Overview
ISO 7626-2:2015 - part of the ISO 7626 series on mechanical vibration and shock - defines standardized procedures for experimental determination of mechanical mobility using a single-point translational vibration exciter attached to the test structure. The standard covers measurement of related frequency‑response functions (mobility, accelerance, dynamic compliance) as driving‑point or transfer measurements. Although excitation is applied at one location, simultaneous motion measurements at multiple points are supported, making the method suitable for modal analysis and multi-point dynamic characterization.
Key topics and technical requirements
- Measurement configuration: overall test-system layout, support of the structure (grounded vs ungrounded), and exciter attachment.
- Excitation methods: permitted waveforms (discretely dwelled sinusoidal, slowly swept sine, stationary random, and others) and control of excitation levels and duration.
- Vibration exciters: selection, attachment, and requirements to minimize spurious forces and moments (including transducer mass and rotational inertia effects).
- Transducer and force measurement: placement and attachment of accelerometers/velocity sensors and force transducers; procedures for mass loading and cancellation.
- Signal acquisition and processing: determination of frequency‑response functions, filtering, frequency resolution and avoidance of saturation for both sinusoidal and random excitation.
- Calibration and validation: operational calibration of sensors and amplifiers, tests for valid data (normative annex), and criteria for reliable measurements.
- Modal parameter identification: guidance (informative annex) on extracting modal properties (natural frequencies, damping ratios, mode shapes) from multiple-response mobility data.
- Supporting annexes: normative tests for validity and requirements for excitation frequency increments/durations.
Applications and users
ISO 7626-2:2015 is intended for engineers and laboratories involved in:
- Vibration testing and structural dynamics of buildings, machines, vehicles and other assemblies.
- Modal analysis, model validation and updating of finite-element models using measured mobility or accelerance data.
- Predicting dynamic interaction between interconnected components and assessing vibration transmission.
- Material dynamic property estimation and troubleshooting vibration problems in design and manufacturing.
Typical users: vibration test engineers, NVH (noise‑vibration‑harshness) specialists, structural dynamics researchers, test-house personnel and consultants.
Related standards
- ISO 7626-1 - Basic terms, definitions and transducer specifications (refer to for definitions and limitations).
- ISO 7626-5 - Measurements using impact excitation (alternative excitation method).
- ISO/TC 108 - Technical committee on mechanical vibration, shock and condition monitoring.
Keywords: ISO 7626-2:2015, mechanical mobility, vibration testing, single-point translation excitation, vibration exciter, frequency-response functions, accelerance, dynamic compliance, modal analysis.