scholarly journals Dynamic Behavior of Self-Piercing Riveted and Mechanical Clinched Joints of Dissimilar Materials: An Experimental Comparative Investigation

2019 ◽  
Vol 2019 ◽  
pp. 1-12 ◽  
Author(s):  
Yulong Ge ◽  
Yong Xia
Keyword(s):  
Mechanical Behavior ◽  
Failure Modes ◽  
Dissimilar Materials ◽  
Dynamic Effect ◽  
Comparative Investigation ◽  
Rate Dependent ◽  
Lap Shear ◽  
Baking Process ◽  
Before And After ◽  
Peel Tests

The present work compares the dynamic effect of a self-piercing riveted (SPR) joint with that of a mechanical clinched joint having the dissimilar materials combination. The substrates used in this investigation are aluminum alloy AA5182-O and deep drawing steel DX51D+Z. The static and dynamic behaviors and the failure modes of the SPR and clinching joints are characterized by lap-shear, cross-tension, and coach-peel tests. The influence of the strain-rate-dependent mechanical behavior of the substrates on the joints is examined; this can help improve prediction of the energy absorption of the joints under impact loading. Considering the realistic baking process in a painting shop, the deforming and hardening effects on the SPR and the clinched joints induced by baking are also studied. The specimens are heated to 180°C for 30 min in an oven and then cooled down in air. The SPR and the clinched joints before and after the baking process are compared in terms of the mechanical behavior.

scholarly journals Experimental investigation of typical connections for fabricated cold-formed steel structures

2018 ◽  
Vol 22 (1) ◽  
pp. 141-155
Author(s):  
Weiming Yan ◽  
Tingting Mu ◽  
Zhiqiang Xie ◽  
Cheng Yu
Keyword(s):  
Mechanical Behavior ◽  
Failure Modes ◽  
High Efficiency ◽  
Design Method ◽  
Sheet Thickness ◽  
Steel Structures ◽  
Comparative Investigation ◽  
Lap Shear ◽  
Cold Formed Steel ◽  
European Standards

This article presents a comparative investigation on mechanical behavior and construction characteristics of some typical connections in cold-formed thin-walled steel. The lap shear tests of 96 specimens considering four typical connections with a self-piercing rivet, clinching, self-drilling screw, and blind rivet were conducted. The effects of sheet thickness and thickness ratio on failure modes and mechanical behavior of the four types of connections were investigated. Through analyzing the feasibility of mechanic and construction, the applicability of the four types of connections in fabricated cold-formed steel structures was comprehensively evaluated. The result of the research shows that compared with the other three connections, self-piercing rivet connections are more suitable for modularly fabricated cold-formed steel structures because of its superior mechanical properties, well-formed quality, high efficiency, and potential industrialization. Based on the design methods of fasteners in North American (AISI S100-16) and European standards (prEN1999-1-4) on cold-formed steel structures, an appropriate design method is proposed for self-piercing riveting connections.

Joining sheets made from dissimilar materials by hole hemming

2022 ◽  
pp. 146442072110726
Author(s):  
Mohammad Mehdi Kasaei ◽  
Lucas FM da Silva
Keyword(s):  
Mechanical Properties ◽  
Research Work ◽  
Dissimilar Materials ◽  
Element Analysis ◽  
Lightweight Structures ◽  
Lap Shear ◽  
Gradual Failure ◽  
Peel Tests ◽  
Dp780 Steel ◽  
Joining Process

This research work presents a new joining process based on the hemming process for attaching sheets made from dissimilar materials with very different mechanical properties. The process is termed ‘hole hemming’ and consists in producing a mechanical interlock between pre-drilled holes which can be made anywhere on the sheets. The process is carried out in a two-stage operation including flanging the hole of an outer sheet and bending the flange over the hole of an inner sheet. First, the joining stages and the required tools are designed. Then, the joining of DP780 steel and AA6061-T6 aluminium alloy sheets, which are applied to manufacture lightweight structures in the automotive industries, is investigated using finite element analysis. Results show that the hole hemming process is able to successfully join these materials without fracture. The hole-hemmed joint withstood the maximum forces of 2.5 and 0.5 kN in single-lap shear and peel tests, respectively, and failed with hole bearing mode which is known as a gradual failure mode. The results demonstrate the applicability of the hole hemming process for joining dissimilar materials.

Effect of stirring time on the mechanical behavior of friction stir spot weld of Al 6061-T6 lap-shear configuration

2018 ◽  
Vol 233 (10) ◽  
pp. 3583-3591 ◽  
Author(s):  
Amirreza Shahani ◽  
Ali Farrahi
Keyword(s):  
Mechanical Behavior ◽  
Failure Modes ◽  
Static Strength ◽  
High Load ◽  
Welding Condition ◽  
Friction Stir ◽  
Al 6061 ◽  
Lap Shear ◽  
Low Load ◽  
Stirring Time

The effect of five different stirring times of friction stir spot welding on lap-shear specimens of Al 6061-T6 alloy has been experimentally analyzed. The welding condition with 2 s of stirring shows the optimum mechanical behavior in comparison to the others. The static strength and fatigue behavior of the joint are justified using the microhardness profiles. The static results prove that the increase of stirring time beyond the 2 s case has little effect on improving the static strength. The fatigue results reveal two different failure modes, which are shear fracture at high load levels and transverse crack growth at low load levels. At medium load levels, although the final failure is similar to high load levels, the transverse growth of the crack outside the welding zone, just like low load levels, is also observed.

Mechanical Behaviors of Self-Piercing Riveting Joining Dissimilar Sheets

2010 ◽  
Vol 97-101 ◽  
pp. 3932-3935 ◽  
Author(s):  
Zhi Chao Huang ◽  
Ze Jie Zhou ◽  
Wei Huang
Keyword(s):  
Aluminum Alloy ◽  
Mechanical Behavior ◽  
Steel Sheet ◽  
Dissimilar Materials ◽  
Aluminum Sheet ◽  
Mechanical Behaviors ◽  
Dissimilar Metal ◽  
Lap Shear ◽  
Metal Sheets ◽  
Cross Tension

This paper summarizes riveting tests and mechanical behaviors of Self-piercing Riveting (SPR) with semi-tubular rivet joining dissimilar metal sheets. The tests joining 2A12 aluminum sheet and DC01 steel sheet are carried out in lap-shear, coach-peel and cross-tension joint styles. The results show that SPR joining dissimilar materials of steel and aluminum alloy is feasible and riveting joints take on high mechanical behavior.

Classification of Failure Modes in Friction Stir Blind Riveted Lap-Shear Joints With Dissimilar Materials

2016 ◽  
Vol 139 (2) ◽  
Author(s):  
Wei-Ming Wang ◽  
Haris Ali Khan ◽  
Jingjing Li ◽  
Scott F. Miller ◽  
A Zachary Trimble
Keyword(s):  
Failure Modes ◽  
Dissimilar Materials ◽  
Polymeric Composite ◽  
Tensile Tests ◽  
Great Promise ◽  
Lightweight Structures ◽  
Friction Stir ◽  
Lap Shear ◽  
Transportation Sector ◽  
Static Tensile

In transportation sector, there is an increasing need for joining dissimilar materials for lightweight structures; however, substantial barriers to the joining of dissimilar materials have led to an investigation and development of new joining techniques. Friction stir blind riveting (FSBR), a newly invented method, has shown great promise in joining complex structures with dissimilar materials. The process can be utilized more effectively if knowledge regarding the failure mechanisms of the FSBR joints becomes available. This research focuses on investigating the different mechanisms that lead to a failure in FSBR joints under lap-shear tensile tests. An in situ, nondestructive, acoustic emission (AE) testing method was applied during quasi-static tensile tests to monitor the initiation and evolution of damage in FSBR joints with different combinations of dissimilar materials (including aluminum, magnesium, and a carbon-fiber reinforced polymeric composite). In addition, a fractographic analysis was conducted to characterize the failure modes. Finally, based on the analysis, the distinct failure modes and damage accumulation processes for the joints were identified. An AE accumulative hit history curve was found to be efficient to discriminate the deformation characteristics, such as the deformation zone and failure mode, which cannot be observed through a traditional extensometer measurement method. In addition, the AE accumulative hit history curve can be applied to predict the failure extension or moment of FSBR joints through an identification of the changes in curve slope. Such slope changes usually occur around the middle of Zone II, which is defined in this study.

Performance Prediction for Ultrasonically Welded Dissimilar Materials Joints

2016 ◽  
Vol 139 (1) ◽  
Author(s):  
Liang Xi ◽  
Mihaela Banu ◽  
S. Jack Hu ◽  
Wayne Cai ◽  
Jeffrey Abell
Keyword(s):  
Failure Modes ◽  
Mechanical Performance ◽  
Welding Process ◽  
Dissimilar Materials ◽  
Lithium Ion ◽  
Microscopic Analysis ◽  
Lap Shear ◽  
Physical Attributes ◽  
Assembly Operations ◽  
Metal Welding

Ultrasonic metal welding has been used to join multiple layers of battery tabs with the bus bar in lithium-ion battery assembly operations. This paper describes joint performance models for ultrasonic metal welds of multiple layers of dissimilar battery tab materials, i.e., aluminum and copper. Finite element (FE) models are developed to predict the mechanical performance of the ultrasonically welded joints. The models predict peak shear load, energy absorption capability, and failure modes, which are necessary for modeling product performance and defining process requirements for the welds. The models can be adjusted to represent different quality of welds created in conditions of underweld (UW), normal-weld (NW), or overweld (OW) using physical attributes observed through microscopic analysis. The models are validated through lap shear tests, which demonstrate excellent agreement for the maximum force in the NW condition and good agreement for the UW and OW conditions. The models provide in-depth understanding of the relationship among welding process parameters, physical weld attributes, and the weld performance. The models also provide significant insight for further development of ultrasonic welding process for battery tabs and help optimize welding process for more than four-layered joints.

Evaluation of Freezing Methods by Low Temperature X-Ray Diffraction

1977 ◽  
Vol 35 ◽  
pp. 330-333
Author(s):  
T. Gulik-Krzywicki ◽  
M.J. Costello
Keyword(s):  
Biological Materials ◽  
Molecular Organization ◽  
X Ray Diffraction ◽  
Glass Capillary ◽  
X Ray ◽  
Rate Dependent ◽  
Before And After ◽  
Freeze Etching ◽  
Diffraction Patterns ◽  
Set Up

Freeze-etching electron microscopy is currently one of the best methods for studying molecular organization of biological materials. Its application, however, is still limited by our imprecise knowledge about the perturbations of the original organization which may occur during quenching and fracturing of the samples and during the replication of fractured surfaces. Although it is well known that the preservation of the molecular organization of biological materials is critically dependent on the rate of freezing of the samples, little information is presently available concerning the nature and the extent of freezing-rate dependent perturbations of the original organizations. In order to obtain this information, we have developed a method based on the comparison of x-ray diffraction patterns of samples before and after freezing, prior to fracturing and replication.Our experimental set-up is shown in Fig. 1. The sample to be quenched is placed on its holder which is then mounted on a small metal holder (O) fixed on a glass capillary (p), whose position is controlled by a micromanipulator.

scholarly journals Algorithmic prediction of failure modes in healthcare

2020 ◽  
Author(s):  
Ayala Kobo-Greenhut ◽  
Ortal Sharlin ◽  
Yael Adler ◽  
Nitza Peer ◽  
Vered H Eisenberg ◽  
...  
Keyword(s):  
Adverse Events ◽  
Failure Modes ◽  
Medical Center ◽  
Hazard Analysis ◽  
Working Hours ◽  
Hazard Identification ◽  
Patient Identification ◽  
Complete Identification ◽  
Before And After ◽  
Fmea Method

Abstract Background Preventing medical errors is crucial, especially during crises like the COVID-19 pandemic. Failure Modes and Effects Analysis (FMEA) is the most widely used prospective hazard analysis in healthcare. FMEA relies on brainstorming by multi-disciplinary teams to identify hazards. This approach has two major weaknesses: significant time and human resource investments, and lack of complete and error-free results. Objectives To introduce the algorithmic prediction of failure modes in healthcare (APFMH) and to examine whether APFMH is leaner in resource allocation in comparison to the traditional FMEA and whether it ensures the complete identification of hazards. Methods The patient identification during imaging process at the emergency department of Sheba Medical Center was analyzed by FMEA and APFMH, independently and separately. We compared between the hazards predicted by APFMH method and the hazards predicted by FMEA method; the total participants’ working hours invested in each process and the adverse events, categorized as ‘patient identification’, before and after the recommendations resulted from the above processes were implemented. Results APFMH is more effective in identifying hazards (P < 0.0001) and is leaner in resources than the traditional FMEA: the former used 21 h whereas the latter required 63 h. Following the implementation of the recommendations, the adverse events decreased by 44% annually (P = 0.0026). Most adverse events were preventable, had all recommendations been fully implemented. Conclusion In light of our initial and limited-size study, APFMH is more effective in identifying hazards (P < 0.0001) and is leaner in resources than the traditional FMEA. APFMH is suggested as an alternative to FMEA since it is leaner in time and human resources, ensures more complete hazard identification and is especially valuable during crisis time, when new protocols are often adopted, such as in the current days of the COVID-19 pandemic.

Microstructure and Mechanical Properties of Ti-6Al-4V Manufactured by SLM

2015 ◽  
Vol 651-653 ◽  
pp. 677-682 ◽  
Author(s):  
Anatoliy Popovich ◽  
Vadim Sufiiarov ◽  
Evgenii Borisov ◽  
Igor Polozov
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Phase Composition ◽  
Mechanical Behavior ◽  
Ductile Fracture ◽  
Elevated Temperatures ◽  
Initial Material ◽  
Laser Melting ◽  
Microstructure And Mechanical Properties ◽  
Before And After

The article presents results of a study of phase composition and microstructure of initial material and samples obtained by selective laser melting of titanium-based alloy, as well as samples after heat treatment. The effect of heat treatment on microstructure and mechanical properties of specimens was shown. It was studied mechanical behavior of manufactured specimens before and after heat treatment at room and elevated temperatures as well. The heat treatment allows obtaining sufficient mechanical properties of material at room and elevated temperatures such as increase in ductility of material. The fractography of samples showed that they feature ductile fracture with brittle elements.

scholarly journals A Material Model for the Orthotropic and Viscous Behavior of Separators in Lithium-Ion Batteries under High Mechanical Loads

Energies ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4585
Author(s):  
Marian Bulla ◽  
Stefan Kolling ◽  
Elham Sahraei
Keyword(s):  
Mechanical Behavior ◽  
Lithium Ion ◽  
Material Model ◽  
Tensile Tests ◽  
Element Analysis ◽  
Rate Dependent ◽  
Novel Material ◽  
Li Ion ◽  
Role Based ◽  
Drive Systems

The present study is focused on the development of a material model where the orthotropic-visco-elastic and orthotropic-visco-plastic mechanical behavior of a polymeric material is considered. The increasing need to reduce the climate-damaging exhaust gases in the automotive industry leads to an increasing usage of electric powered drive systems using Lithium-ion (Li-ion) batteries. For the safety and crashworthiness investigations, a deeper understanding of the mechanical behavior under high and dynamic loads is needed. In order to prevent internal short circuits and thermal runaways within a Li-ion battery, the separator plays a crucial role. Based on results of material tests, a novel material model for finite element analysis (FEA) is developed using the explicit solver Altair Radioss. Based on this model, the visco-elastic-orthotropic, as well as the visco-plastic-orthotropic, behavior until failure can be modeled. Finally, a FE simulation model of the separator material is performed, using the results of different tensile tests conducted at three different velocities, 0.1 mm·s−1, 1.0 mm·s−1 and 10.0 mm·s−1 and different orientations of the specimen. The purpose is to predict the anisotropic, rate-dependent stiffness behavior of separator materials in order to improve FE simulations of the mechanical behavior of batteries and therefore reduce the development time of electrically powered vehicles and consumer goods. The present novel material model in combination with a well-suited failure criterion, which considers the different states of stress and anisotropic-visco-dependent failure limits, can be applied for crashworthiness FE analysis. The model succeeded in predicting anisotropic, visco-elastic orthotropic and visco-plastic orthotropic stiffness behavior up to failure.

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