The use of composite materials is ubiquitous in every field of human activities, including in the agricultural, industrial, environmental, biomedical and transport sectors. After a pandemic with the ...simultaneous unfolding of an energy and climatic crisis, we now realize how necessary it is to carry out studies on composite materials based on polymers to positively affect our current society and, in particular, future generations.To this aim, in the present selection of scientific articles we have given visibility to worthy contributions on a wide variety of topics, highlighting how essential plastic-based composite materials and their derivatives are in our daily lives. The articles in this Special Issue were wide-ranging and devoted to the properties and characterization of composites for innovative and strategic applications and, more generally, for the development of the chemical–physical properties of these materials.
This paper reports a study of the initiation of the first failure event in unidirectional composites subjected to transverse tension. Two energy based point failure criteria – critical dilatational ...energy density and critical distortional energy density – are considered. The manufacturing induced disorder in the fiber distribution in the composite cross section is described in terms of the degree of nonuniformity, which is quantified and for which an algorithm is developed. The nonuniformity is captured in a representative volume element (RVE) whose minimum size is determined based on statistics of nearest fiber distance distribution. Several realizations of the RVE for three fiber volume fractions and three degrees of nonuniformity are analyzed using a finite element model. A parametric study of the effect of matrix/fiber stiffness ratio on the damage initiation is also conducted. Significant effects of the fiber distribution nonuniformity on the strain to onset of damage are found.
Objectives
This study evaluated the clinical performance of bulk‐fill resin composite systems with different viscosities in class II cavities.
Materials and Methods
A total of 80 class II ...restorations were performed with a single operator in 50 patients using four different bulk‐fill resin composite materials: Filtek™ Bulk Fill, Heated Filtek™ Bulk Fill, G‐ænial™ BULK Injectable, and SonicFill3. A double‐blinded randomized clinical trial was designed to evaluate the two‐year clinical performance of the four bulk‐fill composite resins using modified FDI criteria.
Data were analyzed descriptively. Level of significance was set at 0.05. Differences between groups were tested using Wilcoxon‐signed‐rank and Mann–Whitney‐U test as nonparametric tests.
Results
Data were analyzed using Kruskal‐Wallis, Mann–Whitney U, and Wilcoxon signed rank tests (p < 0.05). Eighty restorations were available for evaluation, with a survival function of 100%. No statistically significant differences were observed between the four groups regarding assessing esthetic, functional, and biological properties during different follow‐up periods.
Conclusions
After 2 years of clinical follow‐up, the bulk‐fill composite systems with different viscosities seem to be esthetically, functionally, and biologically acceptable, with a promising clinical performance in class II cavities.
In recent times, the utilisation of marine composites in tubular structures has grown in popularity. These applications include composite risers and related SURF (subsea umbilicals, risers and ...flowlines) units. The composite industry has evolved in the development of advanced composites, such as thermoplastic composite pipes (TCP) and hybrid composite structures. However, there are gaps in the understanding of its performance in composite risers, hence the need for this review on the design, hydrodynamics and mechanics of composite risers. The review covers both the structure of the composite production riser (CPR) and its end-fittings for offshore marine applications. It also reviews the mechanical behaviour of composite risers, their microstructure and strength/stress profiles. In principle, designers now have a greater grasp of composite materials. It was concluded that composites differ from standard materials such as steel. Basically, composites have weight savings and a comparative stiffness-to-strength ratio, which are advantageous in marine composites. Also, the offshore sector has grown in response to newer innovations in composite structures such as composite risers, thereby providing new cost-effective techniques. This comprehensive review shows the necessity of optimising existing designs of composite risers. Conclusions drawn portray issues facing composite riser research. Recommendations were made to encourage composite riser developments, including elaboration of necessary standards and specifications.
This reprint summarizes recent advances in the production and research of biobased and biodegradable polymeric composites for various applications. The development and characterization of ...environmentally friendly, conductive and biomedical materials as well as materials with barrier and antimicrobial properties have been considered and discussed.
In the last decade, design and material innovations for manufacturing composites have reached new heights. Thermoplastic polymers and their composites have become the most in-demand materials in ...recent times as they provide numerous advantages over thermoset composites. Thermoplastic polymers have a high damage tolerance, high impact resistance, recyclability, formability, weldability, repairability, and cost-effectiveness compared with thermoset composites. Thermoplastic polymers and composites are widely used in automotive, aerospace, electrical and electronics, industrial, and medical applications. Thermoplastic composites are estimated to grow from USD 28.0 billion in 2019 to USD 36.0 billion by 2024. High-performance thermoplastic materials are used in conjunction with a multitude of manufacturing processes like injection moulding, thermoforming, prepreg, liquid injection processes, automated tape placement, filament winding, pultrusion, additive manufacturing, and other processes. The material limits, design, and assembly requirements, as well as the processing constraints, are significantly important for the realisation of novel product development using a manufacturing process by simultaneously optimising reliability, safety, and other performance-related issues. The current thermoplastic material systems and manufacturing techniques still have plenty of room for optimisation and advancement. This reprint presents the latest scientific and technical advances in thermoplastic materials and their composites, processing, characterisation, product development, and manufacturing process parameter optimisations.
The present work aims to investigate the relationship between the mechanical behavior and composite structure of silicon carbide (SiC) particle reinforced aluminum matrix composites. On account of ...newly developed particle size analysis technique, a large number of SiC particles are experimentally measured to provide statistical particular structural information. According to the statistical analysis and physical observations of SiC particles, the composite structures of SiC/Al composites are numerically reproduced in line with their actual microscopic structures, in which a developed structural modeling program can build the randomly dispersions of the particle sizes, the particle shapes, the particle positions and the volume fractions of SiC particles. Elastoplastic material properties, strengthened matrix properties and particle–matrix interfacial behaviors are introduced to simulate the mechanical behavior of SiC/Al composites. Enough fine meshes and reasonable loads and boundaries conditions can efficiently guarantee the computing accuracy and reduce the computing cost. A lot of simulating results of SiC/Al composites are provided and verified with the related experimental results. This work makes an effective attempt to establish the relationship between the actual composite structures and the mechanical behaviors within the particle reinforced metal matrix composites.
Fiberglass reinforced composites (FRCs) are traditionally cured in an autoclave or hot press, which are equipment known for their high energy consumption and their imposed constraints on the cured ...component sizes. Furthermore, current composite repair techniques usually require removing the composite part from service and using traditional composite fabrication methods to apply patches in a workshop. As an alternative to such techniques, this work presents a new out-of-autoclave (OoA) FRC curing method that relies on the Joule heating potential of transfer-printed laser induced graphene (LIG) interlayers. LIG is initially generated on polyimide substrates before then being transfer-printed onto fiberglass prepregs to form uniform surface coatings. The excellent electrical properties of the transfer-printed LIG are then exploited to in-situ cure fiberglass laminates via Joule heating effect. The LIG-coated FRCs cured through Joule heating (LIG-cured FRCs) is found to have a high degree of cure of 96%, comparable to oven-cured ones, while requiring 89.39% less specific energy. The mechanical properties of LIG-cured FRCs are measured and determined to match those fabricated using traditional approaches. Furthermore, LIG-coated fiberglass prepregs are shown capable of acting as in-situ bonding agents for the joining of two composites structures, which indicates its potential of composite repair through healing at the site of structure damage. Finally, the Joule heating effect of the LIG interlayers in cured FRCs is investigated and found to enable the fast and energy-efficient deicing of such composite structures. Therefore, the proposed OoA-curing method provides a simple and cost-efficient approach to manufacture FRCs with multifunctionality.
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