Pub Date : 2024-12-01DOI: 10.1016/j.finmec.2024.100297
Tu Anh Do, Ba-Anh Le
In concrete construction, early-age thermal cracks in foundations, abutments, piers, and slabs can arise from non-uniform temperature distribution due to heat from cement hydration. These cracks negatively impact the integrity, load-bearing capacity, and service life of the concrete structures. This paper investigates the application of machine learning (ML) models to predict early-age thermal cracking in concrete bridge piers. The study aims to develop models to forecast thermal cracking potential (ηmax) and estimate the timing of potential cracking (t) based on a dataset of various cross-sectional bridge piers and typical tropical temperatures. Four ML models—Support Vector Machine (SVM), Extreme Gradient Boosting (XGB), Artificial Neural Network (ANN), and Genetic Programming (GP)—were trained on 759 samples. The dataset, prepared using the EACTSA program, included parameters like cross-sectional dimensions, ambient temperature, and initial concrete temperature, with ηmax and t as outputs. Results show that all the ML models achieved high prediction accuracy with R² scores over 0.96. The GP symbolic equations offer transparency and practical implementation. Compared to conventional methods, ML models provide a rapid, effective tool to optimize concrete member dimensions, formwork removal timing, and control concrete temperature, mitigating early-age thermal cracking risk.
{"title":"Machine learning approach for predicting early-age thermal cracking potential in concrete bridge piers","authors":"Tu Anh Do, Ba-Anh Le","doi":"10.1016/j.finmec.2024.100297","DOIUrl":"10.1016/j.finmec.2024.100297","url":null,"abstract":"<div><div>In concrete construction, early-age thermal cracks in foundations, abutments, piers, and slabs can arise from non-uniform temperature distribution due to heat from cement hydration. These cracks negatively impact the integrity, load-bearing capacity, and service life of the concrete structures. This paper investigates the application of machine learning (ML) models to predict early-age thermal cracking in concrete bridge piers. The study aims to develop models to forecast thermal cracking potential (<em>η<sub>max</sub></em>) and estimate the timing of potential cracking (<em>t</em>) based on a dataset of various cross-sectional bridge piers and typical tropical temperatures. Four ML models—Support Vector Machine (SVM), Extreme Gradient Boosting (XGB), Artificial Neural Network (ANN), and Genetic Programming (GP)—were trained on 759 samples. The dataset, prepared using the EACTSA program, included parameters like cross-sectional dimensions, ambient temperature, and initial concrete temperature, with <em>η<sub>max</sub></em> and <em>t</em> as outputs. Results show that all the ML models achieved high prediction accuracy with R² scores over 0.96. The GP symbolic equations offer transparency and practical implementation. Compared to conventional methods, ML models provide a rapid, effective tool to optimize concrete member dimensions, formwork removal timing, and control concrete temperature, mitigating early-age thermal cracking risk.</div></div>","PeriodicalId":93433,"journal":{"name":"Forces in mechanics","volume":"17 ","pages":"Article 100297"},"PeriodicalIF":3.2,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142748151","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Vacuum circuit breakers (VCBs) are widely used in the switchgear industry. Over the past decades, leading companies have conducted extensive research and development to optimize the mechanical mechanisms and understand the kinematics and dynamics behavior of VCBs. The mechanical life of these devices is crucial for safety and reliability. This paper investigates an essential component of the VCB mechanism by evaluating the stress in the cam using theoretical and numerical methods. Furthermore, the calculations are supported by examining a deformed cam in a VCB after 2500 cycles. To this end, contact stress equations for the cylindrical part of the cam and its follower were developed. The ABAQUS finite element software was employed with specified contact properties. Additionally, an image of a cam in a VCB after 2500 cycles was processed and compared to other methods. The results demonstrate that the cam exhibited alternating stress values at different local locations at the end of its profile. However, in general, the Von Mises stress increased as the location on the cam progressed from 0° to 240°.
{"title":"Theoretical and numerical stress analysis in the cam of a medium voltage switchgear vacuum circuit breaker supported by image processing of deformation","authors":"Mahmood Matin , Erfan Fatahi , Hossein Darijani , Aram Arjmand","doi":"10.1016/j.finmec.2024.100298","DOIUrl":"10.1016/j.finmec.2024.100298","url":null,"abstract":"<div><div>Vacuum circuit breakers (VCBs) are widely used in the switchgear industry. Over the past decades, leading companies have conducted extensive research and development to optimize the mechanical mechanisms and understand the kinematics and dynamics behavior of VCBs. The mechanical life of these devices is crucial for safety and reliability. This paper investigates an essential component of the VCB mechanism by evaluating the stress in the cam using theoretical and numerical methods. Furthermore, the calculations are supported by examining a deformed cam in a VCB after 2500 cycles. To this end, contact stress equations for the cylindrical part of the cam and its follower were developed. The ABAQUS finite element software was employed with specified contact properties. Additionally, an image of a cam in a VCB after 2500 cycles was processed and compared to other methods. The results demonstrate that the cam exhibited alternating stress values at different local locations at the end of its profile. However, in general, the Von Mises stress increased as the location on the cam progressed from 0° to 240°.</div></div>","PeriodicalId":93433,"journal":{"name":"Forces in mechanics","volume":"17 ","pages":"Article 100298"},"PeriodicalIF":3.2,"publicationDate":"2024-11-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142705243","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The potential challenge of delamination in fibre–metal laminates highlight the importance of improving interfacial bonding within the laminate. Developing a comprehensive understanding of the nature of this failure is essential for implementing effective mitigation strategies. This study explores fibre metal laminates comprising aluminium sheets and glass/epoxy, with and without the addition of nanoclay at varying weight percentages (0.5, 1, 1.5, and 2 wt.%). Fabrication involved the hand layup method followed by compression moulding, and the laminates were subjected to flexural, inter-laminar shear strength, and quasi-static punch shear tests (QS-PS). Two different indenters, flat and hemispheric, were employed in the QS-PS. Observations from flexural and interlaminar shear strength tests indicated that fibre metal laminate (FML) composites lacking nanoclay exhibit weakened interfacial bonding between aluminium and fibre layers. Notably, at 1.5 wt.% nanoclay, a substantial improvement in interfacial bonding between the fibre and aluminium layers improved the flexural strength (ca. 337 MPa), interfacial shear strength (ca. 16 MPa) and puncture resistance. The puncture failure modes exhibited variability based on the type of the indenter used, whether flat or hemispherical. For FML composites containing 2 wt.% nanoclay, the puncture shear strength differed significantly between the two indenters, measuring approximately 81 MPa under the flat indenter and about 49 MPa under the hemispherical indenter. Additionally, the corresponding energy absorption values were 880 KJ/g and 919 KJ/g for the flat and hemispherical indenters, respectively.
{"title":"Quasi-static puncture shear loading characteristics of GLARE/nanoclay laminates with various indenters","authors":"Thiyagu Murgaiyan , Vasudevan Alagumalai , Yoganandam Krishnamoorthy , Prem kumar , Arumugaprabu Veerasimman , Sundarakannan Rajendran , Megavannan Mani , Senthilkumar Jadamuni , Vigneshwaran Shanmugam , Oisik Das","doi":"10.1016/j.finmec.2024.100295","DOIUrl":"10.1016/j.finmec.2024.100295","url":null,"abstract":"<div><div>The potential challenge of delamination in fibre–metal laminates highlight the importance of improving interfacial bonding within the laminate. Developing a comprehensive understanding of the nature of this failure is essential for implementing effective mitigation strategies. This study explores fibre metal laminates comprising aluminium sheets and glass/epoxy, with and without the addition of nanoclay at varying weight percentages (0.5, 1, 1.5, and 2 wt.%). Fabrication involved the hand layup method followed by compression moulding, and the laminates were subjected to flexural, inter-laminar shear strength, and quasi-static punch shear tests (QS-PS). Two different indenters, flat and hemispheric, were employed in the QS-PS. Observations from flexural and interlaminar shear strength tests indicated that fibre metal laminate (FML) composites lacking nanoclay exhibit weakened interfacial bonding between aluminium and fibre layers. Notably, at 1.5 wt.% nanoclay, a substantial improvement in interfacial bonding between the fibre and aluminium layers improved the flexural strength (ca. 337 MPa), interfacial shear strength (ca. 16 MPa) and puncture resistance. The puncture failure modes exhibited variability based on the type of the indenter used, whether flat or hemispherical. For FML composites containing 2 wt.% nanoclay, the puncture shear strength differed significantly between the two indenters, measuring approximately 81 MPa under the flat indenter and about 49 MPa under the hemispherical indenter. Additionally, the corresponding energy absorption values were 880 KJ/g and 919 KJ/g for the flat and hemispherical indenters, respectively.</div></div>","PeriodicalId":93433,"journal":{"name":"Forces in mechanics","volume":"17 ","pages":"Article 100295"},"PeriodicalIF":3.2,"publicationDate":"2024-11-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142722287","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-14DOI: 10.1016/j.finmec.2024.100294
Ali Mottaghi , Ali Mokhtarian , Mohammad Hashemian , Mostafa Pirmoradian , Soheil Salahshour
This research investigates the free vibrational behavior of a functionally graded porous (FGP) nanoplate resting on an elastic Pasternak foundation in a hygrothermal environment. The nanoplate is modeled based on the nonlocal strain gradient theory (NSGT) and considering several plate theories including the CPT (classical plate theory), the FSDT (first-order shear deformation theory), and the TSDT (third-order shear deformation theory). Several patterns are investigated for the dispersion of pores, and the surface effects are incorporated to enhance the precision of the model. The governing equations and boundary conditions are derived via Hamilton's principle and an exact solution is provided via the Navier method. The impacts of several parameters on the natural frequencies are inspected such as length scale and nonlocal parameters, surface effects, porosity parameter, hygrothermal environment, and coefficients of the foundation. The results show that the impact of the porosity parameter on the natural frequencies of nanoplates is significantly dependent on the porosity distribution pattern. It is discovered that by increasing the porosity parameter from 0 to 0.6, the relative changes of natural frequencies vary from a decrease of 30 % to an increase of 6 %.
{"title":"Free vibration analysis of a functionally graded porous nanoplate in a hygrothermal environment resting on an elastic foundation","authors":"Ali Mottaghi , Ali Mokhtarian , Mohammad Hashemian , Mostafa Pirmoradian , Soheil Salahshour","doi":"10.1016/j.finmec.2024.100294","DOIUrl":"10.1016/j.finmec.2024.100294","url":null,"abstract":"<div><div>This research investigates the free vibrational behavior of a functionally graded porous (FGP) nanoplate resting on an elastic Pasternak foundation in a hygrothermal environment. The nanoplate is modeled based on the nonlocal strain gradient theory (NSGT) and considering several plate theories including the CPT (classical plate theory), the FSDT (first-order shear deformation theory), and the TSDT (third-order shear deformation theory). Several patterns are investigated for the dispersion of pores, and the surface effects are incorporated to enhance the precision of the model. The governing equations and boundary conditions are derived via Hamilton's principle and an exact solution is provided via the Navier method. The impacts of several parameters on the natural frequencies are inspected such as length scale and nonlocal parameters, surface effects, porosity parameter, hygrothermal environment, and coefficients of the foundation. The results show that the impact of the porosity parameter on the natural frequencies of nanoplates is significantly dependent on the porosity distribution pattern. It is discovered that by increasing the porosity parameter from 0 to 0.6, the relative changes of natural frequencies vary from a decrease of 30 % to an increase of 6 %.</div></div>","PeriodicalId":93433,"journal":{"name":"Forces in mechanics","volume":"17 ","pages":"Article 100294"},"PeriodicalIF":3.2,"publicationDate":"2024-11-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142705242","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This paper presents a nodal integration technique, the sub-domain stabilized conforming integration (SSCI), for the meshfree radial point interpolation method (RPIM) applied to the static and modal analysis of functionally graded material (FGM) sandwich curved shells. FGM sandwich shells with different kinds of core and face sheets are considered in this work while the interested curved shell is formulated by the first-order shear deformation theory. The numerical integration technique to compute the stiffness and mass matrices in the equilibrium equation is the SSCI, which is a stabilized nodal integration with strain smoothing to preserve the accuracy and stability of the numerical results. The RPIM shape functions are utilized in this study for interpolating both the field variables and the geometry of the curved shell due to their ability to satisfy the Kronecker delta property, a rare advantage among meshfree methods. The static and modal analysis of different geometry curved shells with various sandwich FGMs are conducted. Through several numerical examples, the accuracy and efficiency of the SSCI technique in the meshfree RPIM are demonstrated and discussed.
{"title":"Enhanced meshfree method with nodal integration for analysis of functionally graded material sandwich curved shells","authors":"Thien Tich Truong, Binh Khanh Ngo, Nha Thanh Nguyen, Vay Siu Lo","doi":"10.1016/j.finmec.2024.100292","DOIUrl":"10.1016/j.finmec.2024.100292","url":null,"abstract":"<div><div>This paper presents a nodal integration technique, the sub-domain stabilized conforming integration (SSCI), for the meshfree radial point interpolation method (RPIM) applied to the static and modal analysis of functionally graded material (FGM) sandwich curved shells. FGM sandwich shells with different kinds of core and face sheets are considered in this work while the interested curved shell is formulated by the first-order shear deformation theory. The numerical integration technique to compute the stiffness and mass matrices in the equilibrium equation is the SSCI, which is a stabilized nodal integration with strain smoothing to preserve the accuracy and stability of the numerical results. The RPIM shape functions are utilized in this study for interpolating both the field variables and the geometry of the curved shell due to their ability to satisfy the Kronecker delta property, a rare advantage among meshfree methods. The static and modal analysis of different geometry curved shells with various sandwich FGMs are conducted. Through several numerical examples, the accuracy and efficiency of the SSCI technique in the meshfree RPIM are demonstrated and discussed.</div></div>","PeriodicalId":93433,"journal":{"name":"Forces in mechanics","volume":"17 ","pages":"Article 100292"},"PeriodicalIF":3.2,"publicationDate":"2024-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142554078","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-20DOI: 10.1016/j.finmec.2024.100293
Shengrong Hu, Jingjing Xu, Xinhong Liu
A previous 8-node 24-degree-of-freedom hexahedral element H8i9 is modified to improve its performance in structures of various shapes, especially in plates and shells. First, the complicated correction coefficients for non-conforming modes required by the patch test are reduced to constant values independent of the element. Second, the element strain field is enhanced with bilinear modes by the introduction of a trilinear non-conforming mode. Third, the iterative regularization used to address the ill-conditioned stiffness matrix is replaced by a special 9-point integration rule. Benchmark tests demonstrate that the new element H8ij10 outperforms the previous version, particularly with a notable improvement in coarse-mesh accuracy in plate and shell issues.
{"title":"Improved eight-node non-conforming hexahedral element for structures of various shapes","authors":"Shengrong Hu, Jingjing Xu, Xinhong Liu","doi":"10.1016/j.finmec.2024.100293","DOIUrl":"10.1016/j.finmec.2024.100293","url":null,"abstract":"<div><div>A previous 8-node 24-degree-of-freedom hexahedral element H8i9 is modified to improve its performance in structures of various shapes, especially in plates and shells. First, the complicated correction coefficients for non-conforming modes required by the patch test are reduced to constant values independent of the element. Second, the element strain field is enhanced with bilinear modes by the introduction of a trilinear non-conforming mode. Third, the iterative regularization used to address the ill-conditioned stiffness matrix is replaced by a special 9-point integration rule. Benchmark tests demonstrate that the new element H8ij10 outperforms the previous version, particularly with a notable improvement in coarse-mesh accuracy in plate and shell issues.</div></div>","PeriodicalId":93433,"journal":{"name":"Forces in mechanics","volume":"17 ","pages":"Article 100293"},"PeriodicalIF":3.2,"publicationDate":"2024-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142528482","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-23DOI: 10.1016/j.finmec.2024.100291
H.H. Hardy
A Euler-Lagrange model of dynamic internal friction is proposed and is shown to match the frequency and decay of oscillations in both simple extension (pull) and cantilever beam experiments. The proposed dynamic internal frictional stress, , is proportional to the rate of change of the engineering stress, . i.e.with the dynamic internal friction coefficient. A single value of the dynamic internal friction coefficient is shown to match the results of the experiments for a number of different geometries of the silicon rubber, Dragon SkinTM. Dragon SkinTM is used in skin effects for movies and in prosthetics and cushioning applications. It is chosen here because of its ease of preparation and relatively simple non-linear stress-strain response. Because of these characteristics, it provides a simple starting place for simulating more complicated synthetic rubber and biological materials, which are used in a myriad of commercial applications.
{"title":"A Euler-lagrange Model of dynamic internal friction","authors":"H.H. Hardy","doi":"10.1016/j.finmec.2024.100291","DOIUrl":"10.1016/j.finmec.2024.100291","url":null,"abstract":"<div><div>A Euler-Lagrange model of dynamic internal friction is proposed and is shown to match the frequency and decay of oscillations in both simple extension (pull) and cantilever beam experiments. The proposed dynamic internal frictional stress, <span><math><msub><mi>τ</mi><mrow><mi>i</mi><mi>j</mi></mrow></msub></math></span>, is proportional to the rate of change of the engineering stress, <span><math><msub><mover><mi>σ</mi><mo>˙</mo></mover><mrow><mi>i</mi><mi>j</mi></mrow></msub></math></span>. i.e.<span><span><span><math><mrow><msub><mi>τ</mi><mrow><mi>i</mi><mi>j</mi></mrow></msub><mo>=</mo><msub><mi>μ</mi><mi>m</mi></msub><msub><mover><mi>σ</mi><mo>˙</mo></mover><mrow><mi>i</mi><mi>j</mi></mrow></msub><mo>,</mo></mrow></math></span></span></span>with <span><math><msub><mi>μ</mi><mi>m</mi></msub></math></span> the dynamic internal friction coefficient. A single value of the dynamic internal friction coefficient is shown to match the results of the experiments for a number of different geometries of the silicon rubber, Dragon Skin<sup>TM</sup>. Dragon Skin<sup>TM</sup> is used in skin effects for movies and in prosthetics and cushioning applications. It is chosen here because of its ease of preparation and relatively simple non-linear stress-strain response. Because of these characteristics, it provides a simple starting place for simulating more complicated synthetic rubber and biological materials, which are used in a myriad of commercial applications.</div></div>","PeriodicalId":93433,"journal":{"name":"Forces in mechanics","volume":"17 ","pages":"Article 100291"},"PeriodicalIF":3.2,"publicationDate":"2024-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142428408","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-15DOI: 10.1016/j.finmec.2024.100289
Minhaj Uddin Mahmood Siddique , I.M. Nazmul
This paper presents analytical solutions for the bending behavior of bi-directional functionally graded (BDFG) micro and nanobeams, wherein the material properties vary along both the thickness and axial directions, following power-law and exponential-law profiles, respectively. This study employs two size-dependent theories, nonlocal modified couple stress theory (NCST) and nonlocal strain gradient theory (NSGT), to account for size effects inherent in nanoscale structures. The governing differential equations are derived using Hamilton's principle, and the Laplace transform technique is utilized for their solution. The study critically compares the size effects captured by NCST and NSGT and assesses the influence of material gradation parameters in both directions. Additionally, the impacts of nonlocal and length scale parameters are thoroughly investigated. The findings indicate that NSGT tends to overestimate size effects compared to NCST. This research enhances the understanding of the mechanical behavior of BDFG nanobeams, offering valuable insights for the design and analysis of nanoscale structures across diverse applications.
{"title":"Static bending analysis of BDFG nanobeams by nonlocal couple stress theory and nonlocal strain gradient theory","authors":"Minhaj Uddin Mahmood Siddique , I.M. Nazmul","doi":"10.1016/j.finmec.2024.100289","DOIUrl":"10.1016/j.finmec.2024.100289","url":null,"abstract":"<div><div>This paper presents analytical solutions for the bending behavior of bi-directional functionally graded (BDFG) micro and nanobeams, wherein the material properties vary along both the thickness and axial directions, following power-law and exponential-law profiles, respectively. This study employs two size-dependent theories, nonlocal modified couple stress theory (NCST) and nonlocal strain gradient theory (NSGT), to account for size effects inherent in nanoscale structures. The governing differential equations are derived using Hamilton's principle, and the Laplace transform technique is utilized for their solution. The study critically compares the size effects captured by NCST and NSGT and assesses the influence of material gradation parameters in both directions. Additionally, the impacts of nonlocal and length scale parameters are thoroughly investigated. The findings indicate that NSGT tends to overestimate size effects compared to NCST. This research enhances the understanding of the mechanical behavior of BDFG nanobeams, offering valuable insights for the design and analysis of nanoscale structures across diverse applications.</div></div>","PeriodicalId":93433,"journal":{"name":"Forces in mechanics","volume":"17 ","pages":"Article 100289"},"PeriodicalIF":3.2,"publicationDate":"2024-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2666359724000350/pdfft?md5=2071d7bdfb7674d4acc2d527c01d7d39&pid=1-s2.0-S2666359724000350-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142311847","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In this study, a circular type honeycomb sandwich panel using natural JUCO and synthetic woven glass fiber was fabricated, and the bending properties like bending strength, modulus of rupture (MOR), and modulus of elasticity (MOE) were evaluated. Polyurethane (PU) foam was injected into the core structure to improve the bending strength. The orientation of jute and cotton fiber was varied to investigate the best stiffness and strength. In addition, twill-type JUCO fiber mat and synthetic woven glass fiber were also used to fabricate the circular type honeycomb sandwich panel. Finite element modeling was undertaken to validate the experimental results. Prior to the finite element analysis, a tensile test was carried out to determine the boundary conditions. Injecting polyurethane foam into the honeycomb core does not show any significant impact on bending properties. However, the deformation rate increased considerably by adding PU foam in the core structure. According to the results, honeycomb sandwich panels made of woven glass fiber with PU foam exhibited more homogenous deflection and bending compliance compared with others.
{"title":"Response of circular type sandwich panel using JUCO-glass fiber with PU foam under three-point bending loading","authors":"Md Shahriar Haque , Md Foisal Hossain , Muhammed Sohel Rana , Md Shafiul Ferdous","doi":"10.1016/j.finmec.2024.100290","DOIUrl":"10.1016/j.finmec.2024.100290","url":null,"abstract":"<div><p>In this study, a circular type honeycomb sandwich panel using natural <em>JUCO</em> and synthetic woven glass fiber was fabricated, and the bending properties like bending strength, modulus of rupture (<em>MOR</em>), and modulus of elasticity (<em>MOE</em>) were evaluated. Polyurethane (<em>PU</em>) foam was injected into the core structure to improve the bending strength. The orientation of jute and cotton fiber was varied to investigate the best stiffness and strength. In addition, twill-type <em>JUCO</em> fiber mat and synthetic woven glass fiber were also used to fabricate the circular type honeycomb sandwich panel. Finite element modeling was undertaken to validate the experimental results. Prior to the finite element analysis, a tensile test was carried out to determine the boundary conditions. Injecting polyurethane foam into the honeycomb core does not show any significant impact on bending properties. However, the deformation rate increased considerably by adding <em>PU</em> foam in the core structure. According to the results, honeycomb sandwich panels made of woven glass fiber with <em>PU</em> foam exhibited more homogenous deflection and bending compliance compared with others.</p></div>","PeriodicalId":93433,"journal":{"name":"Forces in mechanics","volume":"17 ","pages":"Article 100290"},"PeriodicalIF":3.2,"publicationDate":"2024-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2666359724000362/pdfft?md5=7ca57f8954aaae661ff4f20e49f8798d&pid=1-s2.0-S2666359724000362-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142240445","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-07DOI: 10.1016/j.finmec.2024.100288
Mohammed K. Dhahir, Peter Betz, Birgit Beckmann, Steffen Marx
The moment distribution method is considered one of the easiest and most reliable analysis methods. However, little attention has been given to modelling the stiffness of each member separately, as currently only one factor is being used to model all structural members without taking into account the loading conditions and curvature of the member. This can significantly influence the results when modelling columns, since unlike beams, which are usually bent in a single curvature configuration, columns can be bent in either a single or double curvature configuration. This paper presents a new set of stiffness factors to model each structural member separately depending on its boundary conditions and curvature. To validate this modification, an example concrete frame was modelled and analysed using the structural analysis software ETABS, and then the results were compared with that obtained from the standard moment distribution method and the modified moment distribution method. The results have revealed a significant enhancement in the accuracy of the obtained results when using the modified moment distribution method compared with the original moment distribution method, especially the values of the columns’ bending moments.
{"title":"An improved moment distribution method for the analysis of concrete frames","authors":"Mohammed K. Dhahir, Peter Betz, Birgit Beckmann, Steffen Marx","doi":"10.1016/j.finmec.2024.100288","DOIUrl":"10.1016/j.finmec.2024.100288","url":null,"abstract":"<div><p>The moment distribution method is considered one of the easiest and most reliable analysis methods. However, little attention has been given to modelling the stiffness of each member separately, as currently only one factor is being used to model all structural members without taking into account the loading conditions and curvature of the member. This can significantly influence the results when modelling columns, since unlike beams, which are usually bent in a single curvature configuration, columns can be bent in either a single or double curvature configuration. This paper presents a new set of stiffness factors to model each structural member separately depending on its boundary conditions and curvature. To validate this modification, an example concrete frame was modelled and analysed using the structural analysis software ETABS, and then the results were compared with that obtained from the standard moment distribution method and the modified moment distribution method. The results have revealed a significant enhancement in the accuracy of the obtained results when using the modified moment distribution method compared with the original moment distribution method, especially the values of the columns’ bending moments.</p></div>","PeriodicalId":93433,"journal":{"name":"Forces in mechanics","volume":"17 ","pages":"Article 100288"},"PeriodicalIF":3.2,"publicationDate":"2024-09-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2666359724000349/pdfft?md5=d0b8a66813b0ef9a90fe96f818bf727d&pid=1-s2.0-S2666359724000349-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142172887","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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