scholarly journals Mechanical Behavior of Damaged H-Section Steel Structure

2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Xibing Hu ◽  
Rui Chen ◽  
Yuxuan Xiang ◽  
Yafang Chen ◽  
Qingshan Li
Keyword(s):  
Cross Sections ◽  
Elastic Moduli ◽  
Mechanical Test ◽  
Steel Structure ◽  
Steel Structures ◽  
Computational Accuracy ◽  
Cross Sectional ◽  
Steel Columns ◽  
Steel Members ◽  
The Cross

Steel structures are usually damaged by disasters. According to the influence law of the damage on the elastic modulus of steel obtained by the mechanical test of damaged steel, the average elastic moduli of H-section steel members were analyzed. The equations for calculating the average elastic moduli of damaged H-section steel members at different damage degrees were obtained. By using the analytical cross-sectional method, the cross-sectional M-Φ-P relationships and the dimensionless parameter equations of the H-sections in the full-sectional elastic distribution, single-sided plastic distribution, and double-sided plastic distribution were derived. On the basis of the cross-sectional M-Φ-P relationships and dimensionless parameters of actual steel members, the approximate calculation equations for the damaged cross sections were obtained. The Newmark method was used to analyze the deformation of damaged steel columns. Analytical results show good agreement with the test results. The equations and methods proposed in this study have high computational accuracy, and these can be applied to the cross-sectional M-Φ-P relationships and deformation calculation of damaged steel members.

scholarly journals Experimental study on fatigue performance of Q420qD high-performance steel cross joint in complex environment

2021 ◽  
Author(s):  
Haigen Cheng ◽  
Cong Hu ◽  
Yong Jiang
Keyword(s):  
Fatigue Life ◽  
High Performance ◽  
Steel Structure ◽  
Steel Structures ◽  
Fatigue Tests ◽  
Fatigue Performance ◽  
Corrosive Media ◽  
Joint Connection ◽  
High Performance Steel ◽  
The Cross

AbstractThe steel structure under the action of alternating load for a long time is prone to fatigue failure and affects the safety of the engineering structure. For steel structures in complex environments such as corrosive media and fires, the remaining fatigue life is more difficult to predict theoretically. To this end, the article carried out fatigue tests on Q420qD high-performance steel cross joints under three different working conditions, established a 95% survival rate $$S{ - }N$$ S - N curves, and analyzed the effects of corrosive media and high fire temperatures on its fatigue performance. And refer to the current specifications to evaluate its fatigue performance. The results show that the fatigue performance of the cross joint connection is reduced under the influence of corrosive medium, and the fatigue performance of the cross joint connection is improved under the high temperature of fire. When the number of cycles is more than 200,000 times, the design curves of EN code, GBJ code, and GB code can better predict the fatigue life of cross joints without treatment, only corrosion treatment, and corrosion and fire treatment, and all have sufficient safety reserve.

Comparison of the Cross Sectional Area, the Loss in Volume and the Mechanical Properties of LAE442 and MgCa0.8 as Resorbable Magnesium Alloy Implants after 12 Months Implantation Duration

2010 ◽  
Vol 638-642 ◽  
pp. 675-680 ◽  
Author(s):  
Martina Thomann ◽  
Nina von der Höh ◽  
Dirk Bormann ◽  
Dina Rittershaus ◽  
C. Krause ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Cross Sections ◽  
Degradation Process ◽  
Cross Sectional Area ◽  
Bending Test ◽  
Sectional Area ◽  
Cross Sectional ◽  
Initial Strength ◽  
Three Point Bending ◽  
The Cross

Current research focuses on magnesium based alloys in the course of searching a resorbable osteosynthetic material which provides sufficient mechanical properties besides a good biocompatibility. Previous studies reported on a favorable biocompatibility of the alloys LAE442 and MgCa0.8. The present study compared the degradation process of cylindrical LAE442 and MgCa0.8 implants after 12 months implantation duration. Therefore, 10 extruded implants (2.5 x 25 mm, cross sectional area 4.9 mm²) of both alloys were implanted into the medullary cavity of both tibiae of rabbits for 12 months. After euthanization, the right bone-implant-compound was scanned in a µ-computed tomograph (µCT80, ScancoMedical) and nine uniformly distributed cross-sections of each implant were used to determine the residual implants´ cross sectional area (Software AxioVisionRelease 4.5, Zeiss). Left implants were taken out of the bone carefully. After weighing, a three-point bending test was carried out. LAE442 implants degraded obviously slower and more homogeneously than MgCa0.8. The mean residual cross sectional area of LAE442 implants was 4.7 ± 0.07 mm². MgCa0.8 showed an area of only 2.18 ± 1.03 mm². In contrast, the loss in volume of LAE442 pins was more obvious. They lost 64 % of their initial weight. The volume of MgCa0.8 reduced clearly to 54.4 % which corresponds to the cross sectional area results. Three point bending tests revealed that LAE442 showed a loss in strength of 71.2 % while MgCa0.8 lost 85.6 % of its initial strength. All results indicated that LAE442 implants degraded slowly, probably due to the formation of a very obvious degradation layer. Degradation of MgCa0.8 implants was far advanced.

scholarly journals Experimental Study on the Behavior of Tension Member Under Rupture

2021 ◽  
Keyword(s):  
Experimental Study ◽  
Tensile Force ◽  
Steel Structure ◽  
Steel Structures ◽  
Structural Members ◽  
Steel Members ◽  
Tension Member ◽  
Strong Relation ◽  
Almost All ◽  
Tension Members

Abstract. A steel structure is naturally lighter than a comparable concrete construction because of the higher strength and firmness of steel. Nowadays, the growth of steel structures in India is enormous. There are so many advantages in adopting the steel as structural members. Almost all high-rise buildings, warehouses & go-downs are steel structures and even some of the commercial buildings are made of steel. Tension members are the elements that are subjected to direct axial load which tends in the elongation of the structural members. Even today bolted connections play a major role in the connection of hot rolled structural steel members. In this experimental study the behavior of tension members (TM) such as plates, angles & channels have been studied under axial tensile force. There is strong relation between pitch and gauge (with in the specified limit as per IS 800:2007) in determining the rupture failure plane. In this study we intensively tested the behaviour of TM for different fasteners pattern by changing the pitch, gauge, end & edge distance and by adopting the different patterns or arrangements of bolted connection in it.

scholarly journals Supplemental Material: Plate boundary trench retreat and dextral shear drive intracontinental fault-slip histories: Neogene dextral faulting across the Gabbs Valley and Gillis Ranges, Central Walker Lane, Nevada

2020 ◽  
Author(s):  
J. Lee ◽  
et al.
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Plate Boundary ◽  
Fault Slip ◽  
Cross Sectional ◽  
Walker Lane ◽  
Dextral Shear ◽  
The Cross

<div>Figure 6. Interpretative cross sections illustrating the cross-sectional geometry of several paleovalleys. See Figure 3 for location of all cross sections and Figure 8 for location of cross section CCʹ. Cross sections AAʹ and BBʹ are plotted at the same scale, and cross section CCʹ is plotted at a smaller scale. Figure 6 is intended to be viewed at a width of 45.1 cm.</div>

The Optimization Design of the Cross-Sectional Layout of an Umbilical Based on the Hybrid Genetic Algorithm

2021 ◽  
Author(s):  
Xu Yin ◽  
Zhixun Yang ◽  
Dongyan Shi ◽  
Jun Yan ◽  
Lifu Wang ◽  
...  
Keyword(s):  
Genetic Algorithm ◽  
Cross Sections ◽  
Optimization Design ◽  
Mechanical Performance ◽  
Fitness Function ◽  
Hybrid Genetic Algorithm ◽  
Optimization Strategy ◽  
Cross Sectional ◽  
Great Probability ◽  
The Cross

Abstract The umbilical which consists of hydraulic tubes, electrical cables and optical cables is a key equipment in the subsea production system. Each components perform different physical properties, so different cross-sections will present different geometrical characteristic, carrying capacities, the cost and the ease of manufacture. Therefore, the cross-sectional layout design of the umbilical is a typical multi-objective optimization problem. A mathematical model of the cross-sectional layout considering geometric and mechanical properties is proposed, and the genetic algorithm is introduced to copy with the optimization model in this paper. A steepest descent operator is embedded into the basic genetic algorithm, while the appropriate fitness function and the selection operator are advanced. The optimization strategy of the cross-sectional layout based on the hybrid genetic algorithm is proposed with the fast convergence and the great probability for global optimization. Finally, the cross-section of an umbilical case is performed to obtain the optimal the cross-sectional layout. The geometric and mechanical performance of results are compared with the initial design, which verify the feasibility of the proposed algorithm.

The effect of crown position and tree age on resin-canal density in Scots pine (Pinus sylvestris L.) needles

2001 ◽  
Vol 79 (11) ◽  
pp. 1257-1261 ◽  
Author(s):  
Jinxing Lin ◽  
D A Sampson ◽  
R Ceulemans
Keyword(s):  
Pinus Sylvestris ◽  
Scots Pine ◽  
Cross Sections ◽  
Resin Canal ◽  
Tree Age ◽  
Needle Length ◽  
Cross Sectional ◽  
Crown Position ◽  
The Cross ◽  
Resin Canals

Resin canals are an important taxonomic characteristic in conifers. In this paper we examined within- and between-needle variation of the cross-sectional number of resin canals in Scots pine (Pinus sylvestris L.). Variation within needles was determined from 12 free-hand sections taken along the whole length of foliage collected from a common crown position. The effect of crown location and tree age on resin-canal density was also examined from the midpoint cross sections of 450 Scots pine needles collected from interior and exterior locations from the top, middle, and bottom of 25 crowns of trees ranging in age from 8 to 70 years. Within-needle resin-canal density varied with needle length. Two resin canals were typical for the basal and the terminal needle cross sections. There were 3.2 and 8.6 resin canals for cross sections taken from 10 and 30% of the needle length from the basal sheath, respectively. Resin-canal density was largest, and relatively constant, between 30 and 80% of the needle length. We found significant differences in the cross-sectional number of needle resin canals, as influenced by crown positions and tree age. Resin-canal density increased with foliage height. Foliage from the top one-third of crowns had significantly more resin canals than foliage from the bottom. Foliage collected from the crown interior (proximal to the stem) had fewer resin canals than samples from the crown edge. Resin-canal density increased from 7.1 to 10.3 as tree age increased from 8 to 70 years. These results suggest that crown position and tree age need to be incorporated into the sampling protocols used to establish species standards in resin-canal density, at least for Scots pine, if meaningful comparisons are to be made.Key words: resin canal, needle age, crown position, needle anatomy, Pinus sylvestris.

A self-locking steel bearing connection for circular reinforced concrete columns

2019 ◽  
Vol 22 (12) ◽  
pp. 2605-2619
Author(s):  
Denghu Jing ◽  
Shuangyin Cao ◽  
Theofanis Krevaikas ◽  
Jun Bian
Keyword(s):  
Reinforced Concrete ◽  
Cross Sections ◽  
Axial Loading ◽  
High Strength ◽  
Axial Stiffness ◽  
Concrete Column ◽  
Reinforced Concrete Column ◽  
Cross Sectional ◽  
Locking Mechanism ◽  
The Cross

This article proposes a new connection between a steel bearing and a reinforced concrete column, which is mainly used for provisionally providing jack support in existing reinforced concrete structures. In this suggested connection joint, the steel bearing consisted of two or four symmetrical components assembled by high-strength bolts, which surrounds the reinforced concrete column by a tapered tube and balances the vertical load via the friction force between the tapered tube and concrete, that is, through a self-locking mechanism. The proposed connection joint can be assembled easily at a construction site and can also be disassembled and reused many times. To demonstrate the feasibility of this type of connection joint, a simple test was conducted to illustrate the concept, that is, a total of four medium-scale steel bearing–reinforced concrete column connections with circular cross sections were fabricated and tested under axial loading. The test results showed that the steel bearing–reinforced concrete column connection based on self-locking mechanism exhibited good working performance. Furthermore, a simplified formula to predict the axial stiffness of the connection joint was presented. From the tests and the proposed formula, the most important factors that influence the axial stiffness of this type of connection joint on the premise of an elastic working state are the slope of the tapered tube, the height of the steel bearing, the thickness of the tapered tube, the cross section of the reinforced concrete column, the cross-sectional area of all the connecting bolts, the proportion of the number of top bolts, the area of the top ring plate, and the effective contact area ratio.

Interference in a three-dimensional array of jets

2015 ◽  
Vol 26 (5) ◽  
pp. 795-819
Author(s):  
P. E. WESTWOOD ◽  
F. T. SMITH
Keyword(s):  
Cross Sections ◽  
Flow Direction ◽  
Three Dimensional ◽  
Cross Flow ◽  
Longitudinal Vortex ◽  
Cross Sectional ◽  
Dimensional Array ◽  
Unsteady Jets ◽  
The Cross ◽  
Jet Cross Sections

The theoretical investigation here of a three-dimensional array of jets of fluid (air guns) and their interference is motivated by applications to the food sorting industry especially. Three-dimensional motion without symmetry is addressed for arbitrary jet cross-sections and incident velocity profiles. Asymptotic analysis based on the comparatively long axial length scale of the configuration leads to a reduced longitudinal vortex system providing a slender flow model for the complete array response. Analytical and numerical studies, along with comparisons and asymptotic limits or checks, are presented for various cross-sectional shapes of nozzle and velocity inputs. The influences of swirl and of unsteady jets are examined. Substantial cross-flows are found to occur due to the interference. The flow solution is non-periodic in the cross-plane even if the nozzle array itself is periodic. The analysis shows that in general the bulk of the three-dimensional motion can be described simply in a cross-plane problem but the induced flow in the cross-plane is sensitively controlled by edge effects and incident conditions, a feature which applies to any of the array configurations examined. Interference readily alters the cross-flow direction and misdirects the jets. Design considerations centre on target positioning and jet swirling.

scholarly journals Analytical description of nanowires. I. Regular cross sections for zincblende and diamond structures

2019 ◽  
Vol 75 (5) ◽  
pp. 788-802 ◽  
Author(s):  
Dirk König ◽  
Sean C. Smith
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Analytical Description ◽  
Data Interpretation ◽  
High Symmetry ◽  
Cross Sectional ◽  
Impurity Atoms ◽  
Si Nanocrystals ◽  
Impurity Doping ◽  
The Cross

Semiconductor nanowires (NWires) experience stress and charge transfer from their environment and impurity atoms. In response, the environment of a NWire experiences a NWire stress response which may lead to propagated strain and a change in the shape and size of the NWire cross section. Here, geometric number series are deduced for zincblende- (zb-) and diamond-structured NWires of diameter d Wire to obtain the numbers of NWire atoms N Wire(d Wire[i]), bonds between NWire atoms N bnd(d Wire[i]) and interface bonds N IF(d Wire[i]) for six high-symmetry zb NWires with the low-index faceting that occurs frequently in both bottom-up and top-down approaches of NWire processing. Along with these primary parameters, the specific lengths of interface facets, the cross-sectional widths and heights and the cross-sectional areas are presented. The fundamental insights into NWire structures revealed here offer a universal gauge and thus could enable major advancements in data interpretation and understanding of all zb- and diamond-structure-based NWires. This statement is underpinned with results from the literature on cross-section images from III–V core–shell NWire growth and on Si NWires undergoing self-limiting oxidation and etching. The massive breakdown of impurity doping due to self-purification is shown to occur for both Si NWires and Si nanocrystals (NCs) for a ratio of N bnd/N Wire = N bnd/N NC = 1.94 ± 0.01 using published experimental data.

Optimization Design of the Cross-Section of the Umbilical Based on the Pseudo Mechanical Mechanism

2020 ◽  
Author(s):  
Zhixun Yang ◽  
Xu Yin ◽  
Dongyan Shi ◽  
Jun Yan ◽  
Lifu Wang ◽  
...  
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Optimization Design ◽  
Signal Transmission ◽  
Interaction Force ◽  
Steel Tube ◽  
Iteration Algorithm ◽  
Cross Sectional ◽  
The Cross ◽  
Electrical Cables

Abstract Umbilical is a critical equipment in subsea production system for extracting offshore hydrocarbon resources, providing electrical and hydraulic power, control signal transmission and chemical injection. A diversity of components such as electrical cables, optical cables, steel tubes and filler bodies compose the cross-section of an umbilical. Different components perform different physical properties, so different cross-sections will present different geometrical characteristic, carrying capacities, thermal distribution, the cost and the ease of manufacture. Therefore, the cross-sectional design of the umbilical is a typical multi-objective optimization problem. The methodology of pseudo mechanical mechanism is introduced in this paper. Pseudo forces are assumed based on geometrical characteristics, carrying capacities and thermal productivities of different electrical cables, optical cables, steel tube and filler bodies. Each component is analogized to a sphere with different diameters on a funnel surface. Moreover, potential energy and interaction force between different components are defined to avoid the overlap and congestion. Then, the pseudo mechanical model is established and mathematics description is presented corresponding to the cross-section of an umbilical. Iteration algorithm procedure is given to solve this problem. Finally, a case of an umbilical is studied and the optimal cross-section is obtained, which is compared with the result used in practical engineering. It is shown that the methodology of the pseudo mechanical mechanism is effective to obtain the optimal design of cross-section of an umbilical.

Sign in / Sign up

Export Citation Format

Share Document