Structural Analysis Using Finite Element Analysis (FEA)

Detailed three-dimensional (3-D) finite element models are often used to evaluate mechanical natural frequencies and/or static stress of structures, vessels, skids, etc. EDI is equipped with cutting edge CAD and FEA software (Inventor and ANSYS) and has the experience to create and analyze sophisticated finite element models. With today’s technology, detailed 3-D FEA models are practical, and have more accuracy over traditional analysis methods.

FEA is useful for failure analysis as well as design audits. The load conditions on a failed part can be modeled to determine if a mechanical resonance or static overload is responsible. These analyses can be combined with metallurgical examination to develop a complete picture of the conditions leading to the failure. Identification of failure modes leads to successful redesign of the component.

In addition to weight loading, a structure must be designed to withstand external loading from machinery live loads, and the environment. Cyclic loading can be more detrimental to a structure than a static or weight load. The dynamic characteristics of structures must be tailored to the equipment installed on them. A structure must not have natural frequencies or mode shapes which could be excited by the harmonic forces from operating equipment. A complete analysis of the structure and the supported equipment can be performed to “de-tune” the structure and avoid resonant conditions.

Example: Compressor Manifold Vibration

An important aspect of the mechanical design of a reciprocating compressor system is the structural dynamic response of the compressor manifold system. The compressor manifold system typically includes the crosshead guide(s), distance piece(s), cylinder(s), suction and discharge bottle(s), and attached piping to the first clamp or appropriate boundary condition. There are many different system configurations. For this reason, a significant amount of engineering effort is devoted to coordinating the mechanical design of compressor manifold systems with the pulsation analysis.