Laboratory Investigation of the Mechanical Properties of a Rubber–Calcareous Sand Mixture: The Effect of Rubber Content

This paper introduces a rubber–calcareous sand mixture as a lightweight building material in offshore engineering. The mechanical properties of mixtures of varying rubber contents were investigated by performing a one-dimensional (1-D) compression test in a modified oedometer cell, as well as a resonant column test. A discussion on the test results, along with detailed interpretations regarding the role of rubber chips in the mixtures, are provided. It was found that the virgin compression curves of the rubber–calcareous sand mixtures tended to converge at a certain stress level, whilst the stress level depended on the rubber content. Moreover, the relative breakage was examined by comparing the particle size distribution curves of the calcareous sand before and after the compression test. It was shown that the grain crushing of calcareous sand was less remarkable with the inclusion of rubber chips. Furthermore, the small strain shear modulus (G0) of the mixtures decreased with the rubber content, yet the modulus reduction and damping curves exhibited little difference for the specimens of varying rubber contents.

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The Effects of Anodizing Process on the Corrosion rate and Fatigue Life of Aluminum Alloy 7075-T73

Engineering and Technology Journal ◽

10.30684/etj.v38i1a.1594 ◽

2020 ◽

Vol 38 (1A) ◽

pp. 34-42

Author(s):

Ibrahim M. AL-Sudani ◽

Samir A. Al-Rabii ◽

Dhafir S. Al-Fattal

Keyword(s):

Mechanical Properties ◽

Aluminum Alloy ◽

Sulfuric Acid ◽

Fatigue Life ◽

Aluminum Alloys ◽

Corrosion Rate ◽

Stress Level ◽

Mechanical Characteristics ◽

Before And After ◽

Aluminum Alloy 7075

This research aims to study the effect of using the anodizing process on the corrosion rate, mechanical properties as well as the fatigue life for aluminum alloy (7075-T73), which is one of the most commonly used aluminum alloy in production of aircrafts, vehicles and ships structures. The anodizing process was employed through using sulfuric acid for time (20) min in a salty atmosphere. The mechanical properties and fatigue life of the AA7075-T73 were obtained before and after the anodizing process. All the results were listed in detailed tables and figures for comparison purpose. Generally, these results showed a decrease in corrosion rate by (155.06%) in comparison with untreated, an increase in hardness by (21.54%) and a slight decrease in fatigue life by (7.7%) due to anodizing for a time of 20 min at the stress level of (σa = 491.10 MPa). It was concluded that this technique could be applied on other aluminum alloys in order to know the magnitude of change in the mechanical characteristics and their fatigue life.

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Sunlight exposure: the effects on the performance of paragliding fabric

Industria Textila ◽

10.35530/it.069.05.1406 ◽

2018 ◽

Vol 69 (05) ◽

pp. 381-389

Author(s):

MENGÜÇ GAMZE SÜPÜREN ◽

TEMEL EMRAH ◽

BOZDOĞAN FARUK

Keyword(s):

Mechanical Properties ◽

Aging Process ◽

Air Permeability ◽

Sunlight Exposure ◽

Test Results ◽

Coating Materials ◽

Strength Tests ◽

Before And After ◽

The Relationship ◽

Dark Blue

This study was designed to explore the relationship between sunlight exposure and the mechanical properties of paragliding fabrics which have different colors, densities, yarn counts, and coating materials. This study exposed 5 different colors of paragliding fabrics (red, turquoise, dark blue, orange, and white) to intense sunlight for 150 hours during the summer from 9:00 a.m. to 3:00 p.m. for 5 days a week for 5 weeks. Before and after the UV radiation aging process, the air permeability, tensile strength, tear strength, and bursting strength tests were performed. Test results were also evaluated using statistical methods. According to the results, the fading of the turquoise fabric was found to be the highest among the studied fabrics. It was determined that there is a significant decrease in the mechanical properties of the fabrics after sunlight exposure. After aging, the fabrics become considerably weaker in the case of mechanical properties due to the degradation in both the dyestuff and macromolecular structure of the fiber

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Effects of Different Types of Fibers on the Physical and Mechanical Properties of MICP-Treated Calcareous Sand

Materials ◽

10.3390/ma14020268 ◽

2021 ◽

Vol 14 (2) ◽

pp. 268

Author(s):

Jitong Zhao ◽

Huawei Tong ◽

Yi Shan ◽

Jie Yuan ◽

Qiuwang Peng ◽

...

Keyword(s):

Mechanical Properties ◽

Water Absorption ◽

Glass Fiber ◽

Physical And Mechanical Properties ◽

Polyester Fiber ◽

Engineering Properties ◽

Fiber Types ◽

Calcite Precipitation ◽

Calcareous Sand ◽

Hemp Fiber

Microbial-induced calcite precipitation (MICP) has been a promising method to improve geotechnical engineering properties through the precipitation of calcium carbonate (CaCO3) on the contact and surface of soil particles in recent years. In the present experiment, water absorption and unconfined compressive strength (UCS) tests were carried out to investigate the effects of three different fiber types (glass fiber, polyester fiber, and hemp fiber) on the physical and mechanical properties of MICP-treated calcareous sand. The fibers used were at 0%, 0.10%, 0.15%, 0.20%, 0.25%, 0.30%, 0.35%, and 0.40% relative to the weight of the sand. The results showed that the failure strain and ductility of the samples could be improved by adding fibers. Compared to biocemented sand (BS), the water absorption of these three fiber-reinforced biocemented sands were, respectively, decreased by 11.60%, 21.18%, and 7.29%. UCS was, respectively, increased by 24.20%, 60.76%, and 6.40%. Polyester fiber produced the best effect, followed by glass fiber and hemp fiber. The optimum contents of glass fiber and polyester fiber were 0.20% and 0.25%, respectively. The optimum content of hemp fiber was within the range of 0.20–0.25%. Light-emitting diode (LED) microscope and scanning electron microscope (SEM) images lead to the conclusion that only a little calcite precipitation had occurred around the hemp fiber, leading to a poor bonding effect compared to the glass and polyester fibers. It was therefore suggested that polyester fiber should be used to improve the properties of biocemented sand.

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Study on improvement of prefolded energy absorption device to constant resistance and its mechanical properties

Science Progress ◽

10.1177/00368504211036820 ◽

2021 ◽

Vol 104 (3) ◽

pp. 003685042110368

Author(s):

Dong An ◽

Jiaqi Song ◽

Hailiang Xu ◽

Jingzong Zhang ◽

Yimin Song ◽

...

Keyword(s):

Mechanical Properties ◽

Energy Absorption ◽

Compression Test ◽

Side Wall ◽

Concave Side ◽

Displacement Curve ◽

Static Compression ◽

Constant Resistance ◽

The Impact ◽

Force Displacement

When the rock burst occurs, energy absorption support is an important method to solve the impact failure. To achieve constant resistance performance of energy absorption device, as an important component of the support, the mechanical properties of one kind of prefolded tube is analyzed by quasi-static compression test. The deformation process of compression test is simulated by ABAQUS and plastic strain nephogram of the numerical model are studied. It is found that the main factors affecting the fluctuation of force-displacement curve is the stiffness of concave side wall. The original tube is improved to constant resistance by changing the side wall. The friction coefficient affects the folding order and form of the energy absorbing device. Lifting the concave side wall stiffness can improve the overall stiffness of energy absorption device and slow down the falling section of force-displacement curve. It is always squeezed by adjacent convex side wall in the process of folding, with large plastic deformation. Compared with the original one, the improved prefolded tube designed in this paper can keep the maximum bearing capacity ( Pmax), increase the total energy absorption ( E), improve the specific energy absorption (SEA), and decrease the variance ( S2) of force-displacement curve.

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Effects of equal channel angular pressing and heat treatments on the microstructures and mechanical properties of selective laser melted and cast AlSi10Mg alloys

Archives of Civil and Mechanical Engineering ◽

10.1007/s43452-021-00246-y ◽

2021 ◽

Vol 21 (3) ◽

Author(s):

Przemysław Snopiński ◽

Mariusz Król ◽

Marek Pagáč ◽

Jana Petrů ◽

Jiří Hajnyš ◽

...

Keyword(s):

Mechanical Properties ◽

Low Temperature ◽

Equal Channel Angular Pressing ◽

Heat Treatments ◽

Electron Backscattered Diffraction ◽

Angular Pressing ◽

Low Temperature Annealing ◽

Transmission Electron ◽

Before And After ◽

The Impact

AbstractThis study investigated the impact of the equal channel angular pressing (ECAP) combined with heat treatments on the microstructure and mechanical properties of AlSi10Mg alloys fabricated via selective laser melting (SLM) and gravity casting. Special attention was directed towards determining the effect of post-fabrication heat treatments on the microstructural evolution of AlSi10Mg alloy fabricated using two different routes. Three initial alloy conditions were considered prior to ECAP deformation: (1) as-cast in solution treated (T4) condition, (2) SLM in T4 condition, (3) SLM subjected to low-temperature annealing. Light microscopy, transmission electron microscopy, X-ray diffraction line broadening analysis, and electron backscattered diffraction analysis were used to characterize the microstructures before and after ECAP. The results indicated that SLM followed by low-temperature annealing led to superior mechanical properties, relative to the two other conditions. Microscopic analyses revealed that the partial-cellular structure contributed to strong work hardening. This behavior enhanced the material’s strength because of the enhanced accumulation of geometrically necessary dislocations during ECAP deformation.

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Fast Preparation of High-Performance Wood Materials Assisted by Ultrasonic and Vacuum Impregnation

Forests ◽

10.3390/f12050567 ◽

2021 ◽

Vol 12 (5) ◽

pp. 567

Author(s):

Hong Yang ◽

Mingyu Gao ◽

Jinxin Wang ◽

Hongbo Mu ◽

Dawei Qi

Keyword(s):

Mechanical Properties ◽

High Performance ◽

Mechanical Tests ◽

Vacuum Impregnation ◽

Natural Forests ◽

Ultrasonic Pretreatment ◽

Fast Growing ◽

Before And After ◽

New Material ◽

Ft Ir

In the absence of high-quality hardwood timber resources, we have gradually turned our attention from natural forests to planted fast-growing forests. However, fast-growing tree timber in general has defects such as low wood density, loose texture, and poor mechanical properties. Therefore, improving the performance of wood through efficient and rapid technological processes and increasing the utilization of inferior wood is a good way to extend the use of wood. Densification of wood increases the strength of low-density wood and extends the range of applications for wood and wood-derived products. In this paper, the effects of ultrasonic and vacuum pretreatment on the properties of high-performance wood were explored by combining sonication, vacuum impregnation, chemical softening, and thermomechanical treatments to densify the wood; then, the changes in the chemical composition, microstructure, and mechanical properties of poplar wood before and after treatment were analyzed comparatively by FT-IR, XRD, SEM, and mechanical tests. The results showed that with ultrasonic pretreatment and vacuum impregnation, the compression ratio of high-performance wood reached its highest level and the MOR and MOE reached their maximums. With the help of this method, fast-growing softwoods can be easily prepared into dense wood materials, and it is hoped that this new material can be applied in the fields of construction, aviation, and automobile manufacturing.

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Microstructure and Mechanical Properties of Ti-6Al-4V Manufactured by SLM

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.651-653.677 ◽

2015 ◽

Vol 651-653 ◽

pp. 677-682 ◽

Cited By ~ 33

Author(s):

Anatoliy Popovich ◽

Vadim Sufiiarov ◽

Evgenii Borisov ◽

Igor Polozov

Keyword(s):

Mechanical Properties ◽

Heat Treatment ◽

Phase Composition ◽

Mechanical Behavior ◽

Ductile Fracture ◽

Elevated Temperatures ◽

Initial Material ◽

Laser Melting ◽

Microstructure And Mechanical Properties ◽

Before And After

The article presents results of a study of phase composition and microstructure of initial material and samples obtained by selective laser melting of titanium-based alloy, as well as samples after heat treatment. The effect of heat treatment on microstructure and mechanical properties of specimens was shown. It was studied mechanical behavior of manufactured specimens before and after heat treatment at room and elevated temperatures as well. The heat treatment allows obtaining sufficient mechanical properties of material at room and elevated temperatures such as increase in ductility of material. The fractography of samples showed that they feature ductile fracture with brittle elements.

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