VDN Newsletter 2016-1 - July 2016

1  Vibration, dynamics & noise - a new service line

By Russ Barss, Director, vibration, dynamics & noise services

An exciting year for our team...
Wood Group logo
One of Wood Group's strategic initiatives was to build the world's leading capability in the area of vibration, dynamics and noise. In less than 12 months, this vision became a reality with the acquisition of BETA Machinery Analysis and SVT Engineering Consultants (Australia), coupled with the creation of our advanced engineering team in the UK.

These three organizations now work closely together as the vibration, dynamics & noise (VDN) service line. With more than 230 engineering specialists in 11 offices around the world, our VDN service line is a truly global operation with an industry-leading position based on its niche range of services, software solutions, industry research and technical authorities. 

VDN forms part of Wood Group’s overall asset integrity solutions offering which expands to include all-of-facility integrity management, maintenance solutions and inspection services. 

Wood Group’s capabilities in asset integrity have expanded with a strengthened VDN service line which brings together three complementary businesses: 


2  Acoustic-induced vibration (AIV): latest API 521 standard and new requirements for operators

​​​By Jonathan Baker, Principal Consultant, vibration, dynamics & noise services

AIV piping failure

The consequences of a piping failure can be costly and potentially even deadly. Failures due to AIV have had a significant operational and economic impact for operators, especially on newly commissioned facilities. As a result, AIV has recently been added to API 521 as a design requirement for gas relief systems at compressor stations, refineries, gas plants, offshore platforms and LNG facilities. This article explains the phenomenon of AIV, API 521 approaches and improved methods based on Wood Group’s industry research and field work.


3  DamperX piping vibration solutions

DamperX anti-vibration clamps reviewDamping is a proven solution to control vibration, and is used extensively in the automotive and aerospace industries (think of the shocks in your car).

Wood Group has applied this technology to industrial applications involving piping, compressors, pumps and related equipment. This new solution provides a cost-effective approach to absorb vibration energy and reduce stress, thereby preventing fatigue failures.

Our DamperX™ anti-vibration products have a proven track record of significantly reducing vibration compared to standard steel and other lined clamps and supports. Read more 

4  Subsea vibration - how to assess and avoid fatigue failure risks

Existing guidance on vibration in piping systems is aimed at topsides and onshore piping systems. Given the unique challenges with subsea systems, the need for separate guidance was identified. Development of this new subsea guideline was commissioned by the Energy Institute (EI)


  • Identify good design practice and hence ensure a robust design
  • Extend screening methodologies to include additional excitation mechanisms, and reduce conservatism in certain methods
  • Provide additional guidance on detailed fatigue assessment approaches
  • Provide guidance on subsea vibration monitoring methods, and the use of monitoring data 

The key steps in the assessment process are shown below:

Subsea Piping Vibration – Overall Approach

The new document is in final draft and expected to be published soon. The steering committee includes representatives from a number of operators including Shell, BP, Total and Chevron. The VDN service line is currently performing an assessment for a subsea tie-back to an existing installation. 
Read more about subsea piping vibration

5  Centrifugal compressor surge - free online assessment tool

Centrifugal Compressor
This free calculation tool can determine your compressor application's risk of surge. It provides a quantitative score using the non-dimensional inertia number to determine the optimal level of surge analysis given the compressor's proclivity to surge. Try the free calculator

6  Research update on joint industry projects (JIPs)

AIV FEA model

Acoustic-induced vibration (AIV) JIP


Wood Group is participating in an Energy Institute joint industry project (JIP) addressing  AIV. The current phase seeks to provide measurement data to give insights as to the response of different piping configurations to AIV, and quantify the effectiveness of various mitigation measures.

Test work is being undertaken at the Emerson Fisher flow labs in Marshalltown under high-pressure relief and blowdown conditions. Wood Group is providing data analysis capability of the acquired dynamic strain, acceleration and dynamic pressure data as part of our in-kind contribution to this applied research program.
BP, Chevron, ConocoPhillips and Nexen are the principal operating companies involved, with other contributors including Bechtel, Chiyoda, Emerson Process Management, KBR, Petrofac and Xodus. Read more 
SLARP JIP testing setup

Slug loading & response in pipelines and risers (SLARP) JIP

Wood Group is also managing a SLARP JIP, which deals with the development of methods for the design and analysis of slug loading and response in subsea pipelines, risers, jumpers and free-spans.

The JIP is structured around three key aspects:
  1. Development of global numerical analysis models for the prediction of pipeline and riser structural dynamic response to slug flow
  2. Full-scale model testing and global finite element analysis correlation
  3. Development of an industry design guideline reflecting best practice design and analysis techniques for determining structural response to slug flow
Participants currently include BP, Chevron, Total and Saipem. Read more

7  Upcoming events - vibration training and conferences

Sept 12-15 Turbomachinery & Pump Symposia  Visit us at booth 2134!
Tutorial: "Reciprocating Pump Design Considerations Unlike Centrifugals"
Houston, Texas
Sept 14-15 European Forum for Reciprocating Compressors
Paper: "Vibration Assurance of Vertical Scrubbers for Reciprocating Compressor Packages"
Düsseldorf, Germany
Sept 26-30 International Pipeline Conference
Paper: "AIV and FIV in Pipelines, Plants, and Facilities
Calgary, Canada
Oct 2-5 GMRC Gas Machinery Conference  Visit us at booth 610!
Three papers:
- "Improved Method of Calculating Power Loss in Reciprocating Compressor Installations"
- "Damping Components at a Reciprocating Compressor Station"
- "Vibration-Induced Fatigue Failure Assessment of Discharge Bottle Fitting Connections"

Three short courses:
- "Real-World Solutions For Old-World Vibration Problems
- "Station Dynamics for Centrifugal Compressors
"Control of Torsional Vibrations in Direct‐Driven Separable Reciprocating Compressors Vibration"

New technology update:
"Introduction of DamperX Anti-Vibration Clamps"

Denver, Colorado
Technical training The VDN service line provides a variety of customer training sessions.
See our website for the most common courses, or contact us for customized training programs.
We also have a number of training videos, technical articles and calculation tools available for free in our Knowledge Center.