In this work, we aim to provide a concise overview of the analytical techniques for describing the in-plane and out-of-plane stress fields in radiused-notched orthotropic materials. To facilitate this objective, an introductory summary of complex potentials is offered in orthotropic elasticity, particularly regarding plane stress or strain and antiplane shear cases. Moving forward, the attention is directed towards the key expressions describing the notch stress fields, considering elliptical holes, symmetrical hyperbolic notches, parabolic notches (representing blunt cracks), and radiused V-notches. Ultimately, real-world applications demonstrate the effectiveness of the presented analytical solutions, comparing them with results from numerical analyses in corresponding cases.

In the context of this research, a new, swiftly implemented method was designed and named StressLifeHCF. Using classic fatigue testing in conjunction with non-destructive material response monitoring during cyclic loading, a process-oriented determination of fatigue life can be achieved. This procedure requires the execution of two load increases and two constant amplitude tests. Employing data from non-destructive assessments, the elastic parameters, per Basquin's model, and the plastic parameters, per Manson-Coffin's model, were ascertained and integrated into the StressLifeHCF calculation. Two supplemental variations of the StressLifeHCF technique were designed to enable an accurate delineation of the S-N curve over a more extensive area. 20MnMoNi5-5 steel, classified as a ferritic-bainitic steel (16310), was the primary subject of this research. The spraylines of German nuclear power plants frequently rely on this steel. For verification purposes, additional trials were carried out utilizing SAE 1045 steel (11191).

A structural steel substrate received a deposition of a Ni-based powder, a blend of NiSiB and 60% WC, through the dual application of laser cladding (LC) and plasma powder transferred arc welding (PPTAW). A comparative study was conducted on the resulting surface layers. The solidified matrix from both methods saw secondary WC phase precipitation, with the PPTAW cladding uniquely presenting a dendritic microstructure. Despite the identical microhardness values of the clads created via both procedures, the PPTAW clad showed a stronger resistance to abrasive wear, surpassing the LC clad. The transition zone (TZ) demonstrated a thin profile for each method, featuring a coarse-grained heat-affected zone (CGHAZ) and macrosegregation patterns resembling peninsulas in the clads produced by both techniques. Due to the thermal cycling, the PPTAW clad showcased a unique cellular-dendritic growth solidification (CDGS) and a type-II boundary within its transition zone (TZ). Despite both procedures resulting in metallurgical bonding of the clad to the substrate, the LC technique demonstrated a lower dilution coefficient. The LC method demonstrably produced a heat-affected zone (HAZ) larger in size and harder compared to that of the PPTAW clad. Analysis of this study's results reveals that both approaches show potential for anti-wear applications, attributed to their wear resistance and the metallurgical bonding they form with the underlying material. Applications demanding superior resistance to abrasive wear might find PPTAW cladding particularly advantageous, contrasting with LC methods, which are preferable when lower dilution and a larger heat-affected zone are key requirements.

Polymer-matrix composites are prevalent in a multitude of engineering applications. Nevertheless, environmental conditions exert a substantial influence on their macroscopic fatigue and creep behaviors, stemming from multiple mechanisms operating at the microscopic level. Within this analysis, we investigate the effects of water intake leading to swelling and eventually hydrolysis, provided sufficient time and quantity. this website Because of the combination of high salinity, pressure, low temperature, and the presence of biological materials, seawater exacerbates fatigue and creep damage. Other liquid corrosive agents, similar to the first, permeate cracks formed due to cyclic loading, thereby dissolving the resin and breaking the interfacial bonds. Either increasing the crosslinking density or disrupting polymer chains within a given matrix's surface layer is a consequence of UV radiation exposure, leading to embrittlement. Temperature fluctuations near the glass transition negatively impact the fiber-matrix interface, leading to microcracking and compromising fatigue and creep resistance. Microbial and enzymatic processes in the degradation of biopolymers are researched, with microbes specializing in the metabolism of specific matrices, resulting in modifications to microstructure and/or chemical composition. Specific details regarding the impact of these environmental factors are presented for epoxy, vinyl ester, and polyester (thermosets), polypropylene, polyamide, and polyetheretherketone (thermoplastics), and polylactic acid, thermoplastic starch, and polyhydroxyalkanoates (biopolymers). The detrimental environmental factors described affect the fatigue and creep capabilities of the composite, causing alterations in mechanical properties or creating stress concentrations via micro-cracks, thus expediting the onset of failure. Research in the future should extend to matrices different from epoxy, and also the creation of standardized testing procedures.

The high viscosity of high-viscosity modified bitumen (HVMB) renders conventional, short-term aging procedures inappropriate. Hence, this research endeavors to introduce a fitting short-term aging methodology for HVMB, incorporating an extended aging period and increased temperature. Two commercially available HVMB types underwent aging treatments through the implementation of rolling thin-film oven testing (RTFOT) and thin-film oven testing (TFOT), at different aging periods and temperatures. Two aging methods were applied to open-graded friction course (OGFC) mixtures produced with high-viscosity modified bitumen (HVMB), mirroring the brief aging of bitumen during mixing plant operations. The rheological behavior of short-term aged bitumen and extracted bitumen was determined through the use of temperature sweep, frequency sweep, and multiple stress creep recovery tests. Through a comparative study of the rheological properties between extracted bitumen and TFOT- and RTFOT-aged bitumens, laboratory short-term aging schemes for high-viscosity modified bitumen (HVMB) were developed. The comparative analysis demonstrated that aging the OGFC mixture within a 175°C forced-draft oven for two hours effectively replicates the short-term aging process of bitumen occurring at mixing plants. TFOT was deemed more suitable than RTOFT in the context of HVMB. Regarding TFOT, the advised aging duration is 5 hours, and the corresponding temperature is 178 degrees Celsius.

Silver-doped graphite-like carbon (Ag-GLC) coatings were applied to aluminum alloy and single-crystal silicon via magnetron sputtering, with the deposition parameters carefully controlled to ensure diverse outcomes. A study was conducted to determine the impact of silver target current, deposition temperature, and the introduction of CH4 gas flow on the spontaneous migration of silver from within the GLC coatings. In addition, the ability of Ag-GLC coatings to resist corrosion was examined. The results pertaining to spontaneous silver escape at the GLC coating proved consistent across all preparation conditions. soluble programmed cell death ligand 2 The three preparatory factors all affected how the escaped silver particles were distributed in size, number, and arrangement. However, unlike the silver target current and the introduction of CH4 gas flow, only varying the deposition temperature yielded a significant positive impact on the corrosion resistance of the Ag-GLC coatings. Corrosion resistance was optimal for the Ag-GLC coating at a deposition temperature of 500°C, this outcome resulting from the reduced silver particle migration from the coating at elevated temperatures.

While soldering with metallurgical bonding achieves firm sealing of stainless-steel subway car bodies, compared to the method of rubber sealing, the corrosion resistance of these joints has been scarcely studied. Two prevalent solders were selected and implemented for the soldering of stainless steel in this research, and their attributes were investigated. The experimental results highlighted the advantageous wetting and spreading properties of the two solder types on the stainless steel plates, successfully creating sealed connections between the stainless steel sheets. The Sn-Sb8-Cu4 solder, in the context of comparison with the Sn-Zn9 solder, exhibits a lower solidus-liquidus, making it more apt for low-temperature sealing brazing. Genetic material damage The two solders exhibited a sealing strength exceeding 35 MPa, a notable enhancement compared to the current sealant, with a sealing strength below 10 MPa. The Sn-Zn9 solder exhibited a heightened susceptibility to corrosion and a substantial increase in corrosion extent compared with the Sn-Sb8-Cu4 solder, throughout the corrosion process.

Indexable inserts are currently the prevalent tool for material removal in contemporary manufacturing processes. Experimental insert shapes and, most significantly, internal structures like coolant channels, are now producible using additive manufacturing techniques. An investigation into the procedure for efficiently fabricating WC-Co components with internal coolant channels is presented, highlighting the crucial role of achieving an appropriate microstructure and surface finish, especially within the coolant channels. To begin this study, we analyze the process parameters required to achieve a microstructure that is free from cracks and possesses minimal porosity. The following stage prioritizes and focuses exclusively on the improvement of the parts' surface quality. The internal channels are the focus of meticulous examination, with true surface area and surface quality undergoing careful evaluation because they critically affect coolant flow. Ultimately, WC-Co specimens were successfully produced, exhibiting a microstructure with both low porosity and no cracks. This success was facilitated by the identification of an effective parameter set.