Xdot Rotordynamic Analysis Consulting Services

Xdot’s rotordynamics analysis consulting services help ensure that your machines will run smoothly and support a valuable return on your investment. 

We have conducted analyses on machines and machinery trains ranging from a 1200 MW nuclear steam turbine train with a rotating assembly weight of over 1.25 million pounds, down to rotors weighing less than a pound. We use a combination of in-house analysis tools, along with DyrobesⓇ, to quickly and accurately perform all of the “standard” analyses along with other techniques unique to Xdot’s analysis approach.  

Xdot delivers independent rotordynamics analysis. These detailed design review steps help our clients maximize the chances for success of the machine first build and shorten the development cycle. Some project examples include:

• Rotordynamics design reviews and audits, using American Petroleum Industry standards, for a new machine or significant upgrades
• Evaluation for pumps (Brown and Caldwell, and other standards), mixers, as well as to Xdot’s requirements when no industry standard applied

The Xdot team firmly believes that successful development of new technology requires a robust effort that combines analytical  work with guidance from hardware testing and verification. Xdot has extensive experience designing and building bearing test rigs, going back to multiple bearing test rigs Xdot’s founder, Dr. Swanson, developed while in graduate school in the 1990s. 

For our clients developing new product lines which depend on foil bearing technology, it is important that they have their own in-house foil bearing expertise to carry them through the product development and support life cycle. Xdot’s development and production of high speed test rigs, especially for foil bearings, supports this integral part of a client’s successful project outcome. In several cases, we have developed, produced, and delivered new test rigs tailored to clients’ specific product needs to allow clients to perform their own testing.

Most of Xdot’s foil bearing machine development efforts for clients begins with a feasibility study. This study is performed as a risk reduction step to ensure that a proposed foil bearing support machine has a reasonable chance of running. This study generally includes:

• Radial and thrust foil bearing sizing and preliminary selection of design details based on operating speed, loads, and other performance requirements and constraints (e.g., operating fluid, pressure, temperature)
• Review of rotordynamics performance of the design concept
• Review of how foil bearings will be integrated into the design
• Identification of any items of concern from the foil bearing and rotordynamics perspectives

We complete the design review with a go/no-go recommendation. If the risk looks reasonable, we develop a roadmap for next steps. Where possible, we try to leverage existing and proven bearing designs. As much as we advocate foil bearings, there are applications that won’t work, or where the balance of development risk versus reward is not acceptable. In these cases, we draw upon our years of machinery audit and analysis experience to identify a solution that will work at a lower risk.

While Xdot does not typically do field vibration troubleshooting and data collection, we excel at providing rotordynamics analysis consulting support to clients and or their subcontractor teams who are trying to solve field problems.

Often the only way to make headway with a really difficult machinery vibration problem is to create a rotordynamics model, tune and validate it using field data, and then use the model to understand why the machine is vibrating. Once the “why” is understood, a rotordynamics analysis can guide development of solutions and predict whether the solutions will work. When successful, hard problems can sometimes be solved the first time, rather than through costly trial and error. 

Foil bearing machines have some unique characteristics. Xdot’s deep understanding of foil bearings and years of practical experience allows us to help diagnose and deal with problems too challenging for a non-foil bearing expert. We have helped multiple clients who were developing foil bearing machinery resolve problems they were unable to solve on their own. We have looked at bump foil bearings, overlapped leaf bearings, and even flexed-tab designs. If you are struggling with foil bearings, we want to help you succeed even if we are not the foil bearing product supplier.