American Society for Composites 2018最新文献

{"title":"A Benchmark Example for Delamination Propagation Predictions Based on the Single Leg Bending Specimen Under Quasi-static and Fatigue Loading","authors":"R. Krueger, L. Deobald, H. Gu","doi":"10.12783/ASC33/26004","DOIUrl":"https://doi.org/10.12783/ASC33/26004","url":null,"abstract":"Benchmark examples based on Single Leg Bending (SLB) specimens with equal and unequal bending arm thicknesses were used to assess the performance of delamination prediction capabilities in finite element codes. First, the development of the quasi-static benchmark cases using the Virtual Crack Closure Technique (VCCT) is discussed in detail. Second, based on the quasi-static benchmark results, additional benchmark cases to assess delamination propagation under fatigue loading are created. Third, the application is demonstrated for the commercial finite element code Abaqus Standard 2018. The benchmark cases are compared to results obtained from VCCTbased, automated quasi-static propagation analysis. A comparison with results from automated fatigue propagation analysis was not performed at this point since the current version of Abaqus does not include this capability under variable mixed-mode conditions. In general, good agreement between the results obtained from the quasistatic propagation analysis and the benchmark results were achieved. Overall, the benchmarking procedure proved valuable for analysis verification.","PeriodicalId":337735,"journal":{"name":"American Society for Composites 2018","volume":"33 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126094358","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":"Discrete Damage Modeling of Matrix Dominated Failure Including Random Spatial Variation of Strength","authors":"K. Hoos, E. Iarve","doi":"10.12783/ASC33/26054","DOIUrl":"https://doi.org/10.12783/ASC33/26054","url":null,"abstract":"Discrete Damage Modeling (DDM) was applied to strength prediction of three types of composite tape specimens exhibiting rather brittle behavior. These were transverse tensile coupons, three-point bend 90° coupons and NASA LaRC Clamped Tapered Beam sub-element. The performed strength predictions are sensitive to the value of the transverse tensile strength Yt. Deterministic strength predictions required different values of Yt for realistic prediction of strength for the three specimen categories. Weibull scaled seeding of transverse tensile strength was introduced to address this problem. Cohesive Zone Method (CZM) in the field of random initiation strength distribution was examined and revealed that a finite seed length is required in order the reproduce brittle behavior. A 0.4mm seed length window was applied and resulted in realistic predictions of strength in all three specimens based on the Yt=64MPa measured on standard ASTM 90° coupons and Weibull modulus of α=13. INTRODUCTION Laminated composite materials are used in a variety of aerospace, automotive, and sports equipment applications. In designing these parts, coupon tests are performed to determine the material properties to be used in the design. However, manufacturing and material variation cause significant strength variations within a single part in all three material directions. Significant amount of work was devoted to measurement and characterization of variation of basic stiffness and strength properties of tape composites, and in-situ transverse tensile strength in particular. The subject literature is very extensive and the reader is referred to recent experimental work [1] including ______________ 1 Institute for Predictive Performance Methodologies, University of Texas Arlington Research Institute, 7300 Jack Newell Blvd. S., Fort Worth, TX, 76118 2 Department of Mechanical and Aerospace Engineering, University of Texas at Arlington, Woolf Hall, Room 211, Box 19023, Arlington, TX 76019 references. While the mechanism and interlay of strength controlled initiation and fracture mechanics controlled propagation as a function of ply thickness are well understood, it is pointed out that additional brittle strength scaling concepts are required to explain the entire spectrum of results. Understanding the implications of input property variation and scaling is also critical to application of progressive damage analysis (PDA) to design and certification of composite structures. Thus recently performed simulations of failure initiation and propagation in Clamped Tapered Beam (CTB) specimens [2] showed good agreement with experimental data for ply level transverse strength parameter obtained by using 3 point bend (3PB) test method [3] whereas the results obtained by using an almost two times lower value resulting from tensile testing of 90° coupons [4] resulted in 30% underprediction of the peak load. The goal of the present work is to introduce spatial scatter of transverse strength pa","PeriodicalId":337735,"journal":{"name":"American Society for Composites 2018","volume":"2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125289192","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":"Experimental Characterization of Mode I and Mode II Peridynamic Critical Stretch Parameter","authors":"F. Baber, V. Ranatunga, I. Guven","doi":"10.12783/asc33/25979","DOIUrl":"https://doi.org/10.12783/asc33/25979","url":null,"abstract":"The focus of this study is to determine the critical stretch parameters for laminated composites when using peridynamic approach for modeling interlaminar delaminations in idealized modes I and II with and without z-pin reinforcements. The doublecantilever beam test and the end-notch flexure test were used to evaluate the normal (Mode I) and shear (Mode II) bond critical stretch in the absence of z-pins. Subsequently, the interlaminar delaminations with z-pins were simulated in order to evaluate the corresponding critical stretch.","PeriodicalId":337735,"journal":{"name":"American Society for Composites 2018","volume":"59 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124010896","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":"An Engineering Approach to Analyze Damage Initiation Modes in Tapered Composite Structures","authors":"P. Rao, U. Palliyaguru, M. Gurvich, W. Seneviratne","doi":"10.12783/ASC33/26098","DOIUrl":"https://doi.org/10.12783/ASC33/26098","url":null,"abstract":"In this work an engineering approach is demonstrated for analyzing damage initiation modes in tapered composite structures. The analysis methodology includes simulation of the non-linear static response of tapered composite structures under static tension loads to predict the location of interfacial delamination initiation. Furthermore, the developed methodology provides a strength-based criterion to assess whether damage initiation will occur in the inter-laminar delamination or intra-laminar matrix cracking mode. Based on the results of the analysis, a tapered composite structure is fabricated and tested under displacement-controlled quasi-static tension loading. The damage initiation location captured experimentally is compared with the analysis towards achieving preliminary qualitative validation. The linear stiffness of the tapered composite structure is predicted within 15% of the experimental average thereby achieving preliminary quantitative validation.","PeriodicalId":337735,"journal":{"name":"American Society for Composites 2018","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128941680","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":"An Investigation of Inner Flange Buckling in Furlable Composite Booms","authors":"K. Cox, Kamron A. Medina","doi":"10.12783/ASC33/26162","DOIUrl":"https://doi.org/10.12783/ASC33/26162","url":null,"abstract":"The triangular rollable and collapsible (TRAC) boom is an attractive architecture for deployable spacecraft structures due to its minimal flattened height-to-deployed stiffness ratio. A challenge for TRAC booms however is the development of a buckling mode that occurs (on the inner flange) when furling the boom around a hub for stowage. In this research, the buckling mode was found to be sensitive to boom flange length and the composite flexural stiffnesses dictated by the laminate materials, fiber orientations and ply stacking sequence. Finite element studies were performed to investigate the influence of flange arc length and composite layup on critical stresses and strains prompted by the buckled wave. Longer flange lengths resulted in higher strains but could be offset through modifications to the laminate architecture allowing for larger booms to be packaged without increasing the minimum stowage (hub) diameter. The analysis model was validated through experimental furling tests and successful correlation between the simulation strains and experimental strain gages.","PeriodicalId":337735,"journal":{"name":"American Society for Composites 2018","volume":"85 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127450843","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":"Multifunctional MENs Doped Adhesives for Bond Quality Evaluation","authors":"Ping Wang, D. Gil, M. Pajon, B. Hernandez, Juliette Dubon, B. Boesl, S. Khizroev, B. Arkook, D. McDaniel","doi":"10.12783/ASC33/26106","DOIUrl":"https://doi.org/10.12783/ASC33/26106","url":null,"abstract":"Adhesive bonding for composite structures offers multiple advantages over traditional fasteners such as reducing the weight, creating a more uniformly distributed stress state in the joint, and elimination of stress concentration factors due to joining. However, the strength of adhesive bonds can be reduced due to environmental exposure, contamination, mechanical damage and fatigue and assurances of long-term durability and bond strength are not available. Before adhesive bonding of composites can be used on primary structures, a method for guaranteeing the bonds strength must be developed. Due to magneto-electric principles, magneto-electric nanoparticles (MENs) can be used to detect minute changes of electric fields at the molecular level through detectable changes of the nanoparticles’ magnetization. As a result, when integrated into epoxy based adhesives, MENs are capable of detecting chemical or mechanical induced material imperfections at the molecular level. Current efforts are focused on developing a field tool that can be used to obtain magnetic signatures from doped adhesives similar to those obtained via laboratory scale equipment (vibrating sample magnetometer). To achieve similar sensitivities, FIU is investigating the use of a B-H looper system. In this approach, the MENs material is probed with a specifically designed setup that includes small electric coils wrapped around the sample. The coils are arranged into a noisecancellation configuration to measure the magnetic susceptibility of the sample under various conditions with a lock-in amplifier. With the goal to identify signature response characteristics of specific environmental and mechanical effects, various epoxy based adhesive samples were doped with 30 nm diameter MENs. Differences in magnetic signatures were observed between environmentally aged samples and baseline samples, demonstrating the viability of the B-H looper system as a bond inspection tool.","PeriodicalId":337735,"journal":{"name":"American Society for Composites 2018","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129201584","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":"Multi-Scale Analysis of Joints in Hybrid Metal/Composite Structures in ESI Virtual Performance Solution (VPS)","authors":"Alexandre S. Dumon, S. Mueller, P. Luca, A. Trameçon","doi":"10.12783/ASC33/25982","DOIUrl":"https://doi.org/10.12783/ASC33/25982","url":null,"abstract":"The lack of maturity of crash simulation of structures made of hybrid materials is a key issue for lightweight engineering in automotive industry. Tailoring local behavior and mixing materials while accounting for this mix and joining problematics in the simulation methodology are required to optimize weight and costs, without the need of a real prototype. Current lightweight vehicle programs use local strengthening of structural body components through hot or warm formed high strength steels joined with spot-welds. New metals or composites parts with new joining techniques are progressively introduced for the next stage of weight saving. Local reinforcement by thermo-plastic composites is also considered to offset costs trade-offs.","PeriodicalId":337735,"journal":{"name":"American Society for Composites 2018","volume":"25 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133762144","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":"Cycloaliphatic Epoxy -Silica Nanocomposite Provided from Perhydropolysilazane","authors":"R. Saito, T. Sakaguchi, Akio Takasugi","doi":"10.12783/asc33/26083","DOIUrl":"https://doi.org/10.12783/asc33/26083","url":null,"abstract":"","PeriodicalId":337735,"journal":{"name":"American Society for Composites 2018","volume":"101 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133634610","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":"A Method for Rapid Determination of Fiber Orientation in Reinforced Composites at Lab and Component Scale","authors":"M. Kant, D. Penumadu","doi":"10.12783/asc33/25984","DOIUrl":"https://doi.org/10.12783/asc33/25984","url":null,"abstract":"","PeriodicalId":337735,"journal":{"name":"American Society for Composites 2018","volume":"31 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130329206","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":"Optimal Design of Composite Shells with Multiple Cutouts Based on POD and Machine Learning Methods","authors":"K. Tian, Shiyao Lin, Jiaxin Zhang, A. Waas","doi":"10.12783/ASC33/26160","DOIUrl":"https://doi.org/10.12783/ASC33/26160","url":null,"abstract":"Due to the high specific stiffness and strength, composite shells have been widely used in fuel tanks of launch vehicles. The buckling analysis of composite shells with cutouts based on the finite element (FE) method is too time-consuming. From the point-of-view of model size reduction, a novel Proper Orthogonal Decomposition (POD)-based buckling method is proposed in this paper, which can significantly increase the computational efficiency of buckling analysis. In order to improve the efficiency and effectiveness of prediction and optimization of composite shells with multiple cutouts, the POD method is integrated into an optimization framework that uses Gaussian process (GP) machine learning method. First, the training set used for the machine learning training is generated efficiently by means of the POD method. Then, the obtained set is trained and tested based on the Gaussian process method. The inputs are ply angles of the composite shell and the output is the buckling load of the composite shell containing cutouts. In order to maximize the buckling load of the composite shell against cutouts, the Genetic Algorithm is combined with the trained Gaussian process method to search for the optimal ply angles. Finally, an illustrative example is carried out to demonstrate the effectiveness of the proposed prediction and optimization framework.","PeriodicalId":337735,"journal":{"name":"American Society for Composites 2018","volume":"74 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131260703","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}