which is significantly lighter than the current body armor and provides much better protection flexibility. Sri received his MS degree in Mechanical Engineering from USF. During his master’s degree, Sri completed a design of experiments study on nano-indentation of fiber-reinforced composite with nonhomogeneous interphase. Sri also worked in developing course modules for “Math for College”, an award winning open courseware for numerical methods for college students and Co-authored textbook chapters “Parabolic Partial Differentiation Equations” and “Elliptic Partial Differential Equations” in “Numerical Methods with Applications” (ISBN13:  978-0201308600) Textbook. Before coming to United States, Sri received his bachelor’s degree from Acharya Nagarjuna University, India. As an Undergraduate, Sri worked as a student intern in organizations in India such as Hindustan Aeronautics Limited (HAL) and MAXrad SOFTware. His areas of expertise include Finite Element Analysis (FEA), Computer Aided Design (CAD), Computational Mechanics, Experimental Mechanics, Structural Dynamics, Mechanics of Composite Materials, Pressure Vessel Design and ASME Section VIII Division 2 (Design by Analysis).

Amin Asareh, Senior Design Engineer

Amin Asareh is Sr. Design Engineer at Openso. Amin holds a doctoral degree in structural engineering from Missouri University of Science and Technology (Missouri S&T), Rolla emphasizing on structural dynamics and earthquake engineering. His PhD research involved evaluation of the nonlinear dynamic behavior of operational wind turbines considering simultaneous aerodynamic and seismic load interaction. Amin’s research included collaboration with National Renewable Energy Laboratory (NREL) for developing and adding a seismic module to the publicly available program FAST (Fatigue, Aerodynamics, Structures, and Turbulence), and also performing nonlinear analysis using Finite Element Medels to obtain the fragility and probability of failure of operational wind turbine structures in the event of earthquake excitation. Amin received his Masters and Bachelor degree from Khajeh Nassir Toosi University of Technology, Iran. His master’s research was focused on nonlinear dynamic behavior of fixed offshore jacket platforms considering soil-structure interaction. His areas of expertise include Finite Element Analysis (FEA), Computer Aided Design (CAD), Structural Dynamics, Earthquake Engineering, Soil-Structure Interaction (SSI), and Pressure Vessel Design.



We offer services that include Finite Element Analysis (FEA, Computational Fluid Dynamics (CFD), vibration analysis, failure analysis, fatigue analysis, wind/seismic analysis, Fitness For Service (FFS), pressure and heat exchanger design, and re-rates.


Openso Engineering is the worldwide licensee of Nooter Corporation entitled to use, market, and sub-license Nooter Corporation’s proprietary methods, techniques, and know-how for the design, analysis, fabrication and testing of pressure vessels and heat exchangers made from titanium, zirconium, titanium clad (single and double integrity), zirconium clad (single and double integrity), tantalum clad, and quench annealed Hastelloy B-2 with Plywall wraps. Our services also include metallurgy, failure analysis by metallurgy, welding, fabrication, forming, non-destructive examination, heat treatment and testing procedures, as well as investigating fabrication problems.

Openso Engineering recognizes the imperatives of our competitive age – speed, low cost, and high quality – in our engineering and fabrication technology services. Openso Engineering strives to provide the optimum solution that is realistic, resourceful, and cost effective, through our knowledge and insight.

Industries Served

  • Petroleum Refinery
  • Petrochemical Industry
  • Chemical Industry
  • Metal Fabrication
  • Polysilicon Industry
  • Paper and Pulp Industry

Partial Client List

  • Arizona Chemical
  • BP
  • Celanese Ltd.
  • Chattanooga Boiler & Tank
  • Chevron
  • Chicago Bridge & Iron (CB&I)
  • Continental Fabricators Inc.
  • Eastman Chemical
  • Evonik Industries
  • Formosa Chemicals
  • Foster Wheeler
  • GT Advanced Technologies
  • Hantech
  • Hemlock Semiconductor Corp.
  • LyondellBassell
  • INEOS Technologies
  • International Paper
  • Kennedy Tank
  • Marathon Petroleum Company
  • Nooter Construction Company
  • Phillips 66
  • SABIC Innovative Plastics
  • SG Solutions
  • Southern Heat Exchanger Corp.
  • Valero Energy Corporation
  • Watlow Electric