Papers by Keyword: Tension

Abstract: Evaluation is carried out on the operability of a 87,900 ton Sevan Stabilized Platform (SSP) functioned as an FPSO in the hypothetical operational site of Masela Block. This is to observe the critical conditions when side-by-side (SBS) offloading is performed between the SSP and a 35,000 DWT shuttle tanker. The first stage of analysis conducted on the moored SSP as a single floating body indicates the capability to withstand a 100-year wave, designated by the significant height of 8.0 m. Largest motions are experienced when SSP contains 75% load capacity, resulting in the mooring tension range from 2,000 kN up to 7,000 kN, portraying ample safety factors of 2.0 up to 3.0. The second stage of analysis is conducted for execution of SBS offloading from SSP to shuttle tanker, positioned in a 3.3 m distance. Observation is made when SSP is loaded with 100%, 83%, and 75% capacities correlated to the shuttle tanker loading of 10%, 60%, and 90% capacities. This reveals critical conditions arise when the wave exceeds 2.0 m in height, or the operability level of some 88.5%. Safer operation and higher operability level could be achieved by increasing the distance of SSP and shuttle tanker.

Abstract: The heterogeneity of manual arc welded samples of low-carbon steel St3sp meant for bridge construction to be used in Cameroon has been investigated. The chemical analysis of the material was carried out and the arc welding processes used, then the probes were subject to mechanical testing such as tensile test, low-cycle fatigue test, and micro hardness study. A total inclusion of weld defects in the specific welded sample and especially in the cyclic loading specimes has been discovered. Premature fracture was revealed below the plastic limit in some probes during the tension and low-cycle test. A micro structural examination and micro hardness measurements were done in order to determine what exactly could be the reason of this catastrophic failure. The structural analysis revealed the differences in mechanical properties conditioned by phase distribution and carbon content in weld, heat affected zone and base metal. To determine the heterogeneity in mechanical properties the elastic modulus distribution has been calculated due to relationship between the micro hardness and materials strength.

Abstract: One of the work cycles of reinforced concrete structures is the state of repair and reconstruction, including the steps of strengthening elements. The traditional types of strengthening of reinforced concrete which are steel and concrete collars and shirts - now are receding into the background. New methods of strengthening with modern materials such as lamellae are increasingly being used. The article deals with the issues related to strengthening the structures made of high-strength concrete using composite polymeric materials.

Abstract: The use of prefabricated mini silo structures enables us to build containers for grain or animal feed and to transport the structural elements to the installation site. Traditional types of strengthening of concrete structures are steel and concrete cages. Polymer materials are widely used in construction. The methods of strengthening modern materials, such as lamellae, are being increasingly used. The issue of strengthening the structures with composite polymer materials is relevant.

Abstract: The numerical analysis of stress-strain state of low-alloyed welded steel samples test has been considered. The mechanical heterogeneity has been estimated by the micro hardness test. The stress-strain state analysis is based on the models of linear elasticity, which are described by Lame equations for displacement. In this case the samples are considered as perfect welded samples without any welding defects. The discretization of the system of equations is done through the finite element method, and the numerical realization of the method is performed on collection of free software FEniCS. The defects influence has been estimated by stochastic modelling of viscous crack growth. The data for crack size in weld and heat affected zone was obtain from microscopic observation, and for mechanical properties from microhardness testing. The result obtained shows that, the distribution of displacement in all samples are almost the same. Between the welded zone, the heat affected zone and the external elliptic zone, the Von Mizes stress is almost the same in all three samples. Concerning the crack growth, the velocity of it propagation in welded zone is higher as much again than that in the heat affected zone. This research is beneficial to welders, modellers of structures, researches as a whole.

Abstract: The mechanical properties investigation results obtained by tension and indentation tests of RIP (resin impregnated paper) electric insulator are presented. Tension and indentation tests of the RIP electric insulation material in wide temperature range are conducted. The common relations between strength and temperature as well as between hardness and temperature for the RIP electric insulation are established. The ratio of ultimate tensile strength to Brinell hardness is performed to be constant (about 1/3) irrespective of temperature, that means a possibility of the RIP electric insulation mechanical properties evaluation by the instrumented indentation test.

Abstract: Using the material testing machine of electro-hydraulic servo fatigue tests had been carried out on ordinary concrete and steel fiber reinforced concrete. The fatigue life, strength, stress and strain had been measured under tension and compression loading. The variation of fatigue was analyzed based on the test results. Having regression analysis, obtained the fatigue strength. Mean-while, the fatigue strain-life curves of ordinary concrete and steel fiber reinforced concrete had been made after data processing. The results had been showed that the fatigue property of steel fiber reinforced concrete was significantly higher than that of ordinary concrete. And the fatigue strength increased about 32.6% compared with ordinary concrete. The tensile and compressive fatigue strain were slightly smaller than that of ordinary concrete.

Abstract: This paper is concerned with rate-dependent hardening behaviors of the TRIP980 steel sheet. In sheet metal forming, sheet metals experiences complicated loading at various strain rates. In order to predict deformed shape in sheet metal forming, accurate material properties and an appropriate constitutive model in numerical simulation are important to consider reverse loading and various strain rates simultaneously.This paper deals with rate-dependent material parameters of the isotropic/kinematic hardening model. Tension/compression tests of the TRIP980 steel sheet are performed with a newly developed experimental technique at various strain rates ranging from 0.001 to 100 s⁻¹. Tension/compression hardening curves of the TRIP980 steel sheet are approximated by the Chun et al model at each strain rate condition respectively. From acquired material parameters, rate dependencies of tension/compression hardening behaviors are investigated.

Abstract: This paper presents the research on the structure, short-term compression and tension of hemp fibers composite. The density of hemp fibers composite varied from ~40 to ~96 kg/m³. The mechanical characteristics of such hemp fibers composite mostly depend on the materials structure and density. By the mechanical tests it was determined that compressive stress of the hemp fibers composite depends on the direction of the load to the specimens face (perpendicular, across and parallel to the direction of formation).

Abstract: On the basis of experimental data, calculating diagrams of non-linear straining of fiber concrete under compression and tension were developed, which take into consideration the qualitative change in strength and stress-strain properties of the concrete matrix at its fiber reinforcement. The obtained diagrams are realized upon the bearing capacity calculation of fiber-reinforced concrete flexural elements. Calculation of fiber-reinforced beam was fulfilled according to the proposed approach and current regulatory documents. Comparison of calculation results was carried out, according to which the regulatory procedure gives an overstated result for its bearing capacity.