In this work, accelerated thermal aging at different temperatures was performed on high-density polyethylene (HDPE) bottles and specimens for food packaging. The degradation of HDPE was followed macroscopically by tensile and compression tests to evaluate the decrease in mechanical properties. The data obtained from these tests are used to calculate a new static damage law and the life fraction of this polymer. A prediction of the lifetime of HDPE was determined by thermogravimetric analysis (TGA) in dynamic mode. The evolution of the crystallinity rate during accelerated thermal aging was carried out using FOURIER transform infrared spectrometry (FTIR). The results obtained show a remarkable degradation of the mechanical properties in traction and compression by calculation of the static damage, and the physical and chemical properties by the analysis of the rate of crystallinity as well as the prediction by the law of Arrhenius.

The dynamic behavior of the cylindrical shell can be predicted by more simplified beam models for a wide range of applications. The present paper deals with finding design conditions in which the cylindrical shell performs like a beam. Employing the Hamilton’s principle, the governing equations are obtained using both Donnell-Mushtari and Flugge shell theories and the analytical solution is obtained for long cylinders with simply-supported boundary conditions at both ends. Then, by equalizing the shell and beam vibration frequencies, the shell-to-beam transition conditions are obtained for both theories. To account for the effects of shear distortion and rotatory inertia of the shell, the finite element method is applied to find the best transition conditions with less approximating assumptions. Finally, the effects of boundary conditions on the transition parameters as well as the frequency response are studied. The obtained conditions simply define that if the shell can be assumed as a beam in any specific geometrical and material conditions.

This paper investigates the shear strength and failure modes of steel-concrete-steel (SCS) sandwich composite member with Engineered Cementitious Concrete (ECC) and explores the influences of various shear connectors such as headed stud and bolt on shear behavior of SCS sandwich composite member by carrying out push-out testing program. Based on the test results in this study, the failure modes and the load-slip behavior of the specimens are investigated. In addition, the experimental results on the shear resistance of the headed stud connector with various connector spacing and numbers of connector is compared and explored.

In reality, concrete structures are normally under various loadings, and results of different studies have shown that cracks in these structures and their materials, due to their nature as well as the loading type, do not develop along the crack plane (pure mode I); rather, they expand under mixed modes, making the crack growth studies under these modes a very important issue. In the crack growth phenomenon, the fracture toughness is a very effective parameter usually calculated by ENDB samples because they are easy to handle. In this study, several samples were made by changing the maximum aggregates size (dmax = 9.5, 12.5 & 19 mm) and the amount of hooked-end steel fibers (SF = 0.1, 0.3 & 0.5%), and tested under different loading modes (pure/mixed modes I and III) using the strain control jack device. According to the results, the lowest fracture toughness belonged to pure mode III, aggregates with dmax = 12.5 mm performed better in the self-compacting concrete reinforced with steel fiber, Also, the results show that the increasing trend of steel fibers does not have a positive effect on the fracture toughness performance.

The interconnected usefulness of titanium grade 5 is amplified by the improved mechanical ability and sustainable applications in various industries like the aerospace, medical industry and many more. Despite the profound properties of Ti6Al4V, it is worthy of intellectual study to investigate the possible performance improvement of the material for better operational application. This study adopted the use of RF magnetron sputtering to deposit the target on the substrate material under varying temperatures and deposition power. A total of four samples and control were analyzed for a surface morphological examination and post-sputtering chemical compositional analysis via SEM (scanning electron microscope) and EDX (energy dispersive x-ray analysis). Further investigation on the samples' crystallites was done using XRD (X-ray diffractometer). The SEM images showed low agglomeration and most of the samples were void of pores, cleft and crevices, which implied homogeneous distribution of the target (Inconel thin film) on the titanium substrate. The EDX of the Inconel coated titanium samples revealed elements such as Ti, Si and C, which are beneficial to the properties of the materials. The XRD profiles of the Inconel coated titanium samples disclosed intensities of high peaks, which indicated stability, chemical and microstructural homogeneity of the thin film.

Leaf springs are machine elements that provide safety and driving comfort by storing the energy caused by the loads coming to the chassis and transport elements depending on the road conditions. Leaf springs are suspension elements commonly used particularly in heavy commercial vehicles. In this study, prototype leaf spring production was realized by forming the metal sheet and making heat treatments. Residual stress analysis, hardness, bending and strain gauge measurements were performed to examine the mechanical properties of the leaf spring produced. After the applied tempering process, the leaf spring microstructure was examined.

The behavior of clay minerals in expansive soils causes them to exhibit shrink-swell characteristics, making them unsuitable for engineering purposes in their natural state. To address this problem, researchers conducted direct shear experiments using fly ash as an admixture and black cotton soil as an expanding soil to explore the strength parameter. The experiments were conducted with varying amounts of fly ash ranging from 2% to 20%. Two arrangements of test series were made, and in the principal series, tests were made utilizing five unique densities and comparing dampness contents. The outcomes showed that the point of inside grating and union expanded directly up to the ideal dampness content and most significant dry thickness before diminishing. The subsequent series showed that the end of inward rubbing grew straightly with the expansion of fly debris admixture, yet attachment reduced after 10% admixture. The decrease in shear strength was because of the diminished passion, as the fly debris' cohesionless attributes took over as the admixture rate increased above 10%. Based on these findings, adding fly ash in small quantities to black cotton soil is recommended to avoid weakening it.

Since the late 80’s the Structural Analysis Research Group of the Instituto Superior Técnico (IST) has been involved in the development of non-conventional finite element formulations in order to overcome some of the limitations associated with the use of the CFE method and to develop high performance numerical tools for the analysis of structural engineering problems. Several alternative models for the linear and non-linear structural analysis have been developed using hybrid and mixed models techniques. These works are summarized in this paper, in which their past and future applications of this formulation in non-linear analysis of structures are fully detailed.

In recent years, nano-filler-based hybrid composites have gained significant attention from the research community; The nano-filler-based hybrid composites can have potential applications in numerous sectors. Nano-fillers are bringing a leading development in material science and natural fibers-based composites. The present study considers the impact of various weight percentages of nano-titanium oxide (NTiO2) fillers (2%, 4%, and 6%) on the elastic features of novel hybridized banana-hemp fiber-reinforced epoxy composites. The proposed composite is analyzed for its elastic properties like longitudinal and transverse elastic modulus, axial Poisson's ratio, and axial shear modulus using homogenized micromechanical models, namely, Mori-Tanaka (M-T) model, Generalized self-consistent (G-SC) model and Modified Halpin-Tsai (M-HTS) model. The composite is modeled using one layer of banana fiber, one layer of NTiO2 and epoxy, and one layer of hemp fiber. All three layers of the composite are arranged in the sequence of banana fiber at 450, a layer of NTiO2 and epoxy at 00, and hemp fiber at 450. The proposed composite's vector sum deformation and strength are examined by employing the ANSYS APDL application. The results obtained in this study are compared with the experimental work mentioned in the literature. The composite reinforced with six weight% NTiO2 has the highest mechanical strength, and the modified Halpin-Tsai (M-HTS) model is the most effective in calculating the elastic features of the proposed composite. In addition to the above, the hybridization effect for the proposed composite is also estimated to analyze the tensile failure strain of banana and hemp fiber in the proposed hybrid composite structure.

The development of land use in Badung Regency in the period 2013-2021 has an impact on changes in the ecological structure of the landscape. Changes in the ecological structure of the landscape occur in the three parameters, namely patch, matrix and corridor, which are indicated by changes in the area and function of the three parameters. The addition of matrix area in the settlement land use class and golf course patches causes changes in the area of the matrix of mixed gardens, rice fields and mangroves as well as corridors of non-volcanic coastal sand that dominantly have ecological functions. The objectives to be achieved in this study are to analyze the dynamics of changes in the ecological structure of the landscape caused by land use development in Badung Regency. The dynamics of changes in the ecological structure of the landscape due to large-scale changes is a driving factor in the deviation of spatial utilization and a decrease in the quality of the environment in Badung Regency. The research concluded that landscape ecology analysis is an important aspect in the development of regional zones in Badung Regency that takes into account the principles of sustainable development. This research found a new formulation in the analysis of ecological zone development that integrates the landscape ecology approach with the spatial approach and regional approach. The ecological zones of Badung Regency are grouped into 4 (four), namely: very high ecological zone, high ecological zone, medium ecological zone and low ecological zone.