Joints Of Steel Plates Research Articles

Investigating corrosion-induced deterioration in bolted steel plate joints using guided wave ultrasonic inspection

AbstractBolted steel plate joints encounter challenges posed by joint corrosion, which impact the quality of interfacial contact among the bolted components. Unfortunately, no correlation between corrosion-induced joint damage and preload, nor an existing numerical model capable of capturing such effects, has been identified. This study aims to utilize guided wave ultrasonic investigation to examine the deterioration of interfacial contact caused by corrosion in bolted joints. Additionally, a contact modification-based numerical approach is presented to capture the effects of changing interfacial stress during joint corrosion. Guided wave mode selection was conducted with some preliminary experiments supplemented with the theory of wave mode dispersion, hence leading to the selection of S0 and A0 mode existing at 300 kHz. The joint was then corroded in a controlled manner using an electrochemical process while simultaneous ultrasonic measurements were taken. The experimental observations highlighted the progressive dispersion in the transmitted A0 mode across the bolted joint, potentially due to changing interfacial stress boundaries between the plates. A damage parameter, termed the dispersion index, was developed based on the energy ratio of different signal sections. A linear change in the dispersion index was observed with the increase in corrosion-induced mass loss. The insight was further established through a numerical investigation by studying the effect of changing bolt preload and the corresponding interfacial stress distribution. The findings revealed that monitoring the changes in the stress distribution at the bolted interface can provide insight into interfacial corrosion. Eventually, destructive tension test results confirmed the effect of joint corrosion on the load-bearing capacity of the joint. The change in failure mode of the pristine and corroded specimen is observed. The reported approach establishes the potential of ultrasonic inspection to investigate the interfacial health of a bolted joint in corroding conditions.

Flexural behavior of precast concrete beams in-span assembled with bolt-steel plate joints

The assembly of precast concrete structural components is primarily concentrated at the splicing joints of the components. Wet connections involving additional stirrups and detailing cause casting difficulties and possibly deficient joints. Herein, a new type of precast beam in-span assembled with bolt–steel plate joints (PBSPB) is proposed. A significant unique feature is the discontinuous longitudinal reinforcement in the midspan, where the U-shaped steel plate covers the web and tensile zone of the concrete beam. The steel plates and bolts are used to connect the two assembled short beams to resist both flexure and shear owing to the external effects. To investigate the effects of the steel-plate thickness and span–depth ratio on the flexural behavior of beams, a static behavior test was conducted on six PBSPBs and one cast-in-situ beam. The failure mechanisms of the PBSPBs and cast-in-situ beam were examined and compared with regard to the crack propagation, load–displacement characteristics, and strain responses. All the PBSPBs exhibited excellent performance with limited cracks under identical conditions; only minor damage was observed, which consisted of small amounts of concrete spalling and edge warping of the steel plates. Finite-element analysis (ABAQUS) models of the proposed PBSPBs were developed to verify the ultimate load and damage situations of each specimen, a simplified flexural-capacity calculation formula for the PBSPB was developed, and the theoretical results were consistent with the experimental results. The results indicated that the new precast concrete beams had favorable flexural capacities. The beam with thicker steel plates in the span had a higher strength owing to the higher stiffness. Increasing the span–depth ratio increased the ultimate load and barely affected the failure mechanism.

Evaluation of Welding Distortion and Hardness in the A36 Steel Plate Joints Using Different Cooling Media

The temperature difference in the weld area during the process of welding, cooling the welded product, and post-welding affect the formation of distortion. Therefore, this study aims to evaluate the distortion formed and hardness behavior on the ASTM A36 (EN S275) steel plate while welding using different cooling media including air, water, and ice. This involved using the MAG (Metal Active Gas) method, which used the AWS A5.18 ER70S-6 electrode with a 1 mm diameter and an 8 mm plate thickness. The value of distortion on the MAG-welded steel plate was measured using a digital dial indicator and evenly distributed by first making a grid. Moreover, the measuring points from the transverse and longitudinal directions were placed at 20 and 8 rows with a distance of 10 mm between points for each variation of the cooling media, such that 10 mm each was allowed left-right and top-down. The results showed that the highest distortion value of 3.13 was formed on the second row of the air cooling media, and this media was also used to determine the contours and distortion profiles.

X-RAY RADIOGRAPHIC ANALYSIS OF AISI 304 STEEL STEEL JOINTS RESULTS ON TUNGSTEN INERT GAS WELDING WITH CURRENT 40 – 60 AMPERES

X-Ray Radiographic Analysis of Aisi 304 Stainless Steel Plate Joints From Inert Gas Tungsten Welding Results with 40 – 60 Ampere Current. Metal welding process is one of the main processes in machine construction. The quality of welded joints determines the strength and toughness of a machine construction. The quality of welded joints of installed construction can be determined by the non-destructive test method using X-ray radiography equipment. This study aims to obtain a butt joint obtained from TIG welding of AISI 304 stainless steel plate with a current of 40 - 60 A, identication of defects in the 1G butt joint, and analysis of the quality of the weld joint. The research method used is testing of welded joints using X-ray radiography which refers to the ASME V article II standard and the connection quality refers to ASME section IX. The results showed that TIG welding with a current of 60 Ampere produced a butt joint butt joint that was penetrated and there was no gap between the plates, whereas with a current of 40 A and 50 A the weld joint was not see-through but there was still a gap between the plates. Incomplete penetration weld defects were found in the welded SS 304 plate joints with a current of 40 A. Welded porosity defects were found in the welded SS 304 plate joints with a current of 50 A. Weld defects were not found in the SS 304 plate joints with a current of 60 A. Butt joint connections TIG welded SS 304 plate with the best current of 60 A compared to the current of 40 A and 50 A.

Analisis Radiografi Sinar-X Terhadap Sambungan Pelat Baja Tahan Karat Aisi 304 Hasil Pengelasan Tungsten Inert Gas Dengan Arus 40–60 Ampere

X-Ray Radiographic Analysis of Aisi 304 Stainless Steel Plate Joints From Inert Gas Tungsten Welding Results with 40 – 60 Ampere Current. Metal welding process is one of the main processes in machine construction. The quality of welded joints determines the strength and toughness of a machine construction. The quality of welded joints of installed construction can be determined by the non-destructive test method using X-ray radiography equipment. This study aims to obtain a butt joint obtained from TIG welding of AISI 304 stainless steel plate with a current of 40 - 60 A, identification of defects in the 1G butt joint, and analysis of the quality of the weld joint. The research method used is testing of welded joints using X-ray radiography which refers to the ASME V article II standard and the connection quality refers to ASME section IX. The results showed that TIG welding with a current of 60 Ampere produced a butt joint butt joint that was penetrated and there was no gap between the plates, whereas with a current of 40 A and 50 A the weld joint was not see-through but there was still a gap between the plates. Incomplete penetration weld defects were found in the welded SS 304 plate joints with a current of 40 A. Welded porosity defects were found in the welded SS 304 plate joints with a current of 50 A. Weld defects were not found in the SS 304 plate joints with a current of 60 A. Butt joint connections TIG welded SS 304 plate with the best current of 60 A compared to the current of 40 A and 50 A.

A novel approach to modelling the bond characteristics between CFRP fabrics and steel plate joints under quasi-static tensile loads

Carbon fiber-reinforced polymer (CFRP) materials have been effectively used as externally bonded sheets to repair damaged steel structures such as airplanes and ships. In this study, a series of double strap joints with different bonding lengths are considered and examined to experimentally and theoretically assess the effective bond length. Various models exist in the literature which are used to predict the strength of steel and CFRP joints under various loading conditions. Non-linear Lagrange stress method (NLS) which is a novel stress-based method for predicting the failure load values is presented for the first time. This approach is based on 2D and 3D linear elastic finite element analysis. Relying only on two experimental tests, the new approach proposed here can quickly and easily predict the failure load in steel/CFRP samples. In this methodology, it is assumed that the adhesive joint will fail as the normal stress along the adhesive mid-line reaches a predetermined value at a critical distance. In addition, experimental data on steel/CFRP joints gathered from the literature are compared to predictions using the NLS method. It was found that results from the theoretical predictions (NLS) were in good agreement with experimental tests conducted on double strap joints. It was also revealed that the average accuracy of the NLS method is superior to other methods such as cohesive zone model and Hart-Smith. The results revealed that under the best conditions, the NLS model is 5 times more accurate than existing models.

Experimental and Numerical Study of Mechanical Behavior of Welded Steel Plate Joints

This paper describes a study of welded steel plate joints using experimental and numerical methods. The objectives of this study are to observe the mechanical behavior of welded plate joints under monotonic and cyclic loads, identify their damage degradation processes, and provide useful test data for future damage analysis of beam-column connections in steel frame structures. Six specimens were designed, of which three were tested under monotonic loads, and the other three were tested under cyclic loads. The test setup consisted of three plates arranged in a cruciform and connected by two groove welds. The monotonic and cyclic loads were applied to the free end of the two outstanding plates, inducing a pulling force on the welded joint. Because the only element studied in the present work is the weld, the sizes of the three plates were kept constant. The responses of these welded plate joints are discussed in terms of their experimentally and numerically obtained mechanical parameters, hysteretic behavior, strain variations, stiffness degradation, damage process, and failure modes. The results show that the energy damage model outperforms the displacement damage model in terms of indicating the degree of damage. Furthermore, if designed according to code, all these welded plate joints perform satisfactorily.

Experimental and numerical investigations on the hybrid dowel and bonding steel plate joints for timber structures

This paper summarizes the experimental and numerical investigations on an innovative hybrid joint for timber structures. A total of 12 hybrid dowel and bonding steel plate joints divided in four subgroups were investigated. Different parameters such as the presence of self-tapping screws and the surface treatment of the bonding steel plate, were studied. For two subgroups, a vulcanized rubber layer was applied to the bonding steel plate, before gluing it onto the timber surface. Monotonic tensile tests were carried out on the proposed joints and three replicates for each subgroup were constructed. The focus of this research has been on the load-carrying capacity, shear stress and slip stiffness of the proposed joints. Test results showed that the load-carrying capacity of the hybrid joints was much higher than that of similar screw joints. The introduction of the vulcanized rubber layer in the specimens leaded to the slight improvement of load-carrying capacity and the remarkable improvement of maximum slip. The comparisons between numerical and experimental results indicated that the proposed numerical model had a satisfactory agreement with experimental results and could be used to simulate this hybrid joints. The numerical analysis showed that the shear stress was concentrated in edge regions of the bond line for specimens without rubber layer. While the shear stress distribution became much more uniform for specimens with rubber layer. The research results showed that the bonding steel plate joints with 3.0 mm rubber layer were characterized by both high deformability and high load-carrying capacity.

Variasi Spasi Baut terhadap Kuat Geser Sambungan Baut pada Pelat Baja

Errors in planning the spaces/distances between the bolts can weaken or create defects in the connection. Therefore, a research on the effect of bolt space on shear strength of bolt joints on steel plates is needed to find out the influence of the distance between bolts to the strength of double bolt joints on steel plate joints, whereas the long-term goal of this study is to determine the effect of the distance between bolts to the strength of the bolt connection in a plate connection system having more than two bolts. In the planning, the connection used bolt connecting devices that meet SNI 1729:2015 requirements. A tensile testing machine was used and the direct test method was conducted for shear strength of bolts in the plate joint system using two bolts. The bolt sample was installed in the plate connection system then the connection system was given a tensile load until it broke in the bolt sample. The peak load of the experimental results indicated the shear strength of the double bolt connection on the plate fluctuates. Average peak load for the sample of group I (20 mm bolt space), group II (40 mm bolt space), group III (60 mm bolt space), group IV (80 mm bolt space) and group V (100 mm bolt space) are 21.962 kN, 23.512 kN, 22.925 kN, 23.725 kN and 22.975 kN, respectively. The experimental results from each sample group showed the average peak load strength was greater than the theoretical shear strength value of 17.4974 kN.

Monitoring and Imaging of Bolted Steel Plate Joints Using Ultrasonic Guided Waves

Abstract Steel structures with bolted joints are easily dismantled and repurposed. However, maintaining joint integrity is a challenge. This paper reports a non-destructive methodology to monitor steel bolted joints. Piezoelectric ceramic patches have been surface bonded in the joint for transmission and reception of guided ultrasonic waves. Both single and multiple bolted joints have been investigated. It has been demonstrated that the variation in acoustic impedance due at the bolt interface can be discerned and calibrated with bolt torque level. The recorded reflections from interfaces are used as inputs for a newly developed imaging algorithm. The proposed method has the potential to be a reference-free and fully automated method.

Electrochemical Investigation of Oxygen Reduction Reaction on Type 316L Stainless Steel in NaCl Solutions in a Confined Space

Steel plate joints are commonly produced in the manufacturing process of steel structures such as automobiles and bridges. The steel plate joints suffer from aqueous corrosion in atmospheric environments. Especially, severe corrosion is often observed in the confined spaces between the steel plates because aqueous electrolytic solutions can be kept in the spaces. In this case, corrosion reaction rate of the steels in the confined space is basically controlled by the reduction reaction rate of dissolved oxygen. Therefore, it is important to estimate oxygen reduction reaction rate in the confined spaces to predict corrosion deterioration of steel plate joints. In this study, electrochemical investigation of oxygen reduction reaction rate in a confined space was performed. The material used in this study was austenitic stainless steel type 316L bar with various diameters from 5 to 20 mm. The type 316L bar was cut into a small cylindrical piece and the piece was embedded in epoxy resin after being contacted with a lead wire. The surface of the embedded stainless steel sample was ground with SiC papers down to JIS200 grit and then cleaned ultrasonically in EtOH. Test solutions were aqueous NaCl of different concentrations from 0.05wt% to 5wt%. The solutions were prepared with Milli-Q water and reagent grade sodium chloride. For the electrochemical measurements, the sample was set horizontally in a plastic vessel and then an acrylic rod of 20 mm in diameter, which was used as a crevice former, was placed above the sample surface to make a confined space between the sample and the rod. The gap between the sample surface and the rod was changed from 20 um to 200 um by using a laser displacement meter. Electrochemical measurements were conducted by a conventional three electrode method with a platinum wire (Pt) and a Ag/AgCl in a saturated KCl (SSE) as a counter electrode (CE) and a reference electrode (RE), respectively. Cathodic polarization curves for the sample were measured with various gaps at a potential sweep rate of 0.5mV/s. Cathodic polarization behavior for the sample measured in the confined spaces was similar as that measured in a bulk solution; a limiting current region due to oxygen reduction reaction was observed on the samples of various diameters in a confined space. It was confirmed that the limiting current density decreased with decreasing in the gap. This is attributed to be the difference in the oxygen diffusion rate on the sample in the confined space.

Numerical study of the effect of carbon fiber/epoxy resin adhesive thickness on the creep behaviour of carbon steel plate joints

Nowadays, the use of adhesive and adhesively bonded joints have been considerably appreciated in the industry due to the dramatic reduction in bonding strength, reduced stress concentration, rust prevention, uniform bonding of the bonding surface and a significant reduction in costs compared to other types of permanent joints such as welding. In this study, the effect of adhesive thickness on creep behaviour of a single lap adhesive joint with the aid of Abaqus FEM software is investigated. It should be noted that the two-layer and two-dimensional models are considered, in which their adhesive layer is made of a reinforced epoxy resin with 0.5% carbon fiber and the adherend layers are made of carbon steel plates, which is affected by tensile forces. Since the main purpose of this paper is to study the effect of adhesive thickness on the adhesive joints behaviour, the effects of the distribution of shear stress, effective stress and creep strain were studied in different thicknesses of the adhesive layer. The results show that by increasing the thickness, the stress and the creep strain decrease, and over time, the stress decreases and the creep behaviour of adhesives increases.

Welding Residual Stress Effect in Fracture Toughness.

The thickness of steel plates used for large structures has been increasing with the rapid increase in the size of welding structures. The growing capacity of large-scale ships, such as container ships, has led to an increase in the thickness and strength of steel plates for shipbuilding. The steel plate toughness and resistance to brittle fractures tend to decrease for thick plates because of the so-called thickness effect. This study uses 80-mm-thick steel plates and two welding processes (i.e., flux cored arc welding process and electron gas welding process) to produce full-thickness weld joints. The welding residual stress in both welded joints is measured to evaluate the brittle crack propagation path. This study aims to investigate the effect of welding variables on the crack arrest toughness and crack propagation path of thick steel-plate welds. The thick steel plate has a high possibility in brittle fracture. A quantitative analysis is conducted through a temperature-gradient ESSO test to clarify the effect of the welding variables on the flux cored arc welding and electron gas welding process joints of steel plates with 50 and 80 mm thicknesses. The welding residual stress is also measured to evaluate the welding residual stress effect in both welding processes on the brittle crack propagation path using a neutron science analysis.

Numerical Prediction of Penetration Shape in Metal Active Gas Welded Joints of Steel Plates

It is important to predict the penetration shape of welded joints because the penetration shape strongly affects the strength of joints. As one of the methods for simulating gas metal arc welding (GMAW) process, a three-dimensional, non-stationary thermal model has been developed. By using a finite differential model based on the heat flow equation and taking account of the balance of gravity, surface tension and arc pressure, both molten pool and the penetration shape are successively demonstrated. Although the finger type penetration which is generally observed in metal insert gas (MIG) welding of aluminum alloy can reproduced by developing an additional line heat source, the finger type penetration obtained in metal active gas (MAG) welding of the steel plates cannot be predicted. In this research, a new point heat source was developed instead of the line type heat source and the applicability of this new model was examined. From the serial computations for the penetration shape of bead-on welding, the dominant parameters in the new model which are thermal efficiency, ratio of heat source and radius of arc pressure were determined. Then, by using these values obtained, the penetration shapes of lap and fillet joints of steel plates can be successively reproduced, where the influence of arc radius change on the ratio of heat source was taken into account.

Lamb wave-based monitoring of shear failure of an adhesive lap joint

The paper presents a study on the elastic wave propagation in adhesive joints of steel plates subjected to tensile loading. A single lap joint was chosen for analysis because of its simplicity and plurality of applications. Experimental investigations consisted of the uniaxial extension of prepared specimens. Force and displacement values were recorded by a testing machine. Simultaneously, guided Lamb waves were excited and signals of their propagation were collected in a number of points by piezoelectric transducers attached to the specimen surface. Further processing of signals allowed to determine some disturbances in gathered data. The continuous wavelet transform revealed discontinuities in force-displacement relations. The Fourier transform showed changes in frequency values of recorded signals. Large disturbances of the root mean square values was also observed. The results of all analyses allowed to conclude that the identification of partial degradation state before the sample destruction was possible.

An environmental impact on the condition of an unfinished building in the OWT technology

The aim of the paper is to present the state of the building erected in the OWT technology. The construction of the building has not been completed due to the financial problems of the late 90's of the XX century. As a result of the long-term environmental impact, the object was degraded due to the lack of a flat roof and windows. The impact of precipitation, wind and biological corrosion led to significant degradation and deterioration of structural elements and joints. The paper will present examples of damage caused by environmental impacts. Examples of damage of wall and floor elements as well the deeply corroded steel plate joints will be presented. Highly grown lichens, mosses or mold will be also presented as the examples of biological interactions onto the surface of constructional elements. Structural elements have been tested in a nondestructive manner using sclerometer tests. The results will be described and the conclusions will be presented. The analyzed object presents in an interesting manner that environmental influences could destructively affect the construction of precast RC structural elements, which constitute a significant percentage of the Polish construction market.

Analysis of influence of initial gap of laser-arc hybrid butt welds on inherent strain and welding deformation of a pipe structure

Although the laser-arc hybrid welding process has the advantages of smaller deformation and wide freedoms using different energy ratios, some initial dimension errors such as initial gap or initial mismatch before welding assembly have a significant influence on the final shape of welded structures. In this paper, a thermal elastic-plastic finite element model was developed to investigate the temperature fields and plastic strains in butt joints of steel plates with three different initial gaps (0.2 mm, 0.5 mm, and 1.0 mm). Four inherent deformation parameters, longitudinal inherent shrinkage, transverse inherent shrinkage, longitudinal inherent bending, and transverse inherent bending, were calculated and compared with different initial gaps. Finally, welding deformation in a steel pipe structure with five weld lines was predicted by the inherent strain theory.

Impact Fracture of Jointed Steel Plates of Bolted Joint of Cars

The present study is concerned with the development of a fracture criterion for the impact fracture of jointed steel plates of a lap bolted joint used in the suspension parts of a car body. For the accurate prediction of crash characteristics of car bodies by computer-aided engineering (CAE), it is also necessary to examine the behaviour and fracture of the jointed steel plates subjected to impact loads. Although the actual impact fracture of jointed steel plates of a lap bolted joint in cars is complicated, for simplifying it is classified into the shear fracture and the extractive fracture of jointed steel plates. Three kinds of steel plates, i.e., common steel with the tensile strength of 270 MPa and two high tensile strength steels with the tensile strength of 440 and 590 MPa level used for vehicles, are examined. In the impact shear test, the specimens are made of two plates and jointed by a bolt, and in the impact extractive test the specimens are made of a plate and drilled in the centre for a bolt. The impact shear test of jointed steel plates of lap bolted joints is performed using a modified split Hopkinson bar apparatus, while the impact extractive one is performed using one-bar method. Numerical simulations by a FEM code LS-DYNA are also carried out in order to understand the mechanism of shearing and extractive fractures process of jointed steel plates. The obtained results suggest that a stress-based fracture criterion may be developed for the impact shearing and extractive fractures of jointed steel plates of lap bolted joints used in a car body.

Evaluation of Bonding between High Modulus CFRP Sheet and Steel after Environmental Exposure and Fatigue Loading

This study investigated the effects of fatigue loading and corrosive environment on bonding strength and failure modes of Carbon Fibre Reinforced Polymer (CFRP)-laminated steel. A series of tests on CFRP bonded steel plate joints was conducted. The joints were immersed in the temperature controlled sea-water with a preload. After immersions for one and six months, they were subjected to cyclic loading for a pre-set number of cycles, and then tensioned to failure. The effect of fatigue loading alone was studied by the authors in the past. In the present study, the results of the cyclic and static loading tests were compared. The comparisons between the current and previous results have provided data on the durability of CFRP/steel joints under this environmental condition.

Shear fracture of jointed steel plates of bolted joints under impact load

The present study is concerned with the development of a fracture criterion for the impact fracture of jointed steel plates of bolted joints used in a car body, which contributes to crash simulations by CAE. We focus our attention on the shear fracture of the jointed steel plates of lap-bolted joints in the suspension of a car under impact load. Members of lap-bolted joints are modelled as a pair of steel plates connected by a bolt. One of the plates is a specimen subjected to plastic deformation and fracture and the other is a jig subjected to elastic deformation only. Three kinds of steel plate specimens are examined, i.e., a common steel plate with a tensile strength of 270 MPa and high tensile strength steel plates of 440 and 590 MPa used for cars. The impact shear test was performed using the split Hopkinson bar technique for tension impact, together with the static test using a universal testing machine INSTRON 5586. The behaviour of the shear stress and deformation up to rupture taking place in the joint was discussed. The obtained results suggest that a stress-based fracture criterion may be developed for the impact fracture of jointed steel plates of a lap-bolted joint.