Effect Of Overlap Length Research Articles

Mechanical Properties of Cold‐Welded CoCrFeCuNi Nanowires with Side‐by‐Side Contact: A Molecular Dynamics Study

Cold welding at the nanoscale is a promising technique for bottom‐up fabrication and assembly of nanostructured materials. Herein, the cold welding process of the CoCrFeCuNi high‐entropy‐alloy (HEA) nanowires in the form of side‐by‐side contact using molecular dynamics simulation is inestigated. The effects of overlap length, crystal orientation, and temperature are taken into consideration. The results demonstrate that strength is positively correlated with the overlap length. Fracture strain first increases up to a maximum and then decreases with the increase in overlap length. When the temperature increases from 300 to 900 K, the ultimate stress of the welded nanowires decreases from 1.18 to 0.87 GPa, and the welding stress decreases from −0.54 to −0.26 GPa. The crystal orientation significantly influences the deformation mechanism. For samples welded by nanowires with the same crystal orientation, the primary deformation mechanisms are twinning and dislocation slip. However, for samples welded by nanowires with different crystal orientations, the deformation is primarily mediated by the grain boundary slip. The research can enhance the understanding of the cold welding behavior for low‐dimensional materials and is hopeful to provide some valuable guidance for the bottom‐up fabrication and assembly of HEA nanocomponents.

Effect of overlap length on the strength of adhesive joints of steel sheets

The study evaluates the shear strength of the single-lap adhesive joints made of C45 carbon steel. The influence of the overlap length on the shear strength of the adhesive joint was tested. The elongation of the samples was also tested. Before the bonding process, the samples were treated with P180 abrasive paper and degreased. The adhesive joints were made using the Epidian 53/Z1/100:10 adhesive composition. The strength tests were carried out on a Zwick/Roell Z150 testing machine. The maximum value of the shear strength was obtained for the lap Lz1 = 13 mm and the minimum for Lz4 = 19 mm.

Numerical analysis of elasto-plastic adhesively single step lap joints with cohesive zone models and its experimental verification

Adhesive bonding method is used as an alternative to mechanical bonding methods, and it is frequently used in automotive, space and aviation industries. In the present study; the displacement and failure load capacity characteristics of single step lap joint was measured experimentally and compared with results of finite element (FE) analysis. In addition, the change in the length and the thickness of the material and adhesive in this joint type, stresses on the adhesive was examined by numerical analysis that have affected. Also, the effects of overlap length and material thickness on the stresses in adhesive were examined with numerical analysis for the single step lap joint. AA2024-T3 aluminum alloy adhered material and double component DP460 structural adhesive was used as adhesives in the single step lap joint. In the numerical analysis of this joint type, two different material models including multilinear isotropic hardening (MISO) and cohesive zone model (CZM) were used in the adhesive layer. During the experimental tests, two cameras were used to measure the displacements and crack propagations. As a result, the data obtained from the numerical analysis were compared to the experimental data of the single step lap joint type, the use of CZM in the adhesive region was found to be very important in terms of compliance. Thus, the difference between CZM and MISO results in terms of damage load in adhesive is 7 %, while this difference is 32 % in terms of displacement. Also, it has a great importance to get the displacement data via a video extensometer for the compatibility of FE and experimental analyses. Another result obtained from the study is that changing the material thickness, the adhesive thickness and the overlap length in the joint, changes the stress concentrations and shear stresses at the ends of the overlap area.

Effects of Overlap Length on Flammability and Fire Hazard of Vertical Polymethyl Methacrylate (PMMA) Plate Array.

Polymethyl methacrylate (PMMA) plates are widely used in buildings or factories for natural lighting. Commonly PMMA plates are installed as a discrete array. However, PMMA plates are very susceptible to fire. Therefore, experimental study on flammability and fire hazard of vertical PMMA plate array with different overlap length (D) was conducted in this work. The average flame height () increases first and then decreases with an increase in the overlap length, and reaches the maximum when D = 40 mm. The discrete flame spread speed () also rises first and then drops with the increase of D, which is mainly due to the heat transfer from the PMMA flame to the next plate. A model for predicting the flame spread rate of discrete PMMA array is established. The predicted results are consistent with experimental ones, with a predicted error smaller than 15%. The average temperature of flame zone rises first and then drops as D increases, reaching the maximum when D = 40 mm. This leads to the same changing trend of radiative heat flux. Results obtained in this work provide a reference for fire hazard evaluation and fire safety design of PMMA plates employed in buildings or industrial sites.

The effect of joint configuration on the strength and stress distributions of dissimilar adhesively bonded joints

The recent increase in the use of adhesively bonded joints (ABJs) made from dissimilar adherends demands the acquisition of a better understanding of the strength and behaviour of these joints, including their failure mechanisms. Several studies have reported on such joints individually, however few have compared the performances of dissimilar ABJs with varying configurations and design parameters, in order to determine the optimal design configuration for hybrid structures. In this work, a comparative study using experimental methods and finite element analysis was conducted, focusing on four joint configurations (scarf joints, stepped-lap joints, half-lap splice joints and single-lap joints), with the aim of evaluating the ways in which their performances differ. In addition, the effects of overlap length (L0) and the mechanical properties of the adherends on the overall success of each joint were particularly closely analysed and compared. The results showed that the scarf joint provided the best performance of all the designs discussed, and it was found that increasing the overlap length was only significantly beneficial for certain joint configurations and adherend combinations. When the overlap length was increased from 12.5 mm to 25 mm, the failure load increased by 47.50% and 21.25% for the scarf and the stepped-lap joints, respectively. In comparison, the percentage increases for the half-lap splice and single-lap joints under the same conditions were less than 10%. Moreover, the mechanical properties of the adherends considerably affected the failure mechanisms of the dissimilar joints, and for all four joint configurations, the failure was initiated by a crack at the adherend-adhesive interface adjacent to the adherend with a lower modulus.

겹침 길이가 튜브 배열의 풀비등에 미치는 영향

겹침 길이와 하부 튜브 열유속의 복합적인 효과가 튜브 다발의 풀비등 열전달에 미치는 영향을 규명하기 위하여 실험적인 연구를 수행하였다. 실험을 위해 대기압 상태의 물 속에 잠긴 두 개의 스테인리스강 튜브를 사용하였다. 겹침 부분은 가열 튜브의 1/2에서 1.0까지 1/4 간격으로 변화시켰다. 전체 겹침 길이에 걸쳐, 피치가 작고 상부 튜브의 열유속이 낮을 때 열전달 향상이 분명하게 나타났다. 겹침 길이가 크고, 하부 튜브의 열유속이 높을 때 열전달이 향상되었다. 하부 튜브로부터 상부로 이동하는 기포에 의해 발생하는 액체 교란과 대류 유동이 열전달 향상의 주된 이유로 판단된다.

Progressive Damage Modelling of Transverse Impact Behavior of Adhesively Bonded Composite Joints

A three-dimensional dynamic numerical model was developed, using the commercially available finite element software LS-DYNA to simulate the Low Velocity Impact (LVI) case on bonded joints consisting of woven CFRP adherents. The adhesive failure simulated using the Cohesive Zone Method (CZM), while the failures in the composite material simulated using a progressive damage material model based on Hashin’s failure criteria. The numerical results were compared with the corresponding numerical and experimental data found in literature, showing good agreement regarding the damage area and the global structural response. However, the maximum contact force was underestimated by 18.2% due to premature fiber failure in the lower adherent as a result of tensile bending stresses. In the adhesive layer, the stress distribution was found to alter from tensile near the edge of the lower substrate to compressive close to the edge of the upper substrate. The cohesive failure initiated from the edge under mixed mode loading while it propagated along the overlap length under mode II dominated loading. Following, a study on the effect of the post damage parameters of the CFRP material model to the damage accumulation of the joint was conducted. These parameters were calibrated according to experimental data from literature. The modified model was used for the estimation of residual tensile strength of the bonded joint containing impact induced damage. The results show tensile strength decrease of 16.3% for the joint with 25.4 mm overlap length and impact energy of 10 J. Finally, the effect of overlap length and impact energy was studied, in the means of damage accumulation in the CFRP and adhesive material and residual tensile strength of the joint. It was found that increasing the overlap length lead to reduction of the disbonding area due to impact loading resulting in lesser decrease of the residual tensile strength of the joint. For low impact energy of 5 J the associated damage in the adherents and the adhesive is minimal and doesn’t affect the tensile strength of the joint. Increasing the impact energy resulted in significant increase in the damage accumulation of the joint leading to equivalent decrease in the tensile strength.

Optimization of Joint Strength of Adhesively Bonded Glass Fiber Epoxy Based Double Strap Butt Joint

Fiber reinforced composite laminates has various industrial applications. It is important to investigate the joining methods of composite laminates. In this research paper, the effect of overlap length (OL), surface roughness (SR) and adhesive layer thickness (ALT) on the strength and failure modes of adhesively bonded double strap GFRP (glass fiber reinforced epoxy based composite laminate) butt joint was investigated. The adhesively bonded double strap GFRP butt joints were prepared from unidirectional glass fiber and epoxy by hand layup technique as per ASTM standard. The number of experiments was optimised using Taguchi’s L9 approach. It is observed that the variation in overlap length has significant effect on butt joint strength. It is also observed that SR and ALT are less significant factors in comparison to OL. It is concluded that increase in ALT adversely affect the butt joint strength. The failure mode in specimens was generally thin layer cohesive failure or light fiber tear failure.

Effects of overlap length on the strength of bolted, bonded and hybrid single lap joints with different adherend materials and thicknesses

This study evaluates the effects of the overlap length and different adherend materials with different thicknesses on the mechanical performance of the bolted (BJ), adhesively bonded (ADJ) and hybrid joints (HJ) subjected to quasi-static axial tensile loading. The three different joints were fabricated and tested according to 36 different variances, including two kinds of adherend materials (AL6061 and Al7075 with different yield strength, tensile strength and ductility values), three adherend thicknesses (2 mm, 4 mm and 6 mm) and two overlap lengths (25 mm and 45 mm). Numerical models were implemented and developed using the commercial software Abaqus/Explicit. The adhesive layer (AF163-2K) was simulated by using cohesive interface elements with traction-separation response. Ductile/shear damage models were used to simulate the failure behavior of the adherends and the bolt material. To interpret the strength of various joints, failure behavior for each configuration is analyzed widely.

Dual-material gate dual-stacked gate dielectrics gate-source overlap tri-gate germanium FinFET: analysis and application

This study proposes a novel dual-material-gate dual-stacked-gate dielectrics gate–source overlap Ge FinFET and compares its characteristics with conventional FinFET. The proposed device shows very less leakage current (IOFF) (~ 10−17 A), significant on drain current (~ ION) (~ 10−4 A), very high ratio of ION to IOFF (ION/IOFF) (~ 1013) and less subthreshold swing of (SS) (71 mV/dec). This study presents the effect of different dielectrics, oxide thicknesses (tox) and back-gate voltages (VGB) on transfer characteristics of the proposed device. The effect of channel concentration on ION/IOFF, threshold voltage (Vth), transconductance (gm) and SS is also investigated. The effect of overlap length (Lov) on analog parameter, gate–source capacitance (Cgs), is also analyzed. Moreover, the effect of fin thickness (Tfin) on Vth and SS is also studied. The height of the BOX plays an important role in reducing IOFF. Moreover, with emphasis on digital application, by using the proposed device a digital inverter circuit is implemented, and this study investigates the characteristics using mixed-mode simulation.

Impact Joining of Similar and Dissimilar Metal Plates at their Edges

Impact joining device was developed to achieve the joining at plate edge. The sheared faces obtained by high-speed shear are availed in the joining method. The temperature remarkably elevates and the material softens in the thin severely deformed layer. The cut faces are contacted each other with sliding motion immediately after shearing process. Slight overlap for the opposed cut faces is set. In the similar material combination of mild steel (SPC), the effect of overlap length on the average joining efficiency was not clear. The data spread became smaller for the shorter overlap length. Microscopic observation discovered that there is a narrow band where the grain flow was not visible due to the remarkable temperature rise. In the dissimilar material combination of titanium (TP340C) and SPC, generation of a certain metallic compound was implied by energy dispersive X-ray analysis.

Effect of overlap length and scarf angle on the mechanical properties of different adhesive joints subjected to tensile loads

Abstract In this study, the effect of adherend dimensions and scarf angle on mechanical behavior of different adhesively bonded joints was analyzed. The adhesive joints were subjected to tensile load. The stresses were analyzed by three-dimensional finite element method. The three-dimensional finite element method calculations were performed by using ANSYS (verification 14.0.1). The strength of three different lap joint types with similar bonding area (W = 25 mm, L = 10 mm) and adherend thickness were examined. Numerical results were found to be quite reasonable. Also, they indicate that the maximum stresses in the different joints can be significantly reduced by changing the dimensions of different joints. The double lap joints were the highest ultimate failure loads.

Effects of Different Curvature Patches on the Strength of Double-Strap Adhesive Joints

In general, the damage in adhesively bonded joints initiates from and propagates through the ends of the overlap area due to high stress concentration in that area. The reduction of these stress concentrations results in an increase in the strength of the joints. For this reason, the rounding of the overlap region before bonding and then applying compression during the bonding process will exert compressive residual stresses on the adhesive layer in the overlap end regions. It is known that the residual stresses formed in this process increase the failure strength of the joint and hence delay the initiation of the damage. In this study, the effects of overlap length (L = 50,75, and 100 mm), patch thickness (h = 1.6, 3.2, and 5 mm) and patch materials (AA2024 aluminum alloy, AISI 304 steel, AISI 1040 steel) on bond strength were experimentally investigated for adhesively bonded double-strap joint (DSJ) and curvature double-strap joint (CDSJ) subjected totensile loading. The experimental study showed that the overlap length, patch thickness and patch materials have considerable influence on the failure strength and displacement capacity of the joints.

Statistical analysis of the influence of input process parameters on characteristics of weld bonds of Al 5052 H32 alloy using a Box–Behnken design

This article presents a systematic study on the effect of input process parameters of the weld-bonding process, namely curing temperature, curing time, welding pressure, welding time and welding current, on the characteristics of the weld bonds, such as bond-line thickness, equivalent nugget diameter, corona size and ultimate shear tensile strength using a Box–Behnken design approach. The effect of overlap length and surface roughness on the shear tensile strength of weld bonds was studied by conducting pilot experiments using a single variable approach. Thereafter, effects of input process parameters, such as curing temperature, curing time, welding pressure, welding time and welding current, on various characteristics of weld bonds was studied by conducting the main experiments according to the Box–Behnken design and response surface methodology (RSM). Regression models were developed to study the influence of input process parameters of weld bonding on characteristics of weld bonds, i.e. bond-line thickness, equivalent nugget diameter, corona size and ultimate shear tensile strength. A combination of weld bonding process parameters for maximum shear tensile strength of the weld bond was obtained with the help of analysis. Further, efforts were made to correlate the bond-line thickness, equivalent nugget diameter and corona size with ultimate shear tensile strength of weld bonds. Developed regression models were validated by conducting confirmation experiments.

An Experimental Study on the Effect of Overlap Length on the Failure of Composite-to-Aluminum Single-Lap Bonded Joints

Carbon composite-to-aluminum single-lap adhesive joints with six different bonding lengths were tested under tension. The main objective of this study is to investigate the relationship among the failure loads, modes, and bonding lengths of the joints. It is shown that the final failure modes of the joints are caused by delamination in the composite adherend, and that the delamination patterns vary depending on the bonding length. It was also observed that the failure loads are affected by the delamination patterns. The study's conclusion is that to achieve the maximum strength of the adhesive, the joints should be designed to have strong resistance to delamination.

Fatigue behaviour and damage evolution of single lap bonded joints in composite material

The paper presents the results of an experimental investigation on the fatigue behaviour of single lap bonded joints. Carbon/epoxy laminates bonded with epoxy adhesive were tested under tension–tension fatigue loading and the effect of overlap length and corner geometry was discussed by using the classical stress-life approach. Significant improvements in fatigue strength can be obtained by adopting long overlap length and spew fillet corner geometry. A careful analysis of the evolution of the fatigue damage was also carried out and it was observed that a significant fraction of the fatigue life of the joint is spent in the nucleation of one or more cracks which then propagate up to failure of the joint. The duration of nucleation process, which can last from 20% up to 70% of the joint life, suggests the need of incorporating this phase in the development of future predictive models. The fatigue crack propagation process is also discussed and the rates of crack propagation evaluated.

Effect of overlap length on durability of joints bonded with a pressure-sensitive adhesive

In this study, the effect of overlap length on durability of a film type adhesive, Structural Bonding Tape (SBT) 9244, which possesses pressure-sensitive and visco-elastic properties, was investigated. Single-lap joints with 1.62 and 3.2 mm adherend thicknesses and at 12.5, 25 and 50 mm overlap lengths consisting of AA2024-T3 alloy as the adherend were exposed to two environmental conditions for exposure times of up to 90 days. The exposure environments were 100% relative humidity (RH) and 3.5% NaCl solution. At the end of exposure times, the failure surfaces were examined by Scanning Electron Microscopy (SEM) after the strength of joints was determined with the lap shear test. It was observed that with increasing overlap length, not only the failure load increased, but also the degradation rate decreased. In addition, as the metal adherends do not absorb any water and moisture from the environments, the metal adherend thickness had no effect on durability of the adhesively bonded joints.

Effect of Overlap Length and Adhesive Thickness on Stress Distribution in Adhesive Bonded Single-Lap Joints

Effect of Overlap Length and Adhesive Thickness on Stress Distribution in Adhesive Bonded Single-Lap Joints

The effects of overlap length and adherend thickness on the strength of adhesively bonded joints subjected to bending moment

In this work, elasto-plastic stress analysis of a Single Lap Joint (SLJ) subjected to bending moment was investigated using 2D non-linear Finite Element Analysis (FEA). The SLJs, consisting of hardened steel as the adherend bonded by two adhesives, one stiff and one flexible, with very different mechanical behaviors were analyzed. In order to determine the effect of geometrical parameters on the performance of the SLJs, four different adherend thicknesses and overlap lengths for each adhesive were used. For verification of the analysis, the FEA results were compared with experimental results. It was observed that there was a significant effect of adherend thickness on the strength of the joint with both adhesives. However, the load carried by the SLJ with the flexible adhesive increased with increasing overlap length.

617 単純重ね合わせ接着継手のき裂進展経路に及ぼすラップ長さの影響(OS 接着・界面)

617 単純重ね合わせ接着継手のき裂進展経路に及ぼすラップ長さの影響(OS 接着・界面)