1,721,064 research outputs found
Predicting the frequency response function of a structure when adding constraints
No full textA method is developed to predict the dynamic behavior of a structure from experimental FRF data of the same system subjected to different constraints. In particular it is required that the new structure undergoes more restrained conditions, but any type of ideal constraint, involving either translational or rotational degrees of freedom, can be accounted for. Among several interesting applications, the method can be used to overcome typical experimental drawbacks on rigid tested structures and to estimate untestable FRF terms of constrained systems. Numerical and experimental results are provided to show the consistency of the method and the possible range of applications
Solution of quasi-harmonic equations through the combined finite element-transfer matrix method
No full textThe technique of finite element transfer matrix method in the study of steady and transient heat conduction problems
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Bias in modal parameters using the direct and iterative RFP identification procedures
No full textIn the rational fraction polynomial method [1] the identification of modal parameters is obtained through a direct linear least-square optimization technique but a particular form of fitting error is minimized. An iterative algorithm has been recently developed which uses the true fitting error [2]. In this paper a statistical analysis is developed to estimate the bias effects on the identified parameters when the data are polluted with noise. Both the direct and iterative procedures are considered. Numerical simulations are used to validate the results predicted by the theoretical analysis, which shows that the iterative approach is by far more efficient than the direct method. © 1995 Kluwer Academic Publishers
A unified approach to substructuring and structural modification problems
No full textSubstructures coupling is still an important tool in several applications of modal analysis, especially structural modification and structures assembling. The subject is particularly relevant in virtual prototyping of complex systems and responds to actual industrial needs. This paper analyzes the possibility of assembling together different substructures' models. The important role of rotational DoFs is highlighted, underlying the difficulty of assembling theoretical and experimental models, for which, usually, the rotational DoFs are not available. Expansion techniques can be used to provide this information as well as appropriate modelling of joints. With this information, FRF models, modal models and FE models can be appropriately combined together and solutions for several cases of practical interest are presented. The analyzed procedures are tested on purpose-built benchmarks, showing limits and capabilities of each of them
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