scholarly journals Structural Performance of Thin-Walled Twisted Box-Section Structure

Buildings ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 12
Author(s):  
Shijun Wang ◽  
Zan Wang ◽  
Chang Ping ◽  
Xing Wang ◽  
Huiying Wu ◽  
...  

The light weight and high strength-to-mass ratio of thin-walled boxed sections have incited interest in their widespread use in the construction of domes. However, the installation of these sections in forming the dome geometry has induced initial twists and curving features, to which their mechanical response has rarely been explored. Therefore, the structural performance of a structure with thin-walled twisted box sections is numerically studied in this paper, employing ANSYS, the verification of which is carried out through a comparison with experimental results. Additional components examined include the longitudinal stiffening rib, diaphragm, and web. The effects of variations in the thicknesses of these member plates on the mechanical behaviors are investigated. In general, the ultimate capacity of the structure is improved by increasing the thickness of the longitudinal stiffening rib, diaphragm, and web, but the strengthening effect of the stiffener is limited by a certain thickness enhancement. The common failure mode of the initial model is found to be an overall elastic-plastic buckling. A reduction in the thickness of the stiffener or web creates a curving deformation zone in the lower arch at the ultimate capacity, whereas the diaphragm thickness has little effect on the failure mode of the model.

2012 ◽  
Vol 446-449 ◽  
pp. 180-185
Author(s):  
Ng Ling Ying Adeline ◽  
Mei Chee Chiang

The paper presents an experimental investigation on the structural performance of high strength cold-formed steel angle connection stiffened with U-bracket. A total of 18 sets of specimens were tested using different U-bracket configurations. The parameters of the U-bracket studied were the width of the web and the length of the flanges. The behaviour of the connection under load was observed and the failure mode of the connection was identified. It was shown that biaxial deformation occurred in the U-bracket. It was also demonstrated that the capacity of the connection of angle and U-bracket was 4 times the capacity of plain angles. Results showed that it was more conservative to estimate the strength of the connection by taking the total elastic capacity of the sections. It was more effective to use U-bracket with a 40mm web and 15mm long flanges with the 50mm width angle connection.


Author(s):  
Carmen Ibáñez Usach ◽  
David Hernández-Figueirido ◽  
Ana Piquer Vicent

In order to study the mechanical response of concrete-filled steel tubular (CFST) columns, several experimental and theoretical studies have been conducted in the last years. However, the influence of thin-walled steel tubes on the axial capacity of these composite columns is not completely stablished, especially when it is combined with high-strength concrete as infill. In this paper, the results of an experimental campaign on 9 concrete-filled steel tubular stub columns subjected to concentric load are presented. Different cross-section shapes are considered in this campaign, i.e. circular, square and rectangular. The influence of the steel tube wall thickness is analysed by including in the tests specimens with thin-walled tubes, whose behaviour needs to be studied in depth given the issues arising when working under compression. The experimental program is designed so the analysis of the results permits to drawn consistent conclusions. For each series, the steel tube thickness is the only geometric parameter modified in order to properly study its effect. Besides, two different concrete strengths were considered for the concrete infill, i.e. normal and high- strength concrete, to observe their effect on the ultimate capacity of the columns. During the tests, the specimens are subjected to axial load and the evolution of the axial displacement with the load is registered. The ultimate capacity of each specimen is obtained and an analysis of the steel tube thickness and concrete strength influence is accomplished. Finally, the study of the dependency of the failure mode on these parameters is carried out.


Author(s):  
Marco Marini ◽  
Michela Talò ◽  
Giulia Lanzara ◽  
Walter Lacarbonara

Abstract Carbon nanotubes (CNT) represent an effective filler to be incorporated into polymer matrices. Their physical properties allow them to exert a remarkable strengthening effect, while their nano-scale leaves the polymer weight unaltered. Exploiting their high strength-to-weight ratio, CNT/polymer nanocomposites appear to be the ideal materials to be shaped as wires and fibers. In this work, an ad-hoc innovative extrusion process is proposed to fabricate though and ultralong CNT/polymer nanocomposite wires. The process parameters are finely tuned to produce nanocomposite filaments exhibiting optimized mechanical properties. Optical analyses validate the morphological features of the fabricated filaments having an averaged diameter of 350 μm. Monotonic tensile tests are carried out to investigate the mechanical response of wires with CNTs content ranging from 1 wt% to 3 wt%. Young’s modulus and tensile strength registered increments of 47% and 43%, respectively, when comparing the 3 wt% CNT nanocomposite wires with the neat polymer wires. Finally, cyclic tensile tests are employed to investigate the change in damping capacity that accompanies the integration of CNTs into the polymer matrix. Such optimized CNTs nanocomposite wires can be easily integrated into several devices or assembled into ropes and yarns with multifunctional, improved properties.


Alloy Digest ◽  
1976 ◽  
Vol 25 (1) ◽  

Abstract ATLANTIC 13B Alloy is a silicon bronze casting alloy offering excellent castability and corrosion resistance, good machinability and medium-high strength. It is an all-purpose alloy that is suitable for gears, valve parts and marine fittings. It is especially useful in stress-corrosion environments for thin-walled parts. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties as well as fracture toughness and fatigue. It also includes information on corrosion resistance as well as casting, heat treating, machining, and joining. Filing Code: Cu-307. Producer or source: Atlantic Casting and Engineering Corporation.


Alloy Digest ◽  
2017 ◽  
Vol 66 (7) ◽  

Abstract Strenx Section 900 is a cold-formed steel section made of hot-rolled, high-strength steel with a minimum yield strength of 900 MPa (131 ksi). Its high strength combined with naturally stiff form enables construction of stronger and lighter structures. The common shape is a U-bend channel. This datasheet provides information on composition, physical properties, tensile properties, and bend strength as well as fracture toughness. It also includes information on forming, machining, and joining. Filing Code: SA-792. Producer or source: SSAB Swedish Steel Inc..


Alloy Digest ◽  
1977 ◽  
Vol 26 (10) ◽  

Abstract ZA-27 is a zinc-aluminum-copper alloy that offers exceptionally high strength (58,000 to 64,000 psi tensile strength as cast) at modest cost. It performs best in thin-walled castings (down to 0.10 inch) which means reduced weight and lower material costs when castings are redesigned. It is similar to the general-purpose ZA-12 alloy (Alloy Digest Zn-31, September 1977) except for its higher strength and elongation, but with higher casting temperatures and poor heavy-section castability. This datasheet provides information on composition, physical properties, hardness, tensile properties, and shear strength as well as fracture toughness and creep. It also includes information on corrosion and wear resistance as well as casting, forming, heat treating, machining, and surface treatment. Filing Code: Zn-32. Producer or source: Eastern Alloys Inc.. See also Alloy Digest Zn-50, June 1990.


Author(s):  
Bhanu P. Sood ◽  
Michael Pecht ◽  
John Miker ◽  
Tom Wanek

Abstract Schottky diodes are semiconductor switching devices with low forward voltage drops and very fast switching speeds. This paper provides an overview of the common failure modes in Schottky diodes and corresponding failure mechanisms associated with each failure mode. Results of material level evaluation on diodes and packages as well as manufacturing and assembly processes are analyzed to identify a set of possible failure sites with associated failure modes, mechanisms, and causes. A case study is then presented to illustrate the application of a systematic FMMEA methodology to the analysis of a specific failure in a Schottky diode package.


Author(s):  
Haolei Mou ◽  
Zhenyu Feng ◽  
Jiang Xie ◽  
Jun Zou ◽  
Kun Zhou

AbstractTo analysis the failure and energy absorption of carbon fiber reinforced polymer (CFRP) thin-walled square tube, the quasi-static axial compression loading tests are conducted for [±45]3s square tube, and the square tube after test is scanned to further investigate the failure mechanism. Three different finite element models, i.e. single-layer shell model, multi-layer shell model and stacked shell mode, are developed by using the Puck 2000 matrix failure criterion and Yamada Sun fiber failure criterion, and three models are verified and compared according to the experimental energy absorption metrics. The experimental and simulation results show that the failure mode of [±45]3s square tube is the local buckling failure mode, and the energy are absorbed mainly by intralaminar and interlaminar delamination, fiber elastic deformation, fiber debonding and fracture, matrix deformation cracking and longitudinal crack propagation. Three different finite element models can reproduce the collapse behaviours of [±45]3s square tube to some extent, but the stacked shell model can better reproduce the failure mode, and the difference of specific energy absorption (SEA) is minimum, which shows the numerical simulation results are in better agreement with the test results.


Sign in / Sign up

Export Citation Format

Share Document