Vibration & Dynamic Analysis
At best, unwanted vibration can cause discomfort to a vehicle passenger or system operator. At worst, vibration can cause catastrophic failure. Abnormal levels of vibration and noise in a structure are often the first indicators of an internal problem or damage, and identifying the cause early can allow intervention before total system failure leads to expensive repairs, disruption of operations, loss of revenue, or injury.
Dynamic or vibrational considerations are often overlooked during design, resulting in vibration as a common failure mode across a wide range of products and applications. Vibration resonance can be particularly destructive when it involves large displacements that can result in high structural stresses. Vibration induced fatigue is also a common failure mode of machinery, but can be avoided through robust design of the vibrating part, or avoiding resonant frequencies during operation.
Exponent’s vibration specialists can locate possible causes of vibration in existing systems, and identify methods to mitigate excessive vibrations through comprehensive analysis and testing. Our staff has expertise in evaluating a wide variety of vibration-related applications, including:
- Providing front-end design guidance to prevent vibration issues
- Measuring system vibrations for diagnostic purposes, and
- Evaluating vibration as a root cause of failure.
Exponent’s Vibration Analysis Services:
Exponent’s expertise in the field of vibration analysis spans a range of industries including consumer products, railways and vehicles, space, and structural applications. Our team of scientists, engineers, and technicians can investigate all matters or objectives in the field or in the lab, from component level to system level and from nanoscale systems to skyscrapers.
From hand-held end-user testing to industrial sized turbines, Exponent has solved problems on a variety of projects requiring the measurement, diagnosis, and analysis of system and structure vibrations. We have experience with rotating machinery vibration and turbine vibrations, including diagnostics and sensor application as well as root cause failure analysis. Exponent can analyze the dynamic response of structures using computer based numerical analysis (including nonlinear finite element analysis) and provide measurements of actual vibration conditions using both contact and non-contact measurement options. Common objectives include minimizing vibrations transmitted from a system to the surrounding environment (e.g., vibrations associated with drilling or construction operations), or conversely, isolating a system from vibrations in the surrounding environment (e.g., vehicles traveling on rough terrain or the protection of sensitive electronic equipment). In other cases, the objective is to control, maximize, or optimize system vibrations (e.g., atomic force microscopes or vibrating screens used in raw material processing or drilling operations).
- Shock and vibration testing
- Design of experiments (DOE) and selection of appropriate sensing technologies
- Planning and implementation of dynamic testing to be conducted by client
- Identification of damping mechanisms
- Modal testing and analysis; determination of system parameters, resonant frequencies, mode shapes, and amplitude response
- Health monitoring testing of vibrating equipment
- Human whole body vibrations and hand-arm vibrations (ISO 2631, ISO 8041)
- Seismic monitoring of ground and structural responses
- Vibration sensitivity; de
- termination of allowable vibration levels
- Evaluation of sound (OSHA compliance) and vibration levels in machinery and building structures
- Non-contact measurement
- Dynamic modeling and simulation, including development of customized dynamic solvers
- Dynamic finite element analysis of free
- and forced vibration (including ASTM and MIL SPEC vibration tests), shock analysis, and component drop analysis
- Evaluation of vibration isolators and damping techniques
- Development of threshold vibration levels for products
- Evaluation of existing product design for vibration considerations and specifications
- Product redesign or corrective actions for vibration mitigation
- Human vibration dosage (VDV, MTVV, 8th octave, etc.)
- Acoustic analysis and human perception
- Analysis of flow-induced and acoustic-induced vibration (FIV/AIV)
- Coupled finite element/fracture mechanics analyses to predict crack growth rates due to random vibration profiles
Exponent’s expertise in a wide range of engineering disciplines can be leveraged to complement our dynamic analysis in order to assist clients in addressing complex business and legal issues. We can conduct vibration analyses in the context of the larger picture, considering other possible failure modes or design considerations. For example, one case study involved failures resulting from a combination of static design flaws as well as increased loading due to resonance vibration. Neither of these issues alone was enough to cause failure, but Exponent’s approach of analyzing vibration in addition to other engineering considerations confirmed a high failure rate was due to the combined effects.