Volume 3: Advanced Materials: Design, Processing, Characterization and Applications; Advances in Aerospace Technology最新文献

{"title":"Prediction of Sectional Collapse of Thin-Walled Structure Under Pure Bending by Nonlinear Composite Beam Theory","authors":"F. Jiang, Wenbin Yu","doi":"10.1115/imece2022-96539","DOIUrl":"https://doi.org/10.1115/imece2022-96539","url":null,"abstract":"\u0000 Brazier [1] found that when one dimension of the beam cross-section was relatively smaller than the others, large in-plane displacements over the cross-section might occur, even though the strains could remain very small. Under this circumstance, the so-called Brazier effect refers to the cross-sectional ovalization, which leads to nonlinear bending buckling and collapses. This paper extends the Variational Asymptotic Beam Sectional Analysis (VABS) theory to consider finite cross-sectional deformations. The three-dimensional (3D) continuum is reduced to a one-dimensional (1D) beam analysis and a two-dimensional (2D) cross-sectional analysis featuring both geometric and material nonlinearities without unnecessary kinematic assumptions. The present theory is implemented using the finite element method (FEM) in the VABS code, a general-purpose beam cross-sectional analysis tool. An iterative method is applied to solve the finite warping field for the classical-type model using the Euler-Bernoulli beam theory. The deformation gradient tensor is directly used to deal with finite deformation, various strain definitions, and several types of material laws regarding nonlinear elasticity and progressive damage. Numerical examples demonstrate the capabilities of VABS to predict the sectional collapse of thin-walled structures under pure bending.","PeriodicalId":146276,"journal":{"name":"Volume 3: Advanced Materials: Design, Processing, Characterization and Applications; Advances in Aerospace Technology","volume":"291 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122298427","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"On the Micromechanical Properties of Conventional and 3D-Printed Rebar","authors":"S. Allameh, Alexis Eckart, Jose Fonseca Lopez, Roger A. Miller, Avery Lenihan, H. Allameh","doi":"10.1115/imece2022-94651","DOIUrl":"https://doi.org/10.1115/imece2022-94651","url":null,"abstract":"\u0000 This study is focused on the micromechanical properties of conventional rebar and how they could be used for comparison with the 3D printed rebar tensile and fatigue properties. Current trends in additive manufacturing hint at the eventual use of 3D printing in the construction of homes and office buildings. Nowadays, 3D printing of homes is being achieved on an experimental basis by depositing extruded concrete in layers up to the ceiling to make walls, and then building a roof on top of the walls by conventional methods. This practice is not suitable to make bridges, multistory office buildings or structures that substantially experience tensile stresses. It is necessary to incorporate steel rebar in otherwise easily printed concrete structures. One way to achieve this is direct welding of steel into concrete by mounting a welder gun on to the 3D printing head and conducting 3D welding of the rebar. This has been accomplished and mild steel weldments have been 3D welded onto concrete. To make it acceptable for construction, the reliability of such printed rebar must be investigated. Early results of microscale tensile and fatigue testing on steel weldments made by additive manufacturing show desirable mechanical properties. However, the comparison has been made with macroscale tensile and fatigue properties of conventional rebar. To ascertain the reliability of 3D printed rebar welded onto concrete, it is essential to conduct a comparison with the micromechanical properties of conventional mild steel rebar. To achieve this, micro-specimens were machined off thick and thin conventional rebar in various orientations including along and across the longitudinal axis of the rebar and at different depths from the surface to investigate their micromechanical properties. Dog-bone shaped specimens 1000-micron in gage length with square gage cross sections measuring 200-micron × 200-micron were extracted from the surface as well as from the center of thick and thin rebar rods using a HAAS CNC. Samples were polished to a mirror finish and then tested in an Instron Electropulse E1000 load frame equipped with microgrippers that allowed monotonic and cyclic loading of the samples at a frequency of 50Hz. The results of micromechanical testing obtained from conventional rebar are compared with the those obtained from testing micro-specimens machined from mild steel weldments deposited by 3D welding on ceramics. The results demonstrate the reliability of mild streel rebar printed by 3D welding onto concrete. The implications of the findings on the use of additive manufacturing in 3D printing reinforced concrete and how it will impact the construction industry are discussed.","PeriodicalId":146276,"journal":{"name":"Volume 3: Advanced Materials: Design, Processing, Characterization and Applications; Advances in Aerospace Technology","volume":"167 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122638739","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Body Armor - Current and Potential Materials","authors":"Nishant Thakkar, D. Piovesan, Scott E. Steinbrink","doi":"10.1115/imece2022-96207","DOIUrl":"https://doi.org/10.1115/imece2022-96207","url":null,"abstract":"\u0000 Military forces have faced the ballistic threat in many forms for hundreds of years, ranging from spears to bomb fragmentation. Soldiers have historically worn body armor to protect themselves on the battlefield. The goal of modern lightweight body armor development has always been to develop lighter and stronger materials so that performance can be improved while reducing weight and making the mobility of the personnel easy. Body armor ballistic testing follows strict guidelines provided by the National Institute of Justice (NIJ) in the United States of America. According to the new testing standards, innovative products are being released. This review elaborates on various materials and composites that are being used in the making of body armor that eventually help eliminate the threats from high-velocity bullets, shell fragments, and knives. In this paper, the science of body armor materials is quickly reviewed with emphasis on current knowledge of relevant energy-absorbing mechanisms in fibers, fabrics, polymeric laminates, and ceramics. The drive to create lightweight and comfortable armor systems for military personnel has led to the development of various composite materials. The paper reviews the major features of materials used in body armor and focuses on the development of intriguing new potential materials.","PeriodicalId":146276,"journal":{"name":"Volume 3: Advanced Materials: Design, Processing, Characterization and Applications; Advances in Aerospace Technology","volume":"520 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132488939","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Vision-Based Autonomous Inspection of Vertical Structures Using Unmanned Aerial Vehicle (UAV)","authors":"Ayush Gupta, Amit Shukla, Amit Kumar, Ashok Kumar Shivratri","doi":"10.1115/imece2022-95698","DOIUrl":"https://doi.org/10.1115/imece2022-95698","url":null,"abstract":"\u0000 High-rise structures like a chimney, flare stacks, storage tanks, cooling towers, electric line poles, and communication towers become a vital part of any industry and are very common in day-to-day life. These vertical structures required a proper and frequent inspection to run the industries safely and stay profitable. The inspection of the industrial structure is done in several stages, and vision-based inspection is the very initial, oldest, and simplest method to detect and locate the surface defects and anomalies. The existing traditional methods of vision-based inspections are unsafe, time-consuming, and are an extra financial burden on a company and the existing robotics inspections methods are ineffective, slow, and exhausting due to complex dynamics, structure, and weights. In this research work, we are proposing a fully autonomous visual inspection approach to inspect the vertical structure using aquadcopter. The unmanned aerial vehicle (UAV) equipped with cameras and non-contact sensors is simulated with the help of robot operating systems (ROS) and a visualization tool gazebo. To examine the developed algorithms, a simple black-colored cylindrical vertical structure is prepared in the gazebo. Here, the UAV first detects and locates the vertical structure in the image frame using a classical computer vision algorithm and will extract some desired features. The feature information coming out from the image frame will be fed into the heuristically tuned control algorithms for navigating and positioning the UAV around the vertical structure. For this work, offset control and width/radius of rotation control algorithms have been developed for positioning and trajectory tracking. Due to the image frame localization and positioning, the GPS dependency is not there, and it can operate in GPS denied the environment also. The simulation results are quite satisfying, and the overall performance of the computer vision algorithms and control algorithms is satisfactory.","PeriodicalId":146276,"journal":{"name":"Volume 3: Advanced Materials: Design, Processing, Characterization and Applications; Advances in Aerospace Technology","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115596657","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Thermo-Mechanical Behavior of Multi-Layer Deposition for Wire Arc Additive Manufacturing of Structural Steel: Wire Arc Additive Manufacturing","authors":"Amritesh Kumar, S. Bag, V. Srivastava, M. Amin","doi":"10.1115/imece2022-88917","DOIUrl":"https://doi.org/10.1115/imece2022-88917","url":null,"abstract":"\u0000 Wire arc additive manufacturing (WAAM) process, following the directed energy deposition (DED) technique, has evolved as one of the most prominent additive manufacturing (AM) technologies to fabricate large and intricate shapes of metallic components. The physical basis of the WAAM process is associated with rapid heating, melting, layer-by-layer melt deposition, solidification, and moderate cooling rate of the fabricated part. Consequently, different regions of the additive manufactured part experience variable heating and cooling cycles due to repeated heating and cooling. The continuously varying transient thermal cycles lead to residual stresses and distortion in fabricated components, mainly influenced by the temperature gradient along the build direction. The generation of residual stress and distortion result in warping, delamination, and unfavorable fatigue properties of the AM components. The in-situ prediction of transient temperature profile and its impact on residual stresses in an arc-based DED technique is practically impossible by any contact measurement technologies. As the cooling or idle times between the successively deposited layers play a significant role in the thermomechanical behavior of as-deposited materials, the inclination towards developing a numerical model by considering different process variants in the layer-by-layer deposition process is evolving. In the present work, a finite-element-based thermo-mechanical 3D model is developed for the WAAM process by triggering the effect of the inter-pass cooling period. The model results are validated with experiments reported in independent literature. Increasing the inter-layer dwell time decreases built material’s peak temperature and residual stress. At the same time, the distribution of effective stress along the built material’s center line increases with idle times.","PeriodicalId":146276,"journal":{"name":"Volume 3: Advanced Materials: Design, Processing, Characterization and Applications; Advances in Aerospace Technology","volume":"93-C 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121580425","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Nonlinear Transient Response of Isotropic and Composite Structures With Variable Kinematic Beam and Plate Finite Elements","authors":"R. Azzara, M. Filippi, A. Pagani, E. Carrera","doi":"10.1115/imece2022-94973","DOIUrl":"https://doi.org/10.1115/imece2022-94973","url":null,"abstract":"\u0000 The present research deals with the evaluation of nonlinear transient responses of several isotropic and composite structures with variable kinematic one-dimensional (1D) beam and two-dimensional (2D) plate finite elements with different initial deflection configurations. The aim of current investigations is to show the effect of large amplitudes and the need to adopt an accurate model to capture the correct solution. Particular attention is focused on detailed stress state distribution over time and in the thickness direction. The proposed nonlinear approach is formulated in the framework of the well-established Carrera Unified Formulation (CUF). The formalism enables one to consider the three-dimensional (3D) form of displacement-strain relations and constitutive law. In detail, different geometrical nonlinear strains from the full Green-Lagrange (GL) to the classical von Kármán (vK) models are automatically and opportunely obtained by adopting the CUF due to its intrinsic scalable nature. The Hilber-Hughes-Taylor (HHT)-α algorithm and the iterative Newton-Raphson method are employed to solve the geometrical nonlinear equations derived in a total Lagrangian domain. Both Lagrange (LE) and Taylor (TE) expansions are considered for developing the various kinematic models. The solutions are compared with results found in available literature or obtained using the commercial code Abaqus. The results demonstrated the validity of the proposed formulation and the need to adopt a full Green-Lagrange model in order to describe the highly nonlinear dynamic response and an Layerwise (LW) approach to accurately evaluate the stress distribution.","PeriodicalId":146276,"journal":{"name":"Volume 3: Advanced Materials: Design, Processing, Characterization and Applications; Advances in Aerospace Technology","volume":"10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115091606","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Statistical Analysis of Strain Rate Dependency of the Mechanical Properties of Unidirectional CFRE Materials","authors":"C. Seif, I. Hage, Ré-Mi S. Hage, A. Baydoun, R. Hamade","doi":"10.1115/imece2022-94402","DOIUrl":"https://doi.org/10.1115/imece2022-94402","url":null,"abstract":"\u0000 With the aim of finding new materials having high stiffness to density ratio, carbon fiber composite materials have gained popularity as alternatives to traditional high-stiffness and high-density materials. This work investigates the dependency on strain rate of some mechanical properties of unidirectional carbon fiber reinforced epoxy, CFRE. The composite laminates were fabricated at fiber orientations of 0° (dubbed type 1) while others at 90° (dubbed type 2). Statistical analysis (using Minitab® software) has been applied to determine the statistical significance (modulus at confidence interval varying from 5% to 10%) of the effect of strain rate on composite material response and strength. Both type 1 and type 2 composite laminates were tested at several levels of flexural strain rates varying from 1.8*10−5 s−1 to 7.8*10−3 s−1. For type 1 and type 2 laminates, the flexural fracture stress values were found to increase around 4.5% and 8.6%, respectively, for the studied range of strain rates. It was also found that the flexural modulus of elasticity increased for both 0° and 90° increase in order of 5% and 10%, respectively, for type 1 and type 2 laminates over the strain rate range. This was evidenced by the increase in the variance of the experimentally collected flexural strength values with increasing operating strain rate.","PeriodicalId":146276,"journal":{"name":"Volume 3: Advanced Materials: Design, Processing, Characterization and Applications; Advances in Aerospace Technology","volume":"49 12","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114049957","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}