scholarly journals Influence of Assembly Gap Size on the Structure and Properties of SUS301L Stainless Steel Laser Welded Lap Joint

Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 996
Author(s):  
Hongxiao Wang ◽  
Yanxin Wang ◽  
Xin Li ◽  
Wenquan Wang ◽  
Xiwei Yang

The microstructure and properties of laser welding lap joints with different assembly gap sizes are experimentally investigated. The laser weld joint is composed of γ-austenite and δ-ferrite, and the strip ferrite phase is mainly distributed at the austenite grain boundary. The weld metal presents the austenitic-ferritic (AF) solidification mode. When there is a gap between the two plates, a triangular region composed of similar equiaxed crystals can be found, and the size of the cellular crystals in this region decreases significantly. When the assembly gap size increases from 0.1 mm to 0.4 mm, the weld penetration state of the joint changes from full penetration to semi-penetration, and the surface collapse increases. The excessive size of the gap leads to a decrease in the tensile-shear force and fatigue strength of laser welded joints. In order to ensure that the surface morphology and properties of the welded joint meet the quality standard and requirement, the assembly gap should be less than 0.1mm.

Open Physics ◽  
2019 ◽  
Vol 17 (1) ◽  
pp. 320-328
Author(s):  
Delin Sun ◽  
Minggao Zhu

Abstract In this paper, the energy dissipation in a bolted lap joint is studied using a continuum microslip model. Five contact pressure distributions compliant with the power law are considered, and all of them have equal pretension forces. The effects of different pressure distributions on the interface stick-slip transitions and hysteretic characteristics are presented. The calculation formulation of the energy dissipation is introduced. The energy dissipation results are plotted on linear and log-log coordinates to investigate the effect of the pressure distribution on the energy distribution. It is shown that the energy dissipations of the lap joints are related to the minimum pressure in the overlapped area, the size of the contact area and the value of the power exponent. The work provides a theoretical basis for further effective use of the joint energy dissipation.


1953 ◽  
Vol 20 (3) ◽  
pp. 355-364
Author(s):  
R. W. Cornell

Abstract A variation and extension of Goland and Reissner’s (1) method of approach is presented for determining the stresses in cemented lap joints by assuming that the two lap-joint plates act like simple beams and the more elastic cement layer is an infinite number of shear and tension springs. Differential equations are set up which describe the transfer of the load in one beam through the springs to the other beam. From the solution of these differential equations a fairly complete analysis of the stresses in the lap joint is obtained. The spring-beam analogy method is applied to a particular type of lap joint, and an analysis of the stresses at the discontinuity, stress distributions, and the effects of variables on these stresses are presented. In order to check the analytical results, they are compared to photoelastic and brittle lacquer experimental results. The spring-beam analogy solution was found to give a fairly accurate presentation of the stresses in the lap joint investigated and should be useful in analyzing other cemented lap-joint structures.


1998 ◽  
Vol 120 (1) ◽  
pp. 106-113 ◽  
Author(s):  
T. Reinikainen ◽  
M. Poech ◽  
M. Krumm ◽  
J. Kivilahti

Solder alloys are commonly tested with shear tests to study their mechanical properties or low-cycle fatigue performance. In this work, the suitability of various shear tests for quantitative solder-joint testing is investigated by means of the finite element method. The stress state and stress distribution in the following well known geometries are studied: the double-lap test, the ring and plug test, the losipescu test, and two single-lap tests. A new test geometry, the grooved-lap test, is introduced and compared to the conventional tests. The results of simulations with an elastic material model in plane-strain indicate that considerable differences in the purity of the state of shear (rε = −ε1/ε3) as well as in the stress distribution in the joint exist among the shear tests. However, simulations with a nonlinear material model show that stress inhomogenities are smoothed by the plastic and creep deformation occurring in the joint. Optical measurements of the deformation of real single-lap and grooved-lap joints show that the single-lap joint rotates slightly during creep, whereas in the grooved-lap joint no rotation can be detected. This confirms the simulation results that in the single-lap test the initially nonuniform stress distribution changes during creep, and in the grooved-lap test the uniform stress distribution remains constant through the test.


2019 ◽  
Vol 142 (1) ◽  
Author(s):  
Wei Li ◽  
Wanglong Zhan ◽  
Ping Huang

Abstract A general contact model for a lap joint interface based on non-Gaussian surfaces was proposed. The effect of surface topography parameters on microslip behavior in a lap joint interface was studied. Pearson system was applied to produce non-Gaussian surfaces. Combining the topographical-dependent Zhao–Maietta–Chang (ZMC) model with the physical-related Iwan model, the nonlinear constitutive relationship of a lap interface was constructed by using Masing hypothesis. Meanwhile, the probability density function of asperity heights of an infinitely smooth surface was mathematically proved to be a delta function, verifying that the calculated value of friction in the model conforms to the physical law. Gauss-Legendre quadrature was conducted to calculate contact relations of different Pearson distribution surfaces. Furthermore, numerical results of microslip loops under oscillating tangential forces were compared with the published experiments, indicating the present model considering non-Gaussian surfaces could agree well with the experiments.


Author(s):  
Terry E. Shoup ◽  
Michael Drew

This paper presents two easy-to-use spreadsheet modules in Microsoft Excel to assist with the design of adhesive joints. The modules make use of embedded Visual Basic numerical algorithms to give assistance with the selection of both the adhesive type and the geometric configuration of an adhesive lap joint. These modules facilitate the quick implementation of designs that are more accurate than was previously possible by traditional design methods. The method will be particularly helpful to students and inexperienced designers who first encounter the need to design adhesive joints. The paper also includes an example application to illustrate the use of the modules.


2017 ◽  
Vol 52 (18) ◽  
pp. 2477-2482 ◽  
Author(s):  
Hei-Lam Ma ◽  
Xiaoqing Zhang ◽  
Kin-tak Lau ◽  
San-qiang Shi

Nanoclay has been a popular kind of nanofiller for polymer-based nanocomposites in industries since adding a small amount of it can effectively enhance the mechanical properties of polymer. In the present study, a suitable sonication time was first found for manufacturing nanoclay/epoxy adhesive. Then, the lap joint shear strengths of nanoclay/epoxy adhesives with different nanoclay content (0, 1, 3, 5 wt%) conditioned at both room temperature and cryogenic temperature environment were investigated. The main failure mechanism of all samples was interfacial failure between the first layer of glass fiber and adhesive due to peeling. Results showed that 1 wt% was the optimal nanoclay concentration for cryogenic temperature. Scanning electron microcopy was used to examine the fracture surfaces of samples. Good exfoliation and dispersion were found in samples containing 1 wt% of nanoclay. Adding nanoclay into epoxy did not greatly affect the lap joint shear strength at room temperature but significantly influence the strength at cryogenic temperature. This was due to a clamping force induced on nanoclay by negative thermal expansion during conditioning from room temperature to cryogenic temperature. With good exfoliation and dispersion, the clamping force can be evenly distributed. Hence, 1 wt% nanoclay/epoxy adhesive is suitable for bonding composite lap joints, which will be servicing at low temperature environment.


2013 ◽  
Vol 5 (3) ◽  
pp. 409-417 ◽  
Author(s):  
Jochen O. Schrattenecker ◽  
Andreas Haderer ◽  
Günther Reinthaler ◽  
Andreas Stelzer

In this paper, we present the results of using a frequency-stepped continuous-wave radar system to estimate the position of overlapping and electrically good conductive plates. We especially focus on polarimetric scattering effects caused by the step of a lap joint, which is a common welding-geometry. To model the step's contribution to the overall scattered signal, we use a two-dimensional combined field integral equation (CFIE) approach. For demonstrating its practical applicability, the implemented scattering model is verified by measurements. To emphasize the improvements of position estimation by using a CFIE approach, the outcomes of the model are compared to a commonly used point scattering model. Finally, the numerical signal is utilized to precisely estimate the position of the lap joint.


Author(s):  
SMJ Razavi ◽  
MR Ayatollahi ◽  
M Samari ◽  
LFM da Silva

This paper addresses numerical and experimental examination of the role of zigzag interface shapes on the load bearing capacity and fatigue life of adhesively bonded single lap joints. Aluminum adherends with non-flat zigzag interfaces were tested under both quasi-static and fatigue loading conditions. The quasi-static test results revealed that the non-flat adhesive joints have higher load bearing capacity compared to the conventional flat single lap joints. Comparative fatigue tests with different loading levels revealed that the non-flat zigzag single lap joint had considerably higher fatigue life than the conventional lap joint.


2014 ◽  
Vol 939 ◽  
pp. 39-46 ◽  
Author(s):  
Hong Qian Xue ◽  
Qian Tao ◽  
Emin Bayraktar

The aim of this study is to examine the effect of the clearance and interference-fit on the fatigue life of composite lap joints in double shear, 3D finite element simulations have been performed to obtain stress (or strain) distributions around the hole due to interference fit using FEM package, Non-linear contact analyses are performed to examine the effects of the clearance and interference for titanium and composite lap joint. Fatigue tests were conducted for the titanium and composite lap joints with clearance fit and interference fit with 0.5, 1, and 1.5% nominal interference fit levels at different cyclic loads. The results shows that interference fit increases fatigue life compared to clearance fit specimens, the titanium and composite lap joint with 1% interference fit level has the better fatigue life.


2021 ◽  
Vol 100 (12) ◽  
pp. 396-409
Author(s):  
ABDELBASET R. H. MIDAWI ◽  
◽  
ELLIOT BIRO ◽  
SRINATH KISTAMPALLY

Advanced high-strength steels (AHSS) such as complexphase (CP) and high-formability (HF) steel offer weightsaving advantages for automotive applications such as chassis and frame applications. To prevent material oxidation, materials are often galvanized to protect the substrate from corrosion. However, the weldability of coated AHSS becomes challenging due to the trapping of zinc in the weld molten pool, which could lead to weld defects such as porosity and liquid metal embrittlement cracks. This work focused on the weldability of AHSS (CP800 and 980HF) using the gas metal arc welding process. The roles of both galvanized iron coating and filler material on weld strength were investigated. The welds were performed using two different filler materials: a low-strength filler (ER70S-6) and a high-strength filler (ER100S-6) material. In addition, two different joint configurations were studied: lap joints and butt joints. The results showed that the butt joint had a higher strength compared to the lap joints. Furthermore, the strength of the butt joint overmatched the base material strength in all of the tested materials (both in galvanized and uncoated). In general, lap joint strength undermatched the base material strength, which was attributed to the rotation during tensile testing that induced unaccounted bending stress on the lap joint, while using a higherstrength welding wire improved the tensile strength material in the lap joint configuration. The hardness profiles in the 980HF steel also showed a significant hardness mismatch due to the formation of a fully martensitic microstructure in the heat-affected zone, which led to suppressing the deformation across the lap joint.


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