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Kenjayeva To'lg'onoy Rahmonovna, Hamidov Umrzoq Yusuf o'g'li, Tojiyev Abdulaziz Rasuljon o'g'li, …

Other affiliations: Southern Methodist University
Bio: Kenjayeva To'lg'onoy Rahmonovna, Hamidov Umrzoq Yusuf o'g'li, Tojiyev Abdulaziz Rasuljon o'g'li, … is an academic researcher. The author has contributed to research in topics: Composite material & Materials science. The author has an hindex of 3, co-authored 7 publications receiving 40 citations. Previous affiliations of Kenjayeva To'lg'onoy Rahmonovna, Hamidov Umrzoq Yusuf o'g'li, Tojiyev Abdulaziz Rasuljon o'g'li, … include Southern Methodist University.

Papers
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Journal ArticleDOI
TL;DR: In this article , a numerical model was developed using a coupling method modeled by utilizing ANSYS AQWA and Orcaflex (Orcina Ltd., Ulverston, UK) dynamic models of the CALM buoy hoses.
Abstract: There is an increase in the utilization of the floating offshore structure (FOS) called Catenary Anchor Leg Mooring (CALM) buoys and the attached marine hoses due to the increasing demand for oil and gas products. These hoses are flexible and easier to use but have a short service life of about 25 years. They are adaptable in ocean locations of shallow, intermediate and deep waters. In this research, a numerical model was developed using a coupling method modeled by utilizing ANSYS AQWA and Orcaflex (Orcina Ltd., Ulverston, UK) dynamic models of the CALM buoy hoses. Two cases were comparatively studied: Lazy-S and Chinese-lantern configurations, under ocean waves and current. Comparisons were also made between coupled and uncoupled models. This research presents the hydrodynamic characteristics with a sensitivity analysis on the influence of waves, current attack angle, soil gradient, soil stiffness and environmental conditions that influence the performance of marine hoses. The study comparatively looked at the configurations from dynamic amplification factors (DAF) on marine hoses. The results show that marine hoses can be easily configured to suit the designer’s need, seabed soil type, seabed topography and the profiles that are useful for manufacturers. The sensitivity analysis also shows the effect of hose parameters on its hydrodynamic behavior from the wave–current interaction (WCI).

10 citations

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TL;DR: In this paper , the thermal properties of CA-UHPC with coarse aggregates subjected to temperature ranged from 20 °C ∼ 900 °C, including changes in macro and micro morphology before and after high temperatures, thermal conductivity, mass loss, specific heat and thermal expansion.

9 citations

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TL;DR: In this paper, the thermal properties of UHPC with coarse aggregates (CA-UHPC) subjected to temperature ranged from 20°C to 900°C, including changes in macro and micro morphology before and after high temperatures.

9 citations

Journal ArticleDOI
TL;DR: In this paper , a two-step modeling strategy with consideration of primary pores is proposed to evaluate mechanical properties of random micro-fiber reinforced composites with considering of primary pore defects.
Abstract: This paper presents a novel procedure to evaluate mechanical properties of random micro-fiber reinforced composites with consideration of primary pores. To this end, micro-CT experiment is conducted first to detect micro-scale morphology of the constituent materials, including size of pores and arrangement of fibers, etc. On this basis, a two-step modeling strategy with consideration of primary pores is proposed. In the first step, the equivalent mechanical properties of the pore defects and the micro-fibers are determined by the 3D parametric finite volume directly averaging micromechanics (FVDAM), by which an equivalent ellipsoidal reinforcing phase composed of fibers and pores is constructed. In the second step, the equivalent pores and fibers are embedded into matrix materials to build an RVE of the composite to calculate the elastic modulus of the composite. In addition, the 3D parametric FVDAM is further extended to simulate plastic deformation of PEEK matrix under quasi-static tensile loading. The results obtained from the proposed two-step modeling strategy have a good agreement with the results from experiments.

3 citations

Journal ArticleDOI
TL;DR: In this article, a two-step modeling strategy with consideration of primary pores is proposed to evaluate mechanical properties of random micro-fiber reinforced composites with considering of primary pore defects.

3 citations


Cited by
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Journal ArticleDOI
TL;DR: In this article , the fluid-structure interaction (FSI) from wave diffraction forces on CALM buoys and cylindrical structures, based on the hydrodynamics with connections, was investigated.
Abstract: ABSTRACT This research fills the gap in understanding fluid–structure interaction (FSI) from wave diffraction forces on CALM buoys and cylindrical structures, based on the hydrodynamics with connections. Recently, there is an increased application of (un)loading marine hoses for Catenary Anchor Leg Moorings (CALM) buoy systems in the offshore industry due to the need for more flexible marine structures that are cost-saving, easier to install, and service. However, different operational issues challenge these hoses, like during hose disconnection. Also, the fluid behaviour was investigated based on the analytical and numerical models. The numerical modelling involves the boundary element method (BEM) and Orcaflex line theory. Hydrodynamic analysis is conducted on the disconnection-induced load response of marine bonded hoses during normal operation and accidental operation under irregular waves. A comparative study on hose performance during normal operation and accidental operation is also presented. Results of statistical analysis on CALM buoy system shows good motion characteristics.

20 citations

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TL;DR: In this article , a review on the design, hydrodynamics and mechanics of composite risers is presented, which covers both the structure of the composite production riser (CPR) and its end-fittings for offshore marine applications.
Abstract: 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.

18 citations

Journal ArticleDOI
TL;DR: In this paper , a detailed presentation on motion characterisation of the Catenary Anchor Leg Moorings (CALM) buoy hose system is presented, which is a structure with six degrees of freedom (6DoF) and a well-detailed experimental presentation on the CALM buoy hose model conducted in Lancaster University Wave Tank is presented using three novel techniques.
Abstract: The application of marine bonded hoses has increased in recent times, due to the need for more flexible conduits and flexible applications in the offshore industry. These marine structures include Catenary Anchor Leg Moorings (CALM) buoys and ocean monitoring buoys. Their attachments include floating hoses, submarine hoses and submarine cables. However, the structural performance challenges of a CALM buoy system from its hydrodynamics water waves and other global loadings, have led to the need for this investigation. In this study, a detailed presentation on the motion characterisation of the CALM buoy hose system is presented. The CALM buoy is a structure with six degrees of freedom (6DoF). A well-detailed experimental presentation on the CALM buoy hose model conducted in Lancaster University Wave Tank is presented using three novel techniques, which are: a digital image captured using Imetrum systems, using an Akaso 4K underwater camera, using wave gauges arranged in a unique pattern and using underwater Bluetooth sensors. The buoy model was also found to respond uniquely for each motion investigated under water waves. The results showed that the higher the profile, the higher the response of the buoy. Thus, this study confirms the existence of flow patterns of the CALM buoy while floating on the water body.

17 citations

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TL;DR: In this article , a finite element model was adopted to predict the deformation and mechanical response behavior of MBCH, and a mesh study was carried out on meshing the hose layers.
Abstract: Currently, the properties of composites have been harnessed on pipelines in the marine offshore industry. In this study, marine bonded composite hose (MBCH) is presented. It is aimed at understanding the stress/strain distribution on marine bonded hoses using local design pressure under burst and collapse cases. This study also investigates composite material modelling, hose modelling, liner wrinkling, helical spring deformation, and two MBCH models—with and without ovalisation. The ovalized model is considered the simplified model in this research. A mesh study was carried out on meshing the hose layers. In this study, local design pressure was considered and not operational pressure. This finite element model was adopted to predict the deformation and mechanical response behaviour of MBCH. From this study, composites could be considered to improve conventional marine hoses. The study findings include identification of buckled sections on the hose and stressed zones on the helix reinforcement. Highly reinforced hose ends are recommended in ends of the MBCH as they had maximum stress and strain values.

15 citations

Journal ArticleDOI
TL;DR: In this article , a detailed investigation on the mooring line analysis for two different configurations on the hull of a Paired Column Semisubmersible (PCSemi) is presented.

14 citations