Effect of bolt tightening on the fatigue behavior of GLARE double shear lap joints

2021 ◽  
pp. 002199832110033
Author(s):  
B Abazadeh ◽  
HR Maleki
Keyword(s):  
Fatigue Life ◽  
Fatigue Behavior ◽  
Fatigue Tests ◽  
Lap Joints ◽  
Clamping Force ◽  
Test Results ◽  
Load Range ◽  
Double Shear ◽  
Aluminum Sheets ◽  
Aluminum Alloy 2024

In this paper, the effect of bolt torque tightening has been investigated on the fatigue behavior of GLARE in double shear lap configuration. To do so, experimental fatigue tests were conducted using GLARE3-5/4-0.4 specimens with applied torques of 0 (finger tightened), 2 and 4 Nm at different cyclic longitudinal load ranges to achieve the stress-life (S-N) curves. The results revealed that applying and increasing the clamping force enhances the fatigue life of the GLARE specimens. Furthermore, comparison of fatigue test results of GLARE and available monolithic aluminum alloy 2024-T3 plates indicated when the applied load range is low, the effect of clamping force is more noticeable in GLARE specimens due to longer fatigue crack growth life of GLARE. Also, the occurrence of fretting fatigue didn’t reduce the fatigue life of GLARE specimens considerably in contrary to aluminum sheets because of the laminated structure of GLARE. The obtained results can provide insights in designing bolted GLARE joints with superior fatigue in-service performance.

High-cycle fatigue tests of pretensioned concrete beams

PCI Journal ◽  
2022 ◽  
Vol 67 (1) ◽  
Author(s):  
Jörn Remitz ◽  
Martin Empelmann
Keyword(s):  
Fatigue Life ◽  
High Cycle Fatigue ◽  
Concrete Beams ◽  
Fatigue Behavior ◽  
Fatigue Tests ◽  
Design Methods ◽  
Test Results ◽  
Cycle Fatigue ◽  
Pretensioned Concrete ◽  
Current Design

Pretensioned concrete beams are widely used as bridge girders for simply supported bridges. Understanding the fatigue behavior of such beams is very important for design and construction to prevent fatigue failure. The fatigue behavior of pretensioned concrete beams is mainly influenced by the fatigue of the prestressing strands. The evaluation of previous test results from the literature indicated a reduced fatigue life in the long-life region compared with current design methods and specifications. Therefore, nine additional high-cycle fatigue tests were conducted on pretensioned concrete beams with strand stress ranges of about 100 MPa (14.5 ksi). The test results confirmed that current design methods and specifications overestimate the fatigue life of embedded strands in pretensioned concrete beams.

Effect of Interference-Fit on Fatigue Life for Composite Lap Joints

2014 ◽  
Vol 939 ◽  
pp. 39-46 ◽  
Author(s):  
Hong Qian Xue ◽  
Qian Tao ◽  
Emin Bayraktar
Keyword(s):  
Finite Element ◽  
Fatigue Life ◽  
Fatigue Tests ◽  
Lap Joints ◽  
Finite Element Simulations ◽  
Cyclic Loads ◽  
Lap Joint ◽  
Interference Fit ◽  
3D Finite Element ◽  
Double Shear

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.

scholarly journals Fatigue behavior of 316L austenitic stainless steel in air and LWR environment with and without mean stress

2018 ◽  
Vol 165 ◽  
pp. 03012 ◽  
Author(s):  
Wen Chen ◽  
Philippe Spätig ◽  
Hans-Peter Seifert
Keyword(s):  
Stainless Steel ◽  
Fatigue Life ◽  
Austenitic Stainless Steel ◽  
Fatigue Limit ◽  
Fatigue Behavior ◽  
Cyclic Hardening ◽  
Fatigue Tests ◽  
Mean Stress ◽  
Test Results ◽  
316L Austenitic Stainless Steel

The fatigue life design curves in nuclear codes are generally derived from uniaxial straincontrolled fatigue test results. Evidently, the test conditions are very different from the actual components loading context, which involves much more complex thermo-mechanical loading including mean stress, static load holding time and variation in water chemistry, etc. In this work, the mean stress and environmental effects on fatigue life of 316L austenitic stainless steel in air and light water reactor (LWR) environment were studied using hollow fatigue specimens and testing under load-controlled condition. Both positive (+50 MPa) and negative (-20 MPa) mean stresses showed beneficial effect on fatigue life in LWR environment and in air. This is tentatively attributed to mean stress enhanced cyclic hardening, which leads to smaller strain response at the same loading force. -20 MPa mean stress was found to increase fatigue limit, whereas the effect of +50 MPa mean stress on fatigue limit is still unclear. The preliminary results illustrate that the environmental reduction of fatigue life is amplified in load-controlled fatigue tests with tensile mean stress.

The effect of welding direction in the fatigue life of aluminium FS welded lap joints

2015 ◽  
Vol 6 (6) ◽  
pp. 775-786 ◽  
Author(s):  
F.F. Duarte ◽  
Virgínia Isabel V. Infante ◽  
P.M.G. Moreira ◽  
M. de Freitas ◽  
P.M.S.T. de Castro
Keyword(s):  
Fatigue Life ◽  
Fatigue Behavior ◽  
Decisive Role ◽  
Fatigue Tests ◽  
Lap Joints ◽  
Content Type ◽  
Loading Direction ◽  
Line Parallel ◽  
Welding Line ◽  
Number Of Cycles

Purpose – Friction stir welding lap joints of aluminum alloy AA6082-T6 were joined using two distinct configurations. The purpose of this paper is to study the effect of the welding line direction on the fatigue life of the specimens. For that purpose, specimens with the welding line parallel to the loading direction and with the welding line perpendicular to the loading direction were designed and manufactured. Fatigue tests were performed under constant amplitude load and stress ratio of R=0.1. As shown in previous studies, the hook defect plays a decisive role in the mechanical behavior of the joint, in particular when submitted to fatigue. The specimen geometry with the welding line parallel to the loading direction showed a superior fatigue behavior: for a given number of cycles to rupture, the level of stress is approximately twice as high as for the perpendicular configuration. Design/methodology/approach – Two finite element models were created in order to study the behavior of the welded zone and, in particular, to compare influence of the hook defect in both configurations. Findings – The specimen geometry with the welding line parallel to the loading direction showed a superior fatigue behavior: for a given number of cycles to rupture, the level of stress is approximately twice as high as for the perpendicular configuration. Originality/value – The main objective of this work is to study the effect of the welding line direction on the fatigue life of the specimens. For that purpose, specimens with the welding line parallel to the loading direction and with the welding line perpendicular to the loading direction were designed and manufactured. Fatigue tests were performed under constant amplitude load and stress ratio of R=0.1. As shown in previous studies, the hook defect plays a decisive role in the mechanical behavior of the joint, in particular when submitted to fatigue.

Fatigue behavior of interference fitted Al-alloy 7075-T651 specimens subjected to bolt tightening

2018 ◽  
Vol 233 (9) ◽  
pp. 1879-1893
Author(s):  
H Taghizadeh ◽  
TN Chakherlou
Keyword(s):  
Finite Element ◽  
Fatigue Life ◽  
Fatigue Test ◽  
Failure Modes ◽  
Fatigue Behavior ◽  
Fatigue Tests ◽  
Al Alloy ◽  
Clamping Force ◽  
Interference Fit ◽  
Test Behavior

Interference fit process is extensively used in bolted and pined joints having different fatigue behavior compared to plain hole specimens. In the present research, fatigue behavior of interference fitted specimens subjected to bolt clamping force has been investigated. The objective of the present study is to extend the present knowledge about the fatigue behavior of interference fitted holes by investigating the subsequent bolt clamping force effect based on the experimental and numerical results in Al-alloy 7075-T651 plates. To investigate the effect of bolt tightening on the fatigue life of interference fitted specimens two tightening torque levels were employed. Fatigue tests were performed to obtain S–N curves and failure modes of interference fitted bolt clamped specimens. Circumferential pre-stress distribution created by interference fit and bolt clamping has been analyzed by finite element method. The finite element analyses justify the experimentally observed fatigue test behavior. The fatigue test results demonstrate that bolt clamping force applied on interference fit plays a positive effect on fatigue behavior and prolongs the fatigue life.

scholarly journals Analysis of the Correlation between the Static and Fatigue Test Results of the Interlayer Bondings of Asphalt Layers

2016 ◽  
Vol 62 (1) ◽  
pp. 83-98 ◽  
Author(s):  
A. Szydło ◽  
K. Malicki
Keyword(s):  
Fatigue Life ◽  
Fatigue Test ◽  
Asphalt Mixture ◽  
Fatigue Tests ◽  
Test Results ◽  
Static Tests ◽  
Bonding State ◽  
Road Pavement ◽  
The Future ◽  
Pavement Structure

Abstract The bonding state of the asphalt layers in a road pavement structure significantly affects its fatigue life. These bondings, therefore, require detailed tests and optimization. In this paper, the analyses of the correlation between the results of laboratory static tests and the results of fatigue tests of asphalt mixture interlayer bondings were performed. The existence of the relationships between selected parameters was confirmed. In the future, the results of these analyses may allow for assessment of interlayer bondings’ fatigue life based on the results of quick and relatively easy static tests.

scholarly journals Changing in Fatigue Life of 300 M Bainitic Steel After Laser Carburizing and Plasma Nitriding

2018 ◽  
Vol 165 ◽  
pp. 21002 ◽  
Author(s):  
Antonio J. Abdalla ◽  
Douglas Santos ◽  
Getúlio Vasconcelos ◽  
Vladimir H. Baggio-Scheid ◽  
Deivid F. Silva
Keyword(s):  
Mechanical Properties ◽  
Fatigue Life ◽  
Plasma Nitriding ◽  
Fatigue Behavior ◽  
High Strength ◽  
Tensile Tests ◽  
Steel Sample ◽  
Fatigue Tests ◽  
300M Steel ◽  
Structural Applications

In this work 300M steel samples is used. This high-strength steel is used in aeronautic and aerospace industry and other structural applications. Initially the 300 M steel sample was submitted to a heat treatment to obtain a bainític structure. It was heated at 850 °C for 30 minutes and after that, cooled at 300 °C for 60 minutes. Afterwards two types of surface treatments have been employed: (a) using low-power laser CO2 (125 W) for introducing carbon into the surface and (b) plasma nitriding at a temperature of 500° C for 3 hours. After surface treatment, the metallographic preparation was carried out and the observations with optical and electronic microscopy have been made. The analysis of the coating showed an increase in the hardness of layer formed on the surface, mainly, among the nitriding layers. The mechanical properties were analyzed using tensile and fatigue tests. The results showed that the mechanical properties in tensile tests were strongly affected by the bainitic microstructure. The steel that received the nitriding surface by plasma treatment showed better fatigue behavior. The results are very promising because the layer formed on steel surface, in addition to improving the fatigue life, still improves protection against corrosion and wear.

On the Effect of Electrodischarge Drilling on the Fatigue Life of Inconel 718

2014 ◽  
Vol 891-892 ◽  
pp. 1451-1456
Author(s):  
Elena Bassoli ◽  
Andrea Baldini ◽  
Andrea Gatto ◽  
Antonio Strozzi ◽  
Lucia Denti
Keyword(s):  
Fatigue Life ◽  
Inconel 718 ◽  
Metal Cutting ◽  
Fatigue Behavior ◽  
Fatigue Tests ◽  
Aerospace Applications ◽  
Rotating Bending Fatigue ◽  
Cutting Operation ◽  
Rotating Bending ◽  
Superposition Effect

Difficult-to cut-materials are associated with premature tool failure, most likely in the case of complex geometries and this shapes. However, Nickel-based alloys are commonly used in high-temperature and aerospace applications, where thin deep holes are often required. Then, the only viable manufacturing solution relies on non-contact processes, like electrodischarge (ED) drilling. Morphology of ED machined surfaces is significantly different than obtained by metal-cutting operation and is known to jeopardize fatigue strength, but the extent needs to be gauged and related to the process parameters. Aim of the paper is to study the effect of holes (0.8 mm diameter, aspect ratio 10) produced by ED drilling on the fatigue life of Inconel 718. Rotating bending fatigue tests are carried out on specimens drilled under two ED setups, as well as with a traditional cutting tool. Specimens free from holes are fatigued under the same conditions for comparison. Based on previous studies, extremal ED parameters are selected, giving best surface finish versus highest productivity. S-N curves show that the ED process causes a decrease of the fatigue resistance with respect to traditional drilling, whereas the effect of different ED setups is negligible. Maximum productivity can thus be pursued with no threat to fatigue performance. The fatigue limit variation is quantified by using the superposition effect principle: ED drilling causes an increase of the stress concentration factor around 25% if compared to traditional drilling. The macroscopic fatigue behavior is integrated with a study of the effects of the different drilling processes in the micro-scale, by means of a microstructural and fractographic analysis.

Sign in / Sign up

Export Citation Format

Share Document