Effects of Connecting Plates on Cold-Formed Steel Wall Plate System

2016 ◽  
Vol 858 ◽  
pp. 38-43
Author(s):  
Ng Ling Ying Adeline ◽  
Wei Hui Hii
Keyword(s):  
Failure Mode ◽  
Material Properties ◽  
Experimental Investigations ◽  
Ultimate Capacity ◽  
Pull Out ◽  
Modes Of Failure ◽  
Cold Formed Steel ◽  
Yield Capacity ◽  
Mode Failure ◽  
Plate System

The paper presents experimental investigations on cold-formed steel (CFS) wall plate system. The behavior and the modes of failure of the system under uplift were studied. The parameters tested were the presence of gaps and the thickness of connecting plates. Results showed that samples with and without gaps at the supports experienced the same failure mode. Failure began with the yielding of connecting plates followed by the buckling of C-channel. Similar ultimate capacity was also obtained for samples with and without gaps. When connecting plates of different thicknesses were used to connect the wall-plate, different modes of failure were observed. Instead of yielding in the connecting plates, screw pull-out was observed in the connection before the C-channel buckled. Besides, it was observed that the ultimate capacity of the system was reduced when thicker connecting plates were used. It is not conservative to estimate the capacity of screwed connection according to the design standard and it is proposed that the capacity of the wall plate system is taken as the yield capacity of the connecting plates of the same material properties.

Effect of temperature and galvanization on the compressive strength of cold-formed angles

1990 ◽  
Vol 17 (3) ◽  
pp. 440-451 ◽  
Author(s):  
D. Polyzois ◽  
P. Charnvarnichborikarn ◽  
S. Rizkalla ◽  
C. K. Wong
Keyword(s):  
Compressive Strength ◽  
Material Properties ◽  
Room Temperature ◽  
Slenderness Ratio ◽  
Effect Of Temperature ◽  
Experimental Program ◽  
Ultimate Capacity ◽  
Cold Formed Steel ◽  
University Of Manitoba ◽  
The University

An experimental program was conducted at The University of Manitoba to investigate the effect of subfreezing temperatures and galvanization on the compressive strength of cold-formed steel angles. The study involved the testing of 20 cold-formed angles, 55 × 55 × 4 mm, with a slenderness ratio of approximately 70. Equal numbers of galvanized and ungalvanized angles were tested at various temperatures ranging from −45 to 25 °C. The material properties were obtained through 48 standard tension coupon tests conducted at the same temperature range. The results showed that the capacity of the angles measured at temperatures below −40 °C was approximately 8% higher than the capacity at room temperature. Similar results were obtained during testing of the standard tension coupons where the yield and tensile strengths of the steel used were approximately 10% higher at temperatures below −40 °C than at room temperature. On the average, the ultimate capacity of galvanized angles was approximately 9% higher than that of ungalvanized angles. Although the yield strength of the corner coupons was between 13% and 27% higher than that of flat coupons tested at room temperature, the compressive strength of the full-size angles was influenced mainly by the material properties of the flat regions. A comparison of the measured and predicted capacities using the current Canadian standard and American specification indicated that the Canadian standard overestimated the ultimate capacity of the angles by as much as 37%, while the American specification underestimated the capacity by as much as 45%. Key words: angles, cold-formed, galvanized, temperature, compression, ultimate.

scholarly journals Investigation on Flexural Behaviour of Cold Formed Steel Latticed Built-Up I Section with Drop Web

2018 ◽  
Vol 7 (1) ◽  
pp. 65-68
Author(s):  
N. Nandhini . ◽  
K. Sudha .
Keyword(s):  
Numerical Analysis ◽  
Cost Effective ◽  
Ultimate Capacity ◽  
Flexural Behaviour ◽  
Modes Of Failure ◽  
Finite Element Procedure ◽  
Cold Formed Steel ◽  
Experimental Works ◽  
Numerical Finite Element ◽  
Design Proposal

This paper deals with the study of flexural behaviour of cold formed latticed built-up I beam with drop web for various sections by varying depth, thickness and span length of the section. The numerical analysis was carried out by FEM software ABAQUS 6.13[11]. The experimental works carried out by Cheng Yu and Benjamin W. Schafer (2006) [1] were taken for validating the numerical analysis procedure. It provides a cost effective way to explore the performance of products in a virtual environment. The ultimate capacity is obtained by performing both linear and non-linear analysis. Theoretical investigation as per AISI specification was carried out for all the specimens to check the accuracy of the design proposal. Numerical finite element procedure is used to instruct the effect of various parameters on behavior of beams. The critical load and different modes of failure are studied by this numerical investigation. Comparison between deformed shape and load vs. displacement curves of I section with drop web were presented.

scholarly journals A FEM-Based 2D Model for Simulation and Qualitative Assessment of Shot-Peening Processes

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 2784
Author(s):  
Georgios Maliaris ◽  
Christos Gakias ◽  
Michail Malikoutsakis ◽  
Georgios Savaidis
Keyword(s):  
Process Parameters ◽  
Material Properties ◽  
Shot Peening ◽  
Qualitative Assessment ◽  
Experimental Investigations ◽  
Elastoplastic Material ◽  
Size Distributions ◽  
User Friendly ◽  
The Impact ◽  
2D Model

Shot peening is one of the most favored surface treatment processes mostly applied on large-scale engineering components to enhance their fatigue performance. Due to the stochastic nature and the mutual interactions of process parameters and the partially contradictory effects caused on the component’s surface (increase in residual stress, work-hardening, and increase in roughness), there is demand for capable and user-friendly simulation models to support the responsible engineers in developing optimal shot-peening processes. The present paper contains a user-friendly Finite Element Method-based 2D model covering all major process parameters. Its novelty and scientific breakthrough lie in its capability to consider various size distributions and elastoplastic material properties of the shots. Therewith, the model is capable to provide insight into the influence of every individual process parameter and their interactions. Despite certain restrictions arising from its 2D nature, the model can be accurately applied for qualitative or comparative studies and processes’ assessments to select the most promising one(s) for the further experimental investigations. The model is applied to a high-strength steel grade used for automotive leaf springs considering real shot size distributions. The results reveal that the increase in shot velocity and the impact angle increase the extent of the residual stresses but also the surface roughness. The usage of elastoplastic material properties for the shots has been proved crucial to obtain physically reasonable results regarding the component’s behavior.

Failure Modes of Tapered Suction Caissons Under Vertical Pull-Out Loads

2007 ◽  
Author(s):  
Mahmood Nabipour ◽  
Mostafa Zeinoddini ◽  
Mahmood R. Abdi
Keyword(s):  
Failure Modes ◽  
Numerical Approach ◽  
Local Failure ◽  
Superior Performance ◽  
Soil Plug ◽  
Pull Out ◽  
Modes Of Failure ◽  
Numerical Studies ◽  
Second Mode ◽  
Suction Caissons

The pull-out performance of conventional upright suction caissons has been investigated by different researchers. However, no attention has been formerly paid to tapered suction caissons. Some numerical studies already conducted by the authors demonstrated that tapered caissons exhibit pull-out capacities well above than that from their corresponding upright caissons. This paper deals with different failure mechanisms of tapered suction caissons and discusses some reason for their superior performance. A numerical approach has been used and different combinations of caisson types/ soil categories have been examined. With tapered suction caissons two different modes of failure have been discerned. The first mode has been noticed to develop in weak clays and sands under drained conditions. This mode corresponds to a shear sliding failure in the soil plug along the caisson’s interior wall. Concurrently a soil wedge is formed in the soil body adjacent to the caisson. The second mode of failure has been observed in higher strength drained clays and undrained clays and sands. With this failure mode a local failure at the bottom of the soil plug has been noticed to happen. At the same time the failure is extended to the lower surfaces of a soil wedge outside of the caisson. The detached soil plug accompanies the caisson in its movement upward following the local failure.

scholarly journals Strength of RC Beam using Geopolymer Concrete and Adopting Bubble Technology

2021 ◽  
Vol 9 (VI) ◽  
pp. 2812-2816
Author(s):  
Abhinay I. Deshmukh
Keyword(s):  
Hollow Spheres ◽  
Experimental Investigations ◽  
Geopolymer Concrete ◽  
Tension Zone ◽  
Portland Cement Concrete ◽  
Dead Weight ◽  
Conventional Concrete ◽  
Modes Of Failure ◽  
Calcium Silicate Hydrates ◽  
Load Carrying

The Bubble Deck technology developed in Europe makes use of high-density polyethylene hollow spheres to replace the ineffective concrete in the centre of the slab, thus decreasing the dead weight and increasing the efficiency of the floor. Concrete is good in compression and hence is more useful in the compression region than in the tension region. The reduction in concrete can be done by replacing the tension zone concrete. Keeping the same idea in mind, an attempt has been made to find out the effectiveness of plastic bubbles by replacing concrete in the tension zone of Ordinary Portland Cement Concrete (OPCC) and Geopolymer Concrete (GPC) beam. Geopolymer Concrete does not form calcium- silicate-hydrates (CSHs) for matrix formation and strength like OPCC but utilizes the polycondensation of silica and alumina precursors to attain structural strength. In this project, M25 concrete mix is used to prepare both OPCC and GPC beams. The trial mix is tested for compressive strength. Flexure test is done is done for 28 days of curing of the beams. This paper presents the results of the experimental investigations carried out to determine and to compare the flexural behaviour of geopolymer concrete (GPC) beams with conventional concrete beams of same grade. The beams were tested under two point monotonic loading. Performance aspects such as load carrying capacity, first crack load, ultimate load, load-deflection behaviour, moment-curvature behaviour, crack width, crack spacing and the modes of failure of both types of beams were studied. The test results showed that the geopolymer concrete exhibits better performance compared to conventional concrete of same grade.

scholarly journals Microstructure and mechanical properties of an ultrasonic spot welded aluminum alloy: the effect of welding energy

2021 ◽  
Author(s):  
He Peng ◽  
Daolun Chen ◽  
Xianquan Jiang
Keyword(s):  
Shear Strength ◽  
Aluminum Alloy ◽  
Cyclic Loading ◽  
Crack Growth ◽  
Failure Mode ◽  
Spot Welding ◽  
Energy Levels ◽  
Lap Shear Strength ◽  
Pull Out ◽  
Lap Shear

The aim of this study is to evaluate the microstructures, tensile lap shear strength, and fatigue resistance of 6022-T43 aluminum alloy joints welded via a solid-state welding technique–ultrasonic spot welding (USW)–at different energy levels. An ultra-fine necklace-like equiaxed grain structure is observed along the weld line due to the occurrence of dynamic crystallization, with smaller grain sizes at lower levels of welding energy. The tensile lap shear strength, failure energy, and critical stress intensity of the welded joints first increase, reach their maximum values, and then decrease with increasing welding energy. The tensile lap shear failure mode changes from interfacial fracture at lower energy levels, to nugget pull-out at intermediate optimal energy levels, and to transverse through-thickness (TTT) crack growth at higher energy levels. The fatigue life is longer for the joints welded at an energy of 1400 J than 2000 J at higher cyclic loading levels. The fatigue failure mode changes from nugget pull-out to TTT crack growth with decreasing cyclic loading for the joints welded at 1400 J, while TTT crack growth mode remains at all cyclic loading levels for the joints welded at 2000 J. Fatigue crack basically initiates from the nugget edge, and propagates with “river-flow” patterns and characteristic fatigue striations. Keywords: aluminum alloy; ultrasonic spot welding; EBSD; microstructure; tensile strength; fatigue

Clamped torispherical shells under external pressure — some new results

1988 ◽  
Vol 23 (1) ◽  
pp. 9-24 ◽  
Author(s):  
J Blachut ◽  
G D Galletly
Keyword(s):  
Failure Mode ◽  
External Pressure ◽  
Spherical Cap ◽  
Geometric Imperfections ◽  
Collapse Pressure ◽  
Modes Of Failure ◽  
Shell Buckling ◽  
Bifurcation Buckling ◽  
Initial Geometric Imperfections ◽  
The One

Perfect clamped torispherical shells subjected to external pressure are analysed in the paper using the BOSOR 5 shell buckling program. Various values of the knuckle radius-to-diameter ratio ( r/D) and the spherical cap radius-to-thickness ratio ( Rs/ t) were studied, as well as four values of σyp, the yield point of the material. Buckling/collapse pressures, modes of failure and the development of plastic zones in the shell wall were determined. A simple diagram is presented which enables the failure mode in these shells to be predicted. The collapse pressures, pc, were also plotted against the parameter Λs (√( pyp/ pcr)). When the controlling failure mode was axisymmetric yielding in the knuckle, the collapse pressure curves depended on the value of σyp, which is unusual. However, when the controlling failure mode was bifurcation buckling (at the crown/knuckle junction), the collapse pressure curves for the various values of σyp all merged, i.e., they were independent of σyp. This latter situation is the one which normally occurs with the buckling of cylindrical and hemispherical shells. A limited investigation was also made into the effects of axisymmetric initial geometric imperfections on the strength of externally-pressurised torispherical shells. When the failure mode was axisymmetric yielding in the knuckle, initial imperfections of moderate size did not affect the collapse pressures. In the cases where bifurcation buckling at the crown/knuckle junction occurred, small initial geometric imperfections at the apex did not affect the buckling pressure, but axisymmetric imperfections at the buckle location did influence it. With the other failure mode (i.e., axisymmetric yielding collapse at the crown of the shell), initial geometric imperfections caused a reduction in the torisphere's strength.

Experimental Investigations on Spot Welded Built-Up Cold-Formed Steel Beams

2018 ◽  
Vol 1146 ◽  
pp. 142-151
Author(s):  
Viorel Ungureanu ◽  
Ioan Both ◽  
Mircea Burca ◽  
Ştefan Benzar ◽  
Thai Hoang Nguyen ◽  
...  
Keyword(s):  
Spot Welding ◽  
Steel Sheet ◽  
Experimental Program ◽  
Experimental Investigations ◽  
Steel Beams ◽  
Technological Solution ◽  
Research Project ◽  
Steel Sheets ◽  
Cold Formed Steel ◽  
Thin Walled

Within the WELLFORMED research project, ongoing at the CEMSIG Research Center of the Politehnica University of Timisoara, a new technological solution was proposed for built-up beams made of corrugated steel sheets for the web and thin-walled cold-formed steel profiles for the flanges, connected by spot welding. The research project integrates an extensive experimental program on such beams, using full scale specimens, to demonstrate the feasibility of the proposed solutions and to assess their performance, followed by numerical simulations to characterize and optimize the connecting details. The present paper presents the results of a large experimental program, on small specimens subjected to shear, consisting of two or three layers of steel sheet connected by spot welding.

scholarly journals Experimental Study on the Effect of Heel Plate Length on the Structural Integrity of Cold-formed Steel Roof Trusses

2018 ◽  
Vol 65 ◽  
pp. 08010
Author(s):  
Je Chenn Gan ◽  
Jee Hock Lim ◽  
Siong Kang Lim ◽  
Horng Sheng Lin
Keyword(s):  
Ultimate Load ◽  
Structural Integrity ◽  
Load Capacity ◽  
Local Buckling ◽  
Ultimate Capacity ◽  
Ultimate Load Capacity ◽  
Plate Length ◽  
Roof Truss ◽  
Cold Formed Steel ◽  
Structural Failures

Applications of Cold-Formed Steel (CFS) are widely used in buildings, machinery and etc. Many researchers began the research of CFS as a roof truss system. It is required to increase the knowledge of the configurations of CFS roof trusses due to the uncertainty of the structural failures regarding the materials and rigidity of joints. The objective of this research is to investigate the effect of heel plate length to the ultimate load capacity of CFS roof truss system. Three different lengths of heel plate specimens were fabricated and subjected to concentrated loads until failure. The highest ultimate capacity for the experiment was 30 kN. The results showed that the increment of the length of the heel plate had slightly increased the ultimate capacity and strain. The increment of the length of the heel plate had increased the deflection of the bottom chords but decreased the deflection of the top chords. Local buckling of top chords adjacent to the heel plate was the primary failure mode for all the heel plate specimens.

scholarly journals Fatigue Behaviors of Resistance Spot Welds for 980 MPa Grade TRIP Steel

Metals ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 1086
Author(s):  
Heewon Cho ◽  
Sangwoo Nam ◽  
Insung Hwang ◽  
Je Hoon Oh ◽  
Munjin Kang ◽  
...  
Keyword(s):  
Fatigue Life ◽  
Failure Mode ◽  
Trip Steel ◽  
Failure Modes ◽  
Propagation Speed ◽  
Outer Edge ◽  
Fatigue Load ◽  
Resistance Spot ◽  
Fracture Surfaces ◽  
Pull Out

The fatigue life of the resistance spot weld of 980 MPa grade transformation induced plasticity (TRIP) steel was investigated and failure modes and fracture surfaces according to the fatigue load were analyzed. The fatigue life according to the nugget size was observed by using two electrodes with face diameters of 8 mm and 10 mm. When an electrode face diameter with 10 mm was used, the nugget size was large, and the fatigue life was further increased. After the fatigue test, three types of failure modes were observed, namely pull-out, plug, and heat affected zone (HAZ) failure, depending on the fatigue load. The fracture surfaces in each failure mode were analyzed. In all failure modes, a crack was initiated in the HAZ region, which is the interface between the two materials in all failure modes. In the case of pull-out failure, the crack propagates as if it surrounds the nugget at the outer edge of the nugget. In the case of HAZ failure, the crack propagates in the thickness direction of the material and outward in the nugget shell. Plug failure occurs with pull-out failure and HAZ failure mixed. The propagation patterns of cracks were different for each failure mode. The reason why the failure mode and the fracture surface are different according to the fatigue load is that the propagation speed of the fatigue crack is fast when the fatigue load is relatively large and is slow when the fatigue load is low.

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