Top PDF Research of brick dynamic strength when subjected to shock loading by method of computer modelling

Research of brick dynamic strength when subjected to shock loading by method of computer modelling

Research of brick dynamic strength when subjected to shock loading by method of computer modelling

the "steel-brick" adjoining surface were defined by using the graphic approach with the impact adiabats of steel and brick. In Fig. 1, there are calculation data of the dynamic strength of the masonry fragment, consisted of four bricks with 1 cm mortar bed between them. The data are represented by the time of the impact shock of the steel falling weight of 500 kg at 2 m height, being on the pile-driver (V 0 = 6,26 m/s, u 0 = 6,1 m/s, P 0 = 0,04 GPa,

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Two Dimensional Stress and Displacement Wave Propagation Under Shock Loading in Saturated Porous Materials with Two Dimensional Functionally Graded Materails Using MLPG Method

Two Dimensional Stress and Displacement Wave Propagation Under Shock Loading in Saturated Porous Materials with Two Dimensional Functionally Graded Materails Using MLPG Method

A meshless technique based on the MLPG method with heaviside step function as the weight function is employed to investigate the effects of the material gradation on displacements and stresses wave propagation in the porous medium around the borehole, which is subjected to the shock loading. For this purpose, two dimensional exponential grading patterns for the shear modulus, coupling parameters between the solid and fluid and permeability are considered in the excavation disturbed zone. To interpolate the fields’ variables in terms of its nodal values, the radial point interpolation method (RPIM) with radial basis function (RBF) is used. The main results of the presented research can be summarized as follows:
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Numerical Modelling of Wind Turbine Foundations subjected to Combined Loading

Numerical Modelling of Wind Turbine Foundations subjected to Combined Loading

the design codes do not have any provision for calculating tensile capacity. Especially in the case of a wind turbine foundation, this becomes significant as the foundation loses its contact with the soil due to the uplifting forces of wind (albeit for very short periods of time). With innovations occurring in the fast growing wind industry, the design codes and the analysis of embedded foundations may also need to be assessed to optimize wind turbine foundation design. Use of the finite element method to predict the ultimate bearing capacities of foundations has emerged as one of the most popular methods among geotechnical researchers. With higher computer speed, memory and data storage capacity in the recent years, this method has increasingly been used to express explicitly the bearing capacity of a footing with realistic 3D geometries under general loading in terms of failure envelopes in Vertical, Horizontal and Moment (VHM) loading space. Bransby and Randolph (1998), Gourvenec and Randolph (2003), Salgado et al. (2004), Taiebat and Carter (2010), Shen et al. (2016) studied the effects of soil strength heterogeneity, shapes and embedments on the bearing capacity of offshore foundations under general loading and expressed the results in the form of dimensionless loads (bearing capacity factors) and failure envelopes. These results have been compared with those of conventional methods or design codes, to obtain an idea of ‘spare’ or ‘overlooked’ capacity. This helps to reduce foundation sizes, minimizing the construction costs and allows reuse of foundations. However, most of these studies were confined to strip or circular foundations. The interface between the foundation and the soil was usually assumed to be fully bonded [except Taiebat and Carter (2010), Shen et al. (2016)]. Hence, given these facts, different footing geometries (like octagonal), contact conditions like a no-tension interface and soil conditions such as a surficial crust, that are specific to wind turbine foundations in Canada need to be investigated, to gain further insight into the foundation design.
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Research of dynamic properties of alloys of AMg6BM and AMg6M in shock-wave experiment on a gas gun

Research of dynamic properties of alloys of AMg6BM and AMg6M in shock-wave experiment on a gas gun

Aluminum alloys of the system Al-Mg (magnalia) combine good strength and high plasticity, have high processibility, are well distorted, have satisfactory corro- sion resistance and good fusability. This determines wide application of these alloys in atomic industry, building industry, aviation, rocket building, in constructions subjected to high thermal and force loadings [1,2]. Russian industry proves semifinished alloyAMg6 in the form of sheets, rods, foils, profiles in thermally unprocessed (AMg6), annealed (AMg6M), with technological cladding of sheets (AMg6BM) or without cladding (AMg6M), in cold-worked (AMg6N) and other states of products. Prediction of the results of pulse impact on such structures is an important practical task. In order to solve this task, it is necessary to know dynamic, kinematic and thermophysical properties of such structures [3, 4].
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An Experimental Study on Strength of Concrete with Silica Fume and Partial Replacement of Cement by Brick Powder

An Experimental Study on Strength of Concrete with Silica Fume and Partial Replacement of Cement by Brick Powder

Brick powder reduce the weight of the concrete. Increase in construction activities. Brick crushed in coarse powder were used in cement for making concrete. With proper mix design concrete with brick powder will increase the strength. As curing age increases the compressive strength will be increased.

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Galvanically enhanced fretting-crevice corrosion of cemented femoral stems

Galvanically enhanced fretting-crevice corrosion of cemented femoral stems

passive Ti alloy ring and fretting contact. This is not surprising and has been shown by many authors (Guadalupe Maldonado et al., 2013; Landolt et al., 2001; Stack and Chi, 2003) that by increasing the over-potential of a system, wear-corrosion transitions can be observed depending the nature of the alloy. This paper highlights the need and importance of developing and taking a systems approach (i.e. understanding the interactions between other components rather than studying them in isolation) when considering the degradation mechanisms of orthopaedic alloys. Electrochemical reactions occurring across other interfaces have the ability to accelerate or supress the dissolution mechanisms at localised interfaces. This will have a drastic effect on the overall performance of the construct which will not be captured when interfaces are studied in isolation.
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Static Stress and Fatigue Analysis on Vertical Stabilizer of a Typical Trainer Aircraft

Static Stress and Fatigue Analysis on Vertical Stabilizer of a Typical Trainer Aircraft

Abstract: Recent survey concludes that fatigue failure results in many fatal accidents to the aircrafts. So in order to reduce fatigue failure, static stress and fatigue analysis have been done for vertical stabilizer of a typical trainer aircraft at +4g factor condition. Design modeling of component is done using CATIA V5 software. Static stress analysis has been done using Patran and Nastran software. Aluminium 7075 T6 material which has high fatigue strength has been used in vertical stabilizer. From the static stress analysis, maximum principal stress value has been found out which is less than the yield strength of Al 7075 T6. The maximum principal stress value has been used in fatigue calculation and the obtained analytical result shows the safe number of factored fatigue life hours for the component. The result predicted in this work concludes the efficient number of factored fatigue life hours for the vertical stabilizer which would reduce the service cost of the component and ensures structural safety to the component. Keywords: Fatigue failure – fatal - static stress analysis - fatigue analysis -vertical stabilizer - +4g factor - CATIA V5 - Patran, Nastran - Al 7075 T6 - efficient-factored fatigue- life hours-service cost-structural safety.
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A Proposed Method to Evaluate Ultimate Resistance of Plate Girders Subjected to Shear and Patch Loading (RESEARCH NOTE)

A Proposed Method to Evaluate Ultimate Resistance of Plate Girders Subjected to Shear and Patch Loading (RESEARCH NOTE)

Abstract Experimental investigation of the ultimate resistance of slender, steel-plate girder web panels to combined shear-and-patch loading indicates significant interaction between shear loading and patch loading. However, an existing interaction formula is based on experimental results. Herein, an improved design procedure for slender plate girders subjected to combined shear and patch loading is proposed. A modified formula to evaluate shear resistance of plate girders in presence of patch loading is proposed that shows satisfactory correlation with the available test data and is acceptable for practical purposes.
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Normal Strength Steel Fiber Reinforced Concrete Subjected to Explosive Loading

Normal Strength Steel Fiber Reinforced Concrete Subjected to Explosive Loading

Generally the failure modes on structure associates with the explosive loading can be flexure, direct shear or punching shear, bleaching and spalling which is depended on the explosive size and standoff distance between the blast source and the target as shown Figure 5.0.[17] The extend of the damaged on a structure can be classified as light, moderate and also severe. Light damaged is referring to the appearance of hair line crack with crack width of less than 1 mm on the exposed surface of the concrete. Moderate damaged refers to the situation when the bottom surface of the concrete is having cracks width of up to 1.5 mm and also having a minor spalling. Severe damage refers to the large cracks up to 4 mm wide together with large deflection and also heavy concrete spalling [18].
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Potential of RHA in foamed concrete subjected to dynamic impact loading

Potential of RHA in foamed concrete subjected to dynamic impact loading

When structure of concrete loaded by impact loading, it different responses when they are given static loading. Concrete subjected by impact loading generate localized effect. It is characterised by penetration, perforation, cratering or scabbing and more widespread crack propagation. The concrete should be sufficient in compressive strength to prevent the impact loading, while a higher tensile strength of concrete could be reduce a crater size and impede the fracture [10]. This is contrary properties of concrete as a shield structure, according on Dancygier and Yankelevsky [11], they observed their experiment study of the response of high strength concrete to hard projectile impact that the higher compressive strength more resistance against dynamics punch, but the higher compressive strength also increase the brittleness of concrete and generate the wider crater size diameter and produce more fragments. Microstructure analysis of lightweight concrete specifically for porous or aerated concrete such as FC, define that the interfacial zone of lightweight concrete should be lesser dimension than that of normal-weight concrete [12]. The formation of interfacial zone of FC is partly due to the lack of wall effect (i.e. high porosity at the interfacial zone) and partly due to the interlocking of the cement paste onto rough surface pores of FC, it is likely that the large pores size at the interfacial zone of FC. It causes weaken the strength of FC. A compacted interfacial zone helps to realize a higher strength of lightweight concrete [13], such as FC.
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Strength of coffee beans under static and dynamic loading

Strength of coffee beans under static and dynamic loading

Schematic of the experimental device used for the dynamic loading is shown in the Fig.2. Coff ee bean is placed on the wood rod and impacted by the falling bar. The bar is made from aluminium alloy. Its length is 200 mm, diameter of the bar is 6 mm. The bar is allowed to fall freely for a pre – selected height. The instrumentation of the bar by the strain gauges (semiconducting, 3 mm in length) enables to record time history of the force at the area of bar – coff ee bean contact. The same instrumentation is used for the supporting wood bar. It enables to record a force transmitted by the coff ee bean to the bar.
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Experiment and finite element analysis of U-profile subjected to dynamic loading

Experiment and finite element analysis of U-profile subjected to dynamic loading

Hand in hand with above mentioned goes the trend of reduction of greenhouse gas emission. Automotive industry addresses the trend by reduction of fuel consumption by lowering the car body weight thanks to high strength steels application. There is a direct correlation between weight of vehicle and fuel consumption. A 10% of weight reduction can lead to 1.9-8.2% savings in fuel consumption [2]. According to the study performed be Forschungsgesellschaft Kraftfahrwesen mbH Aachen (FKA) [3], vehicle mass can be reduced by 25% through the application of modern AHSS steel and 50% by application of aluminium. Using e.g. AISI301 in the B-pillar leads to lightening by 1.8kg (24%) compared to DP600 which has been used until now [4].
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Dynamic Response of RC Panel with and Without Openings Subjected To Blast Loading

Dynamic Response of RC Panel with and Without Openings Subjected To Blast Loading

In present study dynamic response of RC panel with and without opening were studied by finite element method using Abaqus application. The experimental work carried out by [8] was first validated by Abaqus to demonstrate its suitability. The results of response of reinforced concrete panel subjected to blast loading were represented in form of central deflection δ and normalized peak deflection δ/h. The thicknesses h of the slabs are 30 mm, 40 mm and 50 mm.The behaviour of concrete was simulated using concrete damaged plasticity model while plastic kinematic model used for simulation of steel. Subsequently, a parametric study on RC panel, with and without openings, are studied for the typical blast load scenarios. The response under the action of applied blast load were presented in form of displacement time history, distribution of compressive damage variable and distribution of tensile damage variable
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Dynamic properties of unbonded, multi-strand beams subjected to flexural loading

Dynamic properties of unbonded, multi-strand beams subjected to flexural loading

Each configuration was constrained and loaded as a beam subjected to three-point flexure (see Figure 1) with a sinusoidal load as in the quasi-static experiments detailed in Section 2. Numerical results were compared with the data from the quasi-static experiments. The clamping force was simulated as a uniform pressure along both the outer-upper and outer-lower surfaces of the beam as this was found to be more convenient than applying point loads at the clamp locations. To provide co nsistency with earlier experimental work, the term “clamp force” is still used but it should be noted that the contact force generated by the pressure was the same as the contact pressure generated by two clamps: thus, a clamp force of 250 N is represented as a pressure of 0.139 MPa.
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Dynamic Modeling of a Suspended and Shock Isolated System in Seismic Loading

Dynamic Modeling of a Suspended and Shock Isolated System in Seismic Loading

After letting the system reach equilibrium, a step function will apply a 6 inch displacement in the positive x direction. This is expected to result in the x coordinate for the platform’s CG to oscillate until reaching a new equilibrium from 11.5 to 12 ft. The x coordinate is expected to oscillate due to the platform rotations which develop from the sudden x movement. There are no mechanisms within the system to directly damp movement or forces in the x or y directions. However, the motion in the x direction is expected to be damped out over time and reach an equilibrium. This is because with each rotation about the y axis, a small component of the side loads applied to the system will act in the 𝑧𝑧 ′ direction of the body fixed frame, which will be damped by the shock absorbers.
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Fracture Analysis Of FRP Composites Subjected To Static and Dynamic Loading

Fracture Analysis Of FRP Composites Subjected To Static and Dynamic Loading

From fig 19. It is observed that by increasing the a/b ratio, the SIF is increasing. This is due to the crack propagation; material separation and energy release rate is high as the crack grows. However the variation of SIF with respect to number of layers is not linear. It is observed that the SIF for the plate with 4 and 8 layers is same and for plate with 2 layers SIF is very high as compared to all other layers. Due to symmetry lay up and when the crack is parallel to fiber direction the SIF is more and when it is in transverse direction the SIF is less .
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Earthquake Analysis of RC Building Using Clay Infill with Regular and Irregular Geometry

Earthquake Analysis of RC Building Using Clay Infill with Regular and Irregular Geometry

Reinforced concrete frame buildings have become common form of construction with masonry infills in urban and semi urban areas in the world. The term infilled frame denotes a composite structure formed by the combination of a moment resisting plane frame and infill walls. The infill masonry may be of brick, concrete blocks, or stones. In the current practice of structural design in India infill walls are considered as non-structural elements and their strength and stiffness contribution are neglected. The effect of infill panels on the response of reinforced concrete frames subjected to seismic action is widely recognized and has been subject of numerous experimental and analytical investigations over last five decades. The framed building behaves differently as compared to a bare framed building (without any infill) or a fully infilled framed building under lateral load. A bare frame is much less stiff than a fully infilled frame; it resists the applied lateral load through frame action and shows well-distributed plastic hinges at failure. In this study high rise buildings of regular and irregular geometry with 200 mm clay infill thickness under earthquake Zones-V with different infill positions are considered so as to evaluate the efficient building frame. These are achieved by comparing the result with different parameter like moment, shear force, peak displacement and drift.
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Relationships Between Prior Experiences, Current Teaching Contexts, and Novice Teachers' Use of Concrete Representation for Mathematics Instruction

Relationships Between Prior Experiences, Current Teaching Contexts, and Novice Teachers' Use of Concrete Representation for Mathematics Instruction

travel with an identical velocity. Therefore, all frequency components are preserved and there is no geometric dispersion of a propagating shear wave [22]. This is of great consequence when extracting specimen stresses and strains, as it is vital to the underlying theory that the strain pulses observed at the strain gages on the bars, which are placed some distance from the specimen, accurately depict the pulses present at the specimen-bar interfaces. Further difficulties in SPHB testing arise as a result of radial inertia effects in the specimen. Due to the Poisson effect, the specimen will tend to expand radially. This expansion is opposed by the inertia of the specimen and also by the friction present at the interfaces between the specimen and the bars. Although these effects can again be minimized by lubricating the specimen-bar interface and carefully selecting bar and specimen geometry, a purely compressive stress state is impossible to achieve. Neither friction nor inertia are of concern with use of the TSHB, however, as the Poisson effect and interfacial friction are absent [22].
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Enhancing the Compressive Strength of the Fly Ash  Brick by Fibre Reinforcement

Enhancing the Compressive Strength of the Fly Ash Brick by Fibre Reinforcement

In 5 C proportion, the materials used to cast the bricks are flyash, quarry dust and Ordinary Portland Cement (OPC) and the fibre coconut coir (CC). Here, the coconut coir is used as a replacement in the percentage of flyash. So the percentage of the materials used in the proportion will be of about 55% flyash, 30% quarry dust, 10% OPC and 5% coconut coir. From the compression strength test conducted, the results were found increasing gradually on increase of days. When compared to the normal mix and this, the strength increases due to the addition of fibre, also weight of the brick reduces. The usage of the fibre creates a strong link inside the brick thus it holds the brick even it gets cracks at its normal state, the further loading is carried by the fibre and makes the bricks to withstand heavy loadings.
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Functional adaptation to mechanical loading in both cortical and cancellous bone is controlled locally and is confined to the loaded bones

Functional adaptation to mechanical loading in both cortical and cancellous bone is controlled locally and is confined to the loaded bones

In order to validate whether bones' functional adaptation to mechanical loading is a local phenomenon, we randomly assigned 21 female C57BL/6 mice at 19 weeks of age to one of three equal numbered groups. All groups were treated with isoflurane anesthesia three times a week for 2 weeks (approximately 7 min/day). During each anaesthetic period, the right tibiae/ fi bulae in the DYNAMIC + STATIC group were subjected to a peak dynamic load of 11.5 N (40 cycles with 10-s intervals between cycles) superimposed upon a static “pre- load” of 2.0 N. This total load of 13.5 N engendered peak longitudinal strains of approximately 1400 microstrain on the medial surface of the tibia at a middle/proximal site. The right tibiae/ fi bulae in the STATIC group received the static “pre-load” alone while the NOLOAD group received no artificial loading. After 2 weeks, the animals were sacrificed and both tibiae, fibulae, femora, ulnae and radii analyzed by three- dimensional high-resolution (5 μ m) micro-computed tomography ( μ CT). In the DYNAMIC + STATIC group, the proximal trabecular percent bone volume and cortical bone volume at the proximal and middle levels of the right tibiae as well as the cortical bone volume at the middle level of the right fibulae were markedly greater than the left. In contrast, the left bones in the DYNAMIC + STATIC group showed no differences compared to the left or right bones in the NOLOAD or STATIC group. These μCT data were confirmed by two- dimensional examination of fluorochrome labels in bone sections which showed the predominantly woven nature of the new bone formed in the loaded bones. We conclude that the adaptive response in both cortical and trabecular regions of bones subjected to short periods of dynamic loading, even when this response is sufficiently vigorous to stimulate woven bone formation, is confined to the loaded bones and does not involve changes in other bones that are adjacent, contra-lateral or remote to them.
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