A parametric study of masonry infilled steel frames

2001 ◽  
Vol 28 (1) ◽  
pp. 149-157 ◽  
Author(s):  
J L Dawe ◽  
Y Liu ◽  
C K Seah
Keyword(s):  
Aspect Ratio ◽  
Peak Load ◽  
Steel Frames ◽  
Local Stress ◽  
Concrete Block ◽  
Stress Concentrations ◽  
Aspect Ratios ◽  
Wide Range ◽  
Different Types ◽  
Increased Strength

A previously developed computer model was used to investigate the effects of a wide range of parameters applicable to concrete block masonry infilled steel frames. Height to length panel aspect ratios were varied from 0.5 to 1.5 to reflect how other parameters were affected by these values. Eight different types of parameters were studied. The method of applying horizontal load was found to have little effect. Isolation gaps between panel and beam reduced both the stiffness and strength of the infilled frame. While panel-to-column ties generated an increase in peak load, local stress concentrations caused by the ties resulted in additional deterioration of the panel. Strength was found to vary with mortar joint bond strength, with the effects being more significant at higher aspect ratios. Increasing beam stiffness increased strength for low aspect ratio frames, and increasing column stiffness had a similar effect for high aspect ratio frames. Gravity loading was beneficial in increasing shear resistance up to a limit where it caused crushing of the masonry infill. The increases in strength of infilled frames were found to be disproportionate to increases in the strength of the masonry.Key words: masonry, steel, infill, frame, analytical, variables, shear, strength, deflection, interaction.

scholarly journals Strength Analysis of Alternative Airframe Layouts of Regional Aircraft on the Basis of Automated Parametrical Models

Aerospace ◽  
2021 ◽  
Vol 8 (3) ◽  
pp. 80
Author(s):  
Dmitry V. Vedernikov ◽  
Alexander N. Shanygin ◽  
Yury S. Mirgorodsky ◽  
Mikhail D. Levchenkov
Keyword(s):  
Aspect Ratio ◽  
High Aspect Ratio ◽  
High Performance ◽  
Strength Analysis ◽  
Labor Input ◽  
Aerodynamic Loading ◽  
Aspect Ratios ◽  
Wide Range ◽  
Parametrical Design

This publication presents the results of complex parametrical strength investigations of typical wings for regional aircrafts obtained by means of the new version of the four-level algorithm (FLA) with the modified module responsible for the analysis of aerodynamic loading. This version of FLA, as well as a base one, is focused on significant decreasing time and labor input of a complex strength analysis of airframes by using simultaneously different principles of decomposition. The base version includes four-level decomposition of airframe and decomposition of strength tasks. The new one realizes additional decomposition of alternative variants of load cases during the process of determination of critical load cases. Such an algorithm is very suitable for strength analysis and designing airframes of regional aircrafts having a wide range of aerodynamic concepts. Results of validation of the new version of FLA for a high-aspect-ratio wing obtained in this work confirmed high performance of the algorithm in decreasing time and labor input of strength analysis of airframes at the preliminary stages of designing. During parametrical design investigation, some interesting results for strut-braced wings having high aspect ratios were obtained.

scholarly journals Influence of Pile Diameter and Aspect Ratio on the Lateral Response of Monopiles in Sand with Different Relative Densties

2021 ◽  
Vol 9 (6) ◽  
pp. 618
Author(s):  
Huan Wang ◽  
Lizhong Wang ◽  
Yi Hong ◽  
Amin Askarinejad ◽  
Ben He ◽  
...  
Keyword(s):  
Aspect Ratio ◽  
Large Diameter ◽  
Pressure Coefficient ◽  
Offshore Wind ◽  
Fe Model ◽  
Soil Pressure ◽  
Pile Diameter ◽  
Centrifuge Tests ◽  
Aspect Ratios ◽  
Wide Range

The large-diameter monopiles are the most preferred foundation used in offshore wind farms. However, the influence of pile diameter and aspect ratio on the lateral bearing behavior of monopiles in sand with different relative densities has not been systematically studied. This study presents a series of well-calibrated finite-element (FE) analyses using an advanced state dependent constitutive model. The FE model was first validated against the centrifuge tests on the large-diameter monopiles. Parametric studies were performed on rigid piles with different diameters (D = 4–10 m) and aspect ratios (L/D = 3–7.5) under a wide range of loading heights (e = 5–100 m) in sands with different relative densities (Dr = 40%, 65%, 80%). The API and PISA p-y models were systematically compared and evaluated against the FE simulation results. The numerical results revealed a rigid rotation failure mechanism of the rigid pile, which is independent of pile diameter and aspect ratio. The computed soil pressure coefficient (K = p/Dσ′v) of different diameter piles at same rotation is a function of z/L (z is depth) rather than z/D. The force–moment diagrams at different deflections were quantified in sands of different relative density. Based on the observed pile–soil interaction mechanism, a simple design model was proposed to calculate the combined capacity of rigid piles.

Natural Convection of Cu-Gallium Nanofluid in Enclosures

2011 ◽  
Vol 133 (12) ◽  
Author(s):  
Cong Qi ◽  
Yurong He ◽  
Yanwei Hu ◽  
Juancheng Yang ◽  
Fengchen Li ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Nusselt Number ◽  
Natural Convection ◽  
Aspect Ratio ◽  
Convection Heat Transfer ◽  
Low Velocity ◽  
Grashof Number ◽  
Aspect Ratios ◽  
Wide Range ◽  
Temperature Dependent Properties

In this work, the natural convection heat transfer of Cu-gallium nanofluid in a differentially heated enclosure is investigated. A single-phase model is employed with constant or temperature-dependent properties of the fluid. The results are shown over a wide range of Grashof numbers, volume fractions of nanoparticles, and aspect ratios. The Nusselt number is demonstrated to be sensitive to the aspect ratio. It is found that the Nusselt number is more sensitive to thermal conductivity than viscosity at a low velocity (especially for a low aspect ratio and a low Grashof number), however, it is more sensitive to the viscosity than the thermal conductivity at a high velocity (high aspect ratio and high Grashof number). In addition, the evolution of velocity vectors, isotherms, and Nusselt number for a small aspect ratio is investigated.

Secondary Flow and Hydraulic Losses Within Sinuous Conduits of Rectangular Cross Section

1992 ◽  
Vol 114 (4) ◽  
pp. 593-600 ◽  
Author(s):  
Yukimaru Shimizu ◽  
Yoshiki Futaki ◽  
C. Samuel Martin
Keyword(s):  
Aspect Ratio ◽  
Secondary Flow ◽  
Cross Section ◽  
Rectangular Cross Section ◽  
Flow Patterns ◽  
Geometric Configuration ◽  
Hydraulic Losses ◽  
Aspect Ratios ◽  
Wide Range ◽  
The Relationship

This paper describes the relationship between hydraulic losses and secondary flow within sinuous conduits with complicated bends. It has been found that the nature of secondary flow present in the bends is quite sensitive to the geometric configuration of the bend and the actual aspect ratio of the conduit section. Indeed, many different secondary flow patterns have been found to exist as the bend geometry is altered. A wide range of experiments has been conducted for various aspect ratios of a rectangular conduit with different curvatures.

scholarly journals Near Surface Characteristic: Hybrid Fiber Reinforced Concrete With Different Aspect Ratio

2019 ◽  
Vol 8 (3) ◽  
pp. 1025-1028
Keyword(s):  
Reinforced Concrete ◽  
Aspect Ratio ◽  
Water Absorption ◽  
Surface Characteristics ◽  
Fiber Reinforced Concrete ◽  
Fiber Reinforced ◽  
Hybrid Fiber ◽  
Near Surface ◽  
Aspect Ratios ◽  
Different Types

The present work is enhancement of near surface characteristics for hybrid fiber reinforced concrete (aspect ratio 40+100). Here in this research work an attempt has made to study water absorption values for different types of fiber reinforced concrete, which are having different aspect ratios like 40, 100 and 40+100. Concrete mix along with fibers are casted and cured for 28days. Both water absorption test and sorptivity tests carried on hardened concrete. The main objective is to check variation in absorption values due to addition of different types of fibers. Here totally five different types of fibers are considered like steel fiber, Galvanized iron fibres, High density polyethylene fibres, waste plastic fiber and polypropylene fibers Experimental investigation shows that except polyprolene hybrid mix concrete other hybrid mixes has showed good results. But as compared to mono fiber reinforced concrete hybrid fiber reinforced concrete has showed better results. This research was aimed to provide benchmark for future research works on near surface characteristics of hybrid fiber reinforced concrete.

Design guidelines to mitigate distortion in material jetting specimens

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Kamran Kardel ◽  
Ali Khoshkhoo ◽  
Andres L. Carrano
Keyword(s):  
Aspect Ratio ◽  
Layer Thickness ◽  
Design Guidelines ◽  
Geometrical Parameters ◽  
Content Type ◽  
Build Orientation ◽  
Aspect Ratios ◽  
Wide Range ◽  
The Difference ◽  
Part Thickness

Purpose The purpose of this paper is to investigate the effects of layer thickness, aspect ratio, part thickness and build orientation on distortion to have a better understanding of its behavior in material jetting technology. Design/methodology/approach Specimens with two layer thicknesses (14 and 28 µm) were printed in two aspect ratios (2:1) and (10:1), four thickness values (1, 2, 3 and 4 mm) and three build orientations (45d, XY and YX) and scanned with a wide-area 3D surface scanner to quantify distortion. The material used to build the test specimens was a commercially available resin, VeroWhitePlus RGD835. Findings The results of this study showed that all printed specimens by material jetting 3D printers had some level of distortion. The 1-mm thickness specimens, for both layer thicknesses of 14 µm and 28 µm, showed a wide range of anomalies including reverse coil set (RCS), reverse cross bow (RCB), cross bow (CB), wavy edge (WE) and some moderate twisting (T). Similar occurrences were observed for the 2-mm thickness specimens as there were RCS, WE, RCB and T anomalies that show the difference between the thinner specimens (1- and 2-mm) with the thicker ones (3- and 4-mm). In both 3- and 4-mm thickness specimens, there was more consistency in terms of distortion with mainly RCS and RCB anomalies. In total, six different types of flatness anomalies were found to occur with the following incidences: reverse coil set (91 specimens, 63.19%), reverse cross bow (50 specimens, 34.72%), wavy edge (23 specimens, 15.97%), twist (19 specimens, 12.50%), coil set (11 specimens, 7.64%) and cross bow (7 specimens, 4.86%). Originality/value This study expands the research on how the preprocess parameters such as layer thickness and build orientation and the geometrical parameters such as part thickness and aspect ratio cause dimensional distortion. Distortion is a pervasive consequence of the curing process in photopolymerization and explores one of the most common defects that come across in polymeric-based additive manufacturing. In addition to the characterization of the type and magnitude of distortion, the contributions of this work also include establishing the foundation for design guidelines aiming at minimizing distortion in material jetting.

An Experimental Study of Confined Masonry Walls with Varying Aspect Ratios

2015 ◽  
Vol 31 (2) ◽  
pp. 945-968 ◽  
Author(s):  
J. J. Perez Gavilan ◽  
L. E. Flores ◽  
S. M. Alcocer
Keyword(s):  
Aspect Ratio ◽  
Good Accuracy ◽  
Axial Stress ◽  
Masonry Walls ◽  
Inelastic Behavior ◽  
Ductility Demand ◽  
Confined Masonry ◽  
Aspect Ratios ◽  
Wide Range ◽  
Good Agreement

Results from an experimental series of seven full-scale confined masonry walls with height-to-length aspect ratios ( H/L) from 0.3 up to 2.2 are summarized. Results show that neither the level of axial stress nor the aspect ratio had a significant effect on lateral stiffness. Inelastic behavior of the walls, characterized by normalized stiffness degradation with ductility demand, can be estimated with good accuracy with a bilinear function for a ductility demand up to 4.5. A substantial increase in normalized shear strength was observed for walls with decreasing aspect ratio. A correction factor to the nominal cracking strength was deduced based on differences of the flexural deformations for squat and square walls. The factor was then compared to the experimental normalized strength with good agreement. A new expression for inclined cracking shear that can be used for a wide range of wall aspect ratios is proposed.

Evaluation of Stress Intensity Factor Interactions Between Adjacent Flaws With Large Aspect Ratios

2015 ◽  
Author(s):  
Kisaburo Azuma ◽  
Yinsheng Li ◽  
Kunio Hasegawa
Keyword(s):  
Stress Intensity ◽  
Aspect Ratio ◽  
Large Aspect Ratio ◽  
Finite Element Analyses ◽  
Intensity Factors ◽  
Membrane Stress ◽  
Combination Rules ◽  
Aspect Ratios ◽  
Wide Range ◽  
Factor Interactions

Multiple flaws detected during in-service inspections are evaluated in accordance with the flaw combination rules provided in the ASME B&PV Code Section XI. The rules treat adjacent two flaws as a single combined flaw if the distance between the two flaws is equal to or less than half of the flaw depth. That is, the combination rules are consisted of flaw depth basis. However, its applicability has not been clarified systematically to the flaws with large aspect ratio, the depth of which are greater than half its length. Interactions of stress intensity factors for multiple flaws under membrane stress were investigated using finite element analyses. The numerical results suggest that the flaw combination rules might be better to use flaw length basis, instead of flaw depth, over a wide range of the aspect ratio.

Analysis of Piezoelectric Energy Harvesters of a Moderate Aspect Ratio With a Distributed Tip Mass

2011 ◽  
Vol 133 (4) ◽  
Author(s):  
Jae Eun Kim ◽  
Yoon Young Kim
Keyword(s):  
Aspect Ratio ◽  
Finite Length ◽  
Three Dimensional ◽  
Element Model ◽  
Parameter Study ◽  
Beam Model ◽  
Aspect Ratios ◽  
Piezoelectric Energy ◽  
Wide Range ◽  
Tip Mass

Various mathematical beam models have been proposed for the efficient analysis of a piezoelectric energy harvester (PEH) and carrying out parameter study but there appears no beam model suitable for a PEH of a moderate width-to-length aspect ratio with a distributed tip mass, and so, moderate width-to-length aspect ratios and distribution effects of a tip mass over a finite length will be mainly focused on in the present beam analysis. To deal with a wide range of aspect ratios, the material coefficients appearing in the constitutive equations of a PEH beam will be interpolated by those of the limiting plane-strain and plane-stress conditions. The key idea in the interpolation is to derive the interpolation parameter analytically by using the fundamental frequency of a cantilevered beam of moderate aspect ratios. To deal with the distribution effects of a tip mass over a finite length, the use of a set of polynomial deflection shape functions is proposed in the assumed mode approach. The equations to predict the electrical outputs based on the proposed enhanced beam model are explicitly expressed in template forms, so one can calculate the outputs easily from the forms. The validity and accuracy were checked for unimorph and bimorph PEHs by comparing the results from the developed beam model, the conventional beam model, and a three-dimensional finite element model. The comparisons showed substantial improvements by the developed model in predicting the electrical outputs.

Flaw Tolerance for Multiple Fatigue Cracks

2005 ◽  
Author(s):  
S. R. Gosselin ◽  
F. A. Simonen ◽  
R. G. Carter
Keyword(s):  
Aspect Ratio ◽  
Nuclear Power ◽  
Power Plants ◽  
Fatigue Cracks ◽  
Fatigue Cracking ◽  
Low Alloy Steels ◽  
Aspect Ratios ◽  
Flaw Tolerance ◽  
Wide Range ◽  
Stress Ratios

Appendix L of Section XI provides for serviceability assessments of piping components that are subject to fatigue stresses. This appendix introduced a damage tolerance examination strategy to assure that components perform reliably throughout operating periods between inspections. Operating periods are based on fatigue crack growth analyses of postulated pre-existing cracks. Evidence from service experience shows that fatigue cracking occurrences at operating nuclear power plants often result from mechanisms that cause cracks to initiate and then grow at multiple locations on the inside surface of a pipe, becoming longer and deeper, and eventually linking to form a single long crack. This paper documents important details of the technical bases for changes to Appendix L. Calculations identified aspect ratios for equivalent single cracks (ESC) between the extremes of a 6:1 ratio and a full circumferential crack that can be used in Appendix L flaw tolerance assessments to account for the initiation, growth, and linking of multiple fatigue cracks. Probabilistic fracture mechanics (PFM) calculations determined ESC aspect ratios that result in the same through-wall crack probability as multiple small cracks (0.02 inch depth) that initiate and coalesce. The computations considered two materials (stainless and low alloy steels), three pipe diameters, five cyclic membrane-to-gradient stress ratios and a wide range of primary loads. Subsequent deterministic calculations identified the ESC aspect ratio for the hypothetical reference flaw depth assumptions in Appendix L. This paper also describes computations that compare the Appendix L flaw tolerance allowable operating period for the ESC models with results obtained when a single default 6:1 aspect ratio reference flaw.

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