Characterization and Failure Analysis of Plastics

Volume 11B serves as a reference and guide to help engineers determine the causes of failure in plastic components and make corrective adjustments through design and manufacturing modifications. It contains seven major divisions, covering polymer science and processing, material selection and design, chemical, thermal, and physical analysis, mechanical behavior and testing, degradation mechanisms, systematic failure analysis, and life assessment and optimization. It examines a wide range of factors that contribute to the properties and behaviors of engineering plastics and the effect of thermal and mechanical stresses, impact loading, fatigue, wear, weathering, moisture and chemical exposure, photochemical aging, microbial degradation, and elevated temperatures. It addresses issues such as flammability, environmental stress cracking, crazing, and stress whitening and describes the unique characteristics of polymer fracture and how to assess and predict service life using fracture mechanics. It also presents and analyzes numerous examples of failure, including design and manufacturing related failures, wear failures of reinforced plastics, and failures due to creep and yielding.

Design and Static Stress Analysis of Double Wishbone Suspension

Double Wishbone suspension systems are by far the best choice of suspension systems recommended for sports vehicles. It is more stable and stiffer when compared to the other suspension geometries. In this report a brief study of how a double-wishbone suspension system acts under loading conditions when traveling at high speeds is presented, also the forces acting on its components are analysed, and post-processed results are discussed. The geometry of the whole suspension is designed on SolidWorks and analysis is performed on Ansys software. Further the results from the analysis are studied based on material selection and various analysis methods. Finally, the proposed suspension system is concluded safe to use when the values of Equivalent stress, Total Deformation, and Factor of Safety were measured and under threshold limits. Keywords: double wishbone suspension, static structural, suspension system, analysis, deformation, Ansys, stress analysis, FOS, FEA, structural analysis.

Helmet-Riding to the Next Generation

A helmet is a type of head protection that is worn on the head. By decreasing the impact of a force or collision to the head, a helmet seeks to lessen the risk of significant head and brain injuries. The shell, EPS liner, Comfort liner, Cheek pads, Visor, and Retention or closing mechanism are the different sections of a helmet. The outer shell of a motorcycle helmet can be made lighter and more comfortable by using materials that reduce weight and absorb energy. Metal foams are a type of cellular material that has a number of fascinating qualities, including high stiffness and low specific weight, as well as effective energy absorption. These distinct features make them suitable for a wide range of applications, from car bumpers to aircraft crash recorders. Keywords: Helmet, Material Selection, CFRP, Bluetooth

Post exenteration surgery rehabilitation with orbital prosthesis – A case report

Orbital defects with total loss of eyelids and the eyeball cannot be satisfactorily repaired by reconstructive surgery. Therefore, a prosthetic placement is the treatment of choice to return the individual’s confidence by producing an acceptable and lifelike appearance. Male patient, 31 years old, came with history of exenteration surgery four months ago on right eye because of infection few years before. Patient wanted orbital prosthesis to improve esthetic and self-confidence. He lost his right eye ball and some part of right eyelid. Treatment of choice that would be fabricated was orbital prosthesis with medical adhesive retention support. Orbital prosthesis was one of the alternative that can be chose to reconstruct orbital defect. The success of the prosthesis was determined by the exactness of diagnosis, treatment plan determination, material selection, determination of prosthesis retention, and technique in processing the prosthesis.

Single-valued neutrosophic Einstein interactive aggregation operators with applications for material selection in engineering design: case study of cryogenic storage tank

Single-valued neutrosophic sets (SVNSs) and their application to material selection in engineering design. Liquid hydrogen is a feasible ingredient for energy storage in a lightweight application due to its high gravimetric power density. Material selection is an essential component in engineering since it meets all of the functional criteria of the object. Materials selection is a time-consuming as well as a critical phase in the design process. Inadequate material(s) selection can have a detrimental impact on a manufacturer’s production, profitability, and credibility. Multi-criteria decision-making (MCDM) is an important tool in the engineering design process that deals with complexities in material selection. However, the existing MCDM techniques often produce conflicting results. To address such problems, an innovative aggregation technique is proposed for material selection in engineering design based on truthness, indeterminacy, and falsity indexes of SVNSs. Taking advantage of SVNSs and smooth approximation with interactive Einstein operations, single-valued neutrosophic Einstein interactive weighted averaging and geometric operators are proposed. Based on proposed AOs, a robust MCDM approach is proposed for material selection in engineering design. A practical application of the proposed MCDM approach for material selection of cryogenic storage containers is developed. Additionally, the authenticity analysis and comparison analysis are designed to discuss the validity and rationality of the optimal decision.

Mineralogical and Geochemical Characteristics of Carbonate Rocks for Lime Industry in Ban Pong, Chiang Mai Province, Northern Thailand

One of the oldest lime manufactures in Chiang Mai Province is located in a hillside village, Ban Pong, Hang Dong District, the western part of Chiang Mai City. Villagers still have conserved traditional production methods using wood-fired kilns and the primary material selection, an Ordovician marble. There are 2 massive amounts of carbonate rocks distributed in Chiang Mai Province; Permian limestone and Ordovician marble. However, the Ordovician carbonate rocks in Ban Pong were selected to produce high-quality lime by their primitive method (man-made) for a long time. Petrographical studies suggest that the Ordovician rock samples show a granoblastic texture with a slightly foliation represents by mica flakes. They are made up mainly of calcite, with very small amounts of quartz, muscovite, talc, and opaque minerals that can be identified as marble. The mineral compositions are according to the value of CaO, SiO2, Al2O3, K2O, and Fe2O3 in whole-rock analysis by XRF. The geochemical data suggest that marble in the Ban Pong area has a high CaO ratio and contains small amounts of muscovite, quartz, talc, and opaque minerals that may reduce the decomposition temperature during the calcination process. The Ordovician marble in Ban Pong is an appropriate raw material for traditional lime manufacture to saving energy in the production system. HIGHLIGHTS Limestone has been a geologic material in the lime industry from the past to the presence of human society Villagers in Ban Pong (Chiang Mai Province, Thailand) selected the western Ordovician limestone mountains to produce lime by a primitive process instead of the eastern Permian limestone mountains The mineral- and chemical compositions of the Ordovician limestones were intensively analyzed to characterize the suitable raw materials for a primitive lime kiln The mineral composition indicated that the Ordovician limestone in this area is metamorphosed into an impure fine-grained marble GRAPHICAL ABSTRACT

Mechanical Properties of Bisacryl-, Composite-, and Ceramic-resin Restorative Materials

SUMMARY Objective: Resin-based materials used in restorative dentistry are introduced at a fast pace with limited knowledge about their properties. Comparing properties of these materials from different restorative categories is lacking but can help the clinician in material selection. This study aimed to compare mechanical properties and wear resistance of bis-acryl-, composite-, and ceramic-resin restorative materials. Methods and Materials: Bisacryl-resin (Bis-R, LuxaCrown, DMG), composite-resin (Com-R, Filtek Supreme Ultra, 3M Oral Care), and ceramic-resin (Cer-R, Enamic, VITA Zahnfabrik) specimens were prepared for mechanical tests: fracture toughness (FT) with and without initial thermomechanical loading using a mastication simulator, flexural strength (FS), and flexural modulus (FM), compressive strength (CS), and volumetric wear loss measurement. The datasets for FT and wear resistance were each analyzed using two-way ANOVA followed by pairwise comparisons or Tukey testing as appropriate. The datasets for FS, FM, and CS were analyzed using one-way ANOVA followed by the Tukey test. Results: Analysis of FS, FM, and CS showed significant differences between materials, with all pairwise comparisons between materials showing significance. Analysis of FT resulted in a significant interaction between the material and treatment, with analysis of wear loss showing a significant interaction between the material and the number of cycles. Conclusions: Cer-R demonstrated superior FT, CS, and wear resistance compared to Bis-R and Comp-R materials. Fracture toughness of Bis-R increased after thermomechanical loading.

The Role of Biomimicry on Visual Design Education

The change and increasing diversity in communication tools with globalization have ensured the universal presentation of visual elements shaped by local cultural patterns. Today, design products have turned into a strategic tool for many countries in order to reach higher competitive power. As the visual design industry contributes as an important visual communication and marketing tool for different industries within and outside the creative sector, its role in ensuring sustainability becomes even more important. Graphic design is much more effective, direct, and fast than other means of information in order to develop environmental awareness and motivate desired behaviors. The biomimetic graphic is a design process and style that has been spread and passed along throughout today’s culture and society via various channels and networks of communication. In today's world, where globalization and associated social and environmental problems are increasing, design education plays an important role in the development of sustainable design products. In design education, the students should be taught the concepts of ecological material selection, environmentally friendly energy use, recycling, reconsideration, and reuse. In this study, the role of biomimicry in visual design education will be examined with sample applications. In addition to new skills and knowledge in design education, sustainability will emerge as an important feature sought in designers soon.

Exposure of FeCrAl Overlay Welds on Superheater Tubes: Influence of Local Environment on Degradation

Two experimental FeCrAl alloy overlay welds on tube shields were exposed in the superheater of a full-size waste fired boiler for 6 months. The tube shields were in different tube lines and positions within the superheater chamber to investigate possible heterogeneities in the exposure environment. The visual inspection of the exposed tube shields and the corrosion-erosion rates calculated from the analysis of cross-sections showed that the mid-length roof location experienced the most aggressive environment. The compositional differences between the two experimental alloys were not found to be determinant in their performance under these specific exposure conditions. It was concluded that erosion had a decisive influence on the results. The identification of local differences within the superheater chamber is important when deciding on the material selection for the different areas and locations to be protected. The output of this study is therefore interesting for further design consideration of superheaters as well as for future planning of exposures.