Experimental strain analysis, structural health monitoring and non-destructive testing and evaluation are regarded as separate disciplines that, in general, are deployed independently at different phases in the life cycle of an engineering component, i.e. in the design process, in service and after an event or service period, respectively. It is proposed that the integrated use of these three disciplines is advantageous and beneficial in terms of reduced capital and operational costs for critical and safety-relevant components, as well as, in validating simulations, in both quantifying and reducing risk of unexpected failure, and in estimating remanent life. We propose the foundation of this integration to be data-rich strain fields measured and compared quantitatively, with each other and with data from simulations, at temporal intervals during the life of a component.

A reference material is defined as material, sufficiently homogeneous and stable with respect to one or more specified properties, which has been established to be fit for its intended use in a measurement process. Reference materials provide a simple definition of the measured quantity that can be traced to an international standard and can be used to assess the uncertainty associated with a measurement system. Previous work established a reference material and procedure for calibrating full-field optical systems suitable for measuring static, in-plane strain distributions. Efforts are now underway to extend this work to the calibration of systems capable of measuring three-dimensional deformation fields induced by dynamic loading. The important attributes for a dynamic reference material have been identified in a systematic and rational fashion, which have been subsequently translated into a generic design specification. Initial prototypes of candidate designs have been produced and evaluated using experimental modal analysis and digital speckle interferometry, and the results have been compared with finite element analyses. Based on the outcome of this initial evaluation, further refinements in design and manufacturing are proposed.

Innovative designs of transport vehicles need to be validated in order to demonstrate reliability and provide confidence. The most common approaches to such designs involve simulations based on Finite Element (FE) analysis, used to study the mechanical response of the structural elements during critical events. These simulations need reliable validation techniques, especially if anisotropic materials, such as fibre reinforced polymers, or complex designs, such as automotive components are considered. It is normal practice to assess the accuracy of numerical results by comparing the predicted values to corresponding experimental data. In this frame, the use of whole field optical techniques has been proven successful in the validation of deformation, strain, or vibration modes [1]. The strength of full-field optical techniques is that the whole displacement field can be visualized and analyzed. By using High Speed cameras, the Digital Image Correlation (DIC) method can be applied to highly non-linear dynamic events and deliver quantitative information about the three-dimensional displacement field [2].

Flaw and damage assessment in torsionally loaded CFRP cylinders using experimental and numerical methods, Composite Structures (2015), doi: http://dx.doi.org/10. 1016/j.compstruct.2015.05.025 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. AbstractCFRP structural elements are prone to failure initiating from defects. While defects are expected after damage has occurred, flaws and voids can already be present after manufacturing. To study the criticality of such defects CFRP cylinders have been manufactured from a lay-up that was designed to predict damage mode and to allow for controlled damage growth under torsional load. FEA simulations of defect-free and flawed cylinder models were performed to first ply / interface failure. X-ray Computed Tomography revealed that cylinders manufactured with different finishing had a completely different void content and distribution. Simulations of failure, using finite element models, for the two classes of void distribution are corroborated by experimental results for the ultimate load, and damage initiation from manufacturing flaws is confirmed. Digital Speckle Pattern Interferometry was used to identify flaws using thermal and mechanical loading, while infrared thermography and thermoelastic stress analysis were used to identify possible failure initiation sites and monitor the failure process and damage growth, whilst the specimen was loaded in torsion.

In this work laser Doppler vibrometry has been used for damage detection in frescoes. Results were compared with the ones obtained through infrared thermography, and, for both techniques, mathematical models were implemented to simulate the physical domains and conditions of the employed test sample. The limitations of each methodology are also discussed. The numerical model of the vibrometric investigations has been constructed using Finite Elements Method modeling. A new procedure based on the observation of Rayleigh waves propagation velocities allowed to acquire sample mechanical parameters. Comparison of experimental and simulated data and independent defect diameter measurement by echographic equipment, allowed to establish the confidence level and the discrepancies in the developed model. Also operational limits of the vibrometric technique have been studied by acquisition of Signal-to-Noise ratio on different areas of a sample. The Fourier equation has been used for the mathematical model employed for the numerical simulation of the thermographic investigations. Numerical technique with formularization in finite volumes has been employed and a FORTRAN ® code has been developed to solve the thermal problem.