Minimal Invasive Diagnostic Capabilities and Effectiveness of CFRP-Patches Repairs in Long-Term Operated Metals

Abstract

The paper deals with the subject of diagnostics and the quick repairs of long-term operated metallic materials. Special attention was paid to historical materials, where the structure (e.g., puddle iron) is different from modern structural steels. In such materials, the processes of microstructural degradation occur as a result of several decades of exposure, which could overpass 100 years. In some cases, their intensity can be potentially catastrophic. For this reason, the search for minimally invasive diagnostic methods is ongoing. In this paper, corrosion and fracture toughness tests were conducted, and the results of these studies were presented for two material states: post-operated and normalized (as a state “restoring” virgin state). Moreover, through the use of modern numerical methods, composite crack-resistant patches have been designed to reduce the stress intensity factors under cyclic loads. As a result, fatigue lifetime was extended (propagation phase) by more than 300%.

Analysis of the Deceleration Methods of Fatigue Crack Growth Rates under Mode I Loading Type in Pearlitic Rail Steel

“…For the experimental campaign, compact tension (CT) specimens were prepared in accordance with ASTM E647 [25] standard. The scheme of the specimen is shown in Figure 2.…”

“…For specimens without CFRP stress intensity factor was calculated based on linear elastic fracture mechanics [25]:…”

Advances in Design by Metallic Materials: Synthesis, Characterization, Simulation and Applications

“…The collection includes papers regarding the most multifaced aspects of metals as synthesis [1][2][3], treatments [2][3][4], experimental characterization [4][5][6][7], material models [7][8][9] and engineering applications [10][11][12] providing a clear cross-section of the wide variety of topics and research arguments under investigation in the scientific community now.…”

“…Numerical models, sometimes powered by finite elements, are also present in other contributions with the scope to predict plasticity [9] or failures [10] or, even, to support design actions with the scope to optimize the use of metal structures [11]. Finally, the last paper in the list [12] is maybe able to provide a synthesis in the proposed concept, regarding the opportunity of metallic materials, often considered as belonging to a quite old past, in an epoch where a large assortment of new materials is emerging, as in the case of polymer composites. This paper, not even doing it on purpose, deals with an intrinsic connection that our near future could bring out, merging two worlds only apparently strangers, when it proposes to use composite patches to repair metal bridges in order to extend their life for the benefit of society, not replace them.…”

Optimization Analysis Method of New Orthotropic Steel Deck Based on Backpropagation Neural Network‐Simulated Annealing Algorithm

“…However, in the long-term service, fatigue cracking problems are present in many orthotropic steel bridge decks (OBDs). According to the statistics, fatigue almost accounts for 80%-90% of metallic failure [4][5][6]. Fatigue cracks occur for a variety of reasons, but there are three major reasons.…”