Compliance-Based Determination of Fatigue Design Curves for Elastomeric Adhesive Joints

A compliance-based method for the determination of fatigue design curves for elastomeric adhesive joints is developed and validated. Fatigue experiments are conducted on elastomeric adhesives (a polyurethane and a silane-modified polymer) under different stress ratios (R = 0.1/0.5/−1) and conditions...

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Main Authors: Pedro Henrique Evangelista Fernandes, Christof Nagel, Andreas Wulf, Vinicius Carrillo Beber, Bernd Mayer
Format: Article
Language:English
Published: MDPI AG 2023-10-01
Series:Eng
Subjects:
Online Access:https://www.mdpi.com/2673-4117/4/4/150
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author Pedro Henrique Evangelista Fernandes
Christof Nagel
Andreas Wulf
Vinicius Carrillo Beber
Bernd Mayer
author_facet Pedro Henrique Evangelista Fernandes
Christof Nagel
Andreas Wulf
Vinicius Carrillo Beber
Bernd Mayer
author_sort Pedro Henrique Evangelista Fernandes
collection DOAJ
description A compliance-based method for the determination of fatigue design curves for elastomeric adhesive joints is developed and validated. Fatigue experiments are conducted on elastomeric adhesives (a polyurethane and a silane-modified polymer) under different stress ratios (R = 0.1/0.5/−1) and conditions (23 °C/50% r.h. and 40 °C/60% r.h.). The investigation focused on butt and thick adherent shear test joints. Fatigue tests are recorded with cameras to identify the stages of crack initiation and propagation. For each fatigue test, the stiffness and compliance per cycle are calculated until final failure. The proposed method identifies a transition point that distinguishes regions under stable and unstable compliance growth. Fatigue design curves are then built based on the transition point and on the number of cycles to reach different degrees of initial stiffness (90%, 80%, 70% and 60%). The failure ratio, i.e., the lifetime for reaching a given approach divided by the total lifetime, is introduced to evaluate the data in terms of average values and standard deviation. The results indicate that the proposed method can yield fatigue design curves with a high coefficient of determination (accuracy) and high failure ratio (avoiding over-conservative design). Moreover, the method is robust, as the failure ratio for different adhesives, stress ratios, conditions and geometries is highly consistent.
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spelling doaj.art-56c39f8b167b4ff79ebd99feb1dbdbe92023-12-22T14:06:14ZengMDPI AGEng2673-41172023-10-01442615263910.3390/eng4040150Compliance-Based Determination of Fatigue Design Curves for Elastomeric Adhesive JointsPedro Henrique Evangelista Fernandes0Christof Nagel1Andreas Wulf2Vinicius Carrillo Beber3Bernd Mayer4Fraunhofer Institute for Manufacturing Technology and Advanced Materials IFAM, 28359 Bremen, GermanyFraunhofer Institute for Manufacturing Technology and Advanced Materials IFAM, 28359 Bremen, GermanyFraunhofer Institute for Manufacturing Technology and Advanced Materials IFAM, 28359 Bremen, GermanyFraunhofer Institute for Manufacturing Technology and Advanced Materials IFAM, 28359 Bremen, GermanyFraunhofer Institute for Manufacturing Technology and Advanced Materials IFAM, 28359 Bremen, GermanyA compliance-based method for the determination of fatigue design curves for elastomeric adhesive joints is developed and validated. Fatigue experiments are conducted on elastomeric adhesives (a polyurethane and a silane-modified polymer) under different stress ratios (R = 0.1/0.5/−1) and conditions (23 °C/50% r.h. and 40 °C/60% r.h.). The investigation focused on butt and thick adherent shear test joints. Fatigue tests are recorded with cameras to identify the stages of crack initiation and propagation. For each fatigue test, the stiffness and compliance per cycle are calculated until final failure. The proposed method identifies a transition point that distinguishes regions under stable and unstable compliance growth. Fatigue design curves are then built based on the transition point and on the number of cycles to reach different degrees of initial stiffness (90%, 80%, 70% and 60%). The failure ratio, i.e., the lifetime for reaching a given approach divided by the total lifetime, is introduced to evaluate the data in terms of average values and standard deviation. The results indicate that the proposed method can yield fatigue design curves with a high coefficient of determination (accuracy) and high failure ratio (avoiding over-conservative design). Moreover, the method is robust, as the failure ratio for different adhesives, stress ratios, conditions and geometries is highly consistent.https://www.mdpi.com/2673-4117/4/4/150elastomercompliancefatigue designpolyurethanesilane-modified polymer
spellingShingle Pedro Henrique Evangelista Fernandes
Christof Nagel
Andreas Wulf
Vinicius Carrillo Beber
Bernd Mayer
Compliance-Based Determination of Fatigue Design Curves for Elastomeric Adhesive Joints
Eng
elastomer
compliance
fatigue design
polyurethane
silane-modified polymer
title Compliance-Based Determination of Fatigue Design Curves for Elastomeric Adhesive Joints
title_full Compliance-Based Determination of Fatigue Design Curves for Elastomeric Adhesive Joints
title_fullStr Compliance-Based Determination of Fatigue Design Curves for Elastomeric Adhesive Joints
title_full_unstemmed Compliance-Based Determination of Fatigue Design Curves for Elastomeric Adhesive Joints
title_short Compliance-Based Determination of Fatigue Design Curves for Elastomeric Adhesive Joints
title_sort compliance based determination of fatigue design curves for elastomeric adhesive joints
topic elastomer
compliance
fatigue design
polyurethane
silane-modified polymer
url https://www.mdpi.com/2673-4117/4/4/150
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AT christofnagel compliancebaseddeterminationoffatiguedesigncurvesforelastomericadhesivejoints
AT andreaswulf compliancebaseddeterminationoffatiguedesigncurvesforelastomericadhesivejoints
AT viniciuscarrillobeber compliancebaseddeterminationoffatiguedesigncurvesforelastomericadhesivejoints
AT berndmayer compliancebaseddeterminationoffatiguedesigncurvesforelastomericadhesivejoints