ME’scopeVES (Visual Engineering Series) is a series of software packages designed to make it easier for you to observe and analyze a variety of noise & vibration problems in machinery and structures. ME’scopeVES is used for operating deflection shape (ODS) analysis, modal analysis, acoustic analysis, MIMO modeling & simulation, and structural modifications. ME’scopeVES is used to display and analyze experimental multi-channel time or frequency domain data, acquired during the operation of a machine, or forced vibration of a structure. With it, you can interactively display ODS’s, mode shapes, acoustic shapes, or engineering data shapes directly from experimental data. By animating the spatial response of a structure in slow motion, you can view a structure’s overall motion, and the motion of one part relative to another. Locations of excessive vibration are easily identified. You can also view mode shapes, which give you a better understanding of troublesome resonant vibration problems, so that structural modifications can be made to control or isolate them. With interactive sweep animation, you can animate a structure model by sweeping through a set of time histories, and observe its overall response; whether it be sinusoidal, random, transient, linear or non-linear, stationary or nonstationary. With interactive dwell animation, you can dwell at a specific time or frequency in a set of response data, and display shapes statically or with sinusoidal animation.
Interactive Shape Animation
An Operating Deflection Shape (ODS) is the simplest way to see how a machine or structure moves during its operation; at a specific frequency or moment in time. An ODS contains the overall dynamic response of a structure due to forced and resonant excitation. With sweep animation, Time-Based ODS s are displayed by sweeping through a set of time histories describing motions at multiple points and directions on a test article. You can use sweep animation to analyze the run up, coast down, or other transient behavior of a machine. With dwell animation, you can observe the Frequency- Based ODS of a structure at a single frequency. A frequency-based ODS can also help you determine whether or not a resonance is being excited, or whether the vibration is an order related forced vibration.
Modal analysis is used to analyze resonant vibration in a structure. Modal parameter estimation (or curve fitting) is used to estimate the modal parameters of a structure from a set of FRF data. Each mode is defined by its modal frequency, modal damping, and mode shape. This option includes SDOF (one mode at a time), MDOF (multiple modes at a time), and Global (multiple measurements at a time) curve fitting methods for estimating modal parameters. SDOF curve fitting is fast and easy to use, and is useful for quickly obtaining mode shapes so that they can be displayed in animation. MDOF curve fitting is more powerful, and simultaneously estimates modal parameters for two or more modes at a time. It is useful for curve fitting FRFs with high modal density (many modes in a small frequency band). whether the vibration is an order related forced vibration.The Complex Exponential method curve fits a set of time domain Impulse Response Functions (inverse FFT’s of FRFs) using a least squared error algorithm. The ERA method, developed by NASA for use with large scale modal tests on spacecraft structures, also curve fits a set of IRF data. The Z-Polynomial method uses the Z-transform to significantly enhance the numerical stability of the Polynomial method, thus allowing it to also estimate the parameters of a large number of modes.
For cases where excitation forces cannot be measured and only operating responses can be acquired, modal parameters can be extracted from a set of specially processed Cross Spectra or ODS FRFs. This option adds special windowing and other features to the Multi-Reference Modal Analysis Option, and provides a complete set of capabilities for extracting modal parameters from measurements made in any type of testing environment.
The Structural Dynamics Modification (SDM) algorithm allows you to calculate the effects of structural modifications on the modes of a structure. Structural modifications are modeled using industry standard Finite Elements. The Finite Element library includes springs, masses, and dampers, as well as higher order elements such as rods (with axial stiffness), bars (with axial, shear, and bending stiffness), triangular and quadrilateral plate elements, and solid elements such as tetrahedra, prisms and bricks
With this option, you can construct a Finite Element model of your test structure and solve for its analytical mode shapes. Experimental FEA allows you to investigate a much wider variety of structural modifications than with the SDM method alone. This option includes both a normal mode “band” solver and a complex mode solver that includes modal damping. The normal mode solver can solve for the modes of FE models with up to 20,000 DOFs, and the complex mode solver can solve for the modes of models with up to 2000 DOFs.
Finite Element Analysis (FEA)
This calculates the normal or complex modes of a structure from a finite element model. It contains a library of finite elements which includes springs, masses, dampers, rods, bars, plates, and solid elements. Mode shape expansions are also obtained from an FEA model and experimental data. FEA models can also be imported and exported in several popular FEA file formats, including the NASTRAN format.
FEA Model Updating
FEA model updating finds the 10 Best solutions that update properties of an FEA model so that its modes more closely match a set of experimental modes. Property changes include mass, spring, and damper changes, rod element cross sectional area, beam element cross sectional area and inertias, plate element thicknesses and material properties (elasticity, Poissons ratio, & density).
The Signal Modules provide the interface to the different signal sources to be measured. A range of individual Signal Modules can be used for signal conditioning of different sensors or data sources. A maximum of 24 channels can be connected to one Signal Module. Visualisation of the input signals is carried out by means of a display and overload LED’s. The display ensures the identificatin of the module within a decentralised configuration by displaying the selected unique module number.
The Signal Module performs the signal conditioning and the A/D conversion (24bit). Each channel is completely independent and consists of sensor support (power), amplifier, A/D converter, anti aliasing filter and optional high or low pass filter. In view of accuracy, measurement speed, and noise characteristic the Signal Modules represent “State-of-the-art” technology. The digital and the analogue module parts and the power voltage input part are galvanic isolated to remove the noise introduced by potential differences. All modules have their own power supplies as well as their own calibration units. The low power consumption of a Signal Module and the enhanced cooling technology avoids the integration of fans in the Signal module which is a big advantage especially for acoustic measurements.
The sample rate can be set for each module individually. A special 6 channel module feature is the overload detection. An overload situation will be detected by means of a comparator already before the A/D conversion. Also one channel can be used as signal channel or a RPM channel. One Signal Module can be connected directly to the USB interface of a PC.