Composite materials are vulnerable to impacts that may occur during their use. Such transverse loads represent a significant threat to these materials because they can cause damage that is difficult to detect. Thus, understanding the mechanical behavior of composite materials during impacts is crucial for improving their damage resistance. Therefore, this study investigates the response of two commonly used composite panels in maritime transportation—a PVC core sandwich composite and a laminated GFRP composite—under quasi-static indentation (QSI). Using numerical simulations with Abaqus/Explicit, this investigation aims to anticipate mechanical characteristics and damage patterns during low-velocity impact. Results show a strong correlation between numerical and experimental data. The force-displacement curves aid in understanding damage sequences, with predicted maximum loads at 1.43% and 6.45% accuracy for laminated and sandwich composites. Both exhibit significant damage, including permanent indentation, matrix cracks, fiber fractures, and prevalent delamination around the impact point.

Fused filament manufacturing (FFF), also known as 3D printing, is one of the most commonly used additive manufacturing techniques for creating high-quality materials. This process demonstrates the intricacies and challenges involved in choosing appropriate manufacturing parameters to achieve the desired outcomes. Among these critical parameters is the nozzle temperature, which can be adjusted to enhance the mechanical properties of the 3D-printed Polyphenylene Sulfide (PPS) parts. The main objective of this study is to investigate the influence of the printing temperature on the mechanical properties and failure characteristics of 3D printed polyphenylene sulfide (PPS) parts during impact testing. To do this, a series of simple and repeated impact tests were carried out on printed PPS samples in the nozzle temperature range (320–350 °C). CHARPY tests were carried out on the samples manufactured with different sequences for the optimal orientation of the filaments. Furthermore, the impact energy absorption capacity and the induced damage as a function of nozzle temperature were evaluated. CHARPY test results showed that samples with stacking sequence (0/0) had the best impact resistance and specific absorbed energy (SEA). This sequence, printed horizontally, was used to test different print temperatures in single and repeated impact tests. Furthermore, the results indicated that samples printed with a nozzle temperature of 340 °C exhibited higher CHARPY impact resistance and specific absorbed energy (SEA), with a percentage difference of 45.57%, 41.95% and 44.21% compared to samples printed with nozzle temperatures of 320 °C, 330 °C and 350 °C respectively. For repeated impact tests, the results also show that samples printed with a nozzle temperature of 340 °C have a higher initial energy absorption rate and a greater number of impacts before complete failure of the sample. This result proves also that the changing of nozzle temperature does not have a significant effect on the induced damage after CHARPY and repeated impact.

Failure of 90° elbows in water pipes due to corrosion is a critical issue in water supply and distribution systems. Therefore, understanding the behavior of pipelines under corrosion is essential to increase their durability. This original study aims to specifically analyze the failure of 90° elbows due to the erosion-corrosion phenomenon. The behavior of water flow, in terms of velocity profile, pressure gradient, and turbulence zones at these elbows, is numerically simulated using the computational fluid dynamics (CFD) method. The simulations, performed with FLUENT software, identify the areas most susceptible to erosion and corrosion, thus contributing to a better understanding of processes such as stress corrosion cracking and cavitation. This work also highlights the importance of designing elbows with suitable characteristics and adopting adequate maintenance practices to prevent failures. These results can serve as a basis for future experimental validations and for the design of more robust pipeline systems.

Composite materials are categorized to be highly sensitive to low-velocity impact events. This feature is considered as a serious limitation for their application in engineering. Therefore, understanding impact energy absorption is critical in improving composite material damage tolerance and especially under successive impacts. This work was dedicated to an experimental investigation that aims to study and compare the energy absorption ability and damage behavior of PVC-foam sandwich and GFRP laminated composites under multiple impacts occurring at small energy levels. For this purpose, low-velocity impact repeated tests were carried out until total absorption of the impact initial energy was reached. A relative energy absorption index and a rebound index were proposed in order to assess energy absorption capacity. The results indicated that, directly after the first impact, the sandwich composite formed from two 4mm laminated skins absorbed 80% of the initial impact energy, in comparison to approximately 60% for 8mm laminated composite. This performance of sandwich composite is attributed to the damping ability of the core. Also, the impact velocity rebound rate of this composite was found to be higher than that of laminates. However, impact damage is greater in composite sandwiches than in laminates.