Advanced Manufacturing: Polymer & Composites Science最新文献

{"title":"Effects of defects on laminate quality and mechanical performance in thermoplastic Automated Fiber Placement-based process chains","authors":"T. Zenker, F. Bruckner, K. Drechsler","doi":"10.1080/20550340.2019.1703334","DOIUrl":"https://doi.org/10.1080/20550340.2019.1703334","url":null,"abstract":"Abstract Automated Fiber Placement of thermoplastic unidirectional tape materials offers several advantages over conventional organosheets, such as enhanced part performance through tailored fiber architecture, and economic and ecological benefits due to scrap reduction. Because material is cut perpendicular to the feeding direction in state-of-the-art machine technology, triangular gaps and overlaps occur when geometrically complex layups are fabricated. Their effect on part properties is unknown for thermoplastic materials. This study investigates the influence of various defect configurations on laminate quality and mechanical performance for different consolidation processes. Analysis of microsections prepared from post-consolidation specimens shows out-of-plane undulations in defect areas. The undulation extent is quantified by angle and deflection. Tensile and compressive testing is performed. Gaps reduce ultimate tensile and compressive strength significantly for variothermal press and autoclave consolidation. Digital-image-correlation-based strain measurement during tensile testing shows strain concentration in the defect area for these specimens. Specimens consolidated in an isothermal stamp forming process show no comparable stress concentration, as well as no reduced ultimate strength. Specimens containing overlaps generally show a better performance in terms of ultimate strength compared to those containing gaps. Even though no full factorial design of experiments was used, the results obtained from this study can be used as a baseline for sector-boundary design strategies. The definition of defect-specific knock-down factors would be a next step towards the solid engineering of thermoplastic Automated Fiber Placement parts.","PeriodicalId":7243,"journal":{"name":"Advanced Manufacturing: Polymer & Composites Science","volume":"17 1","pages":"184 - 205"},"PeriodicalIF":0.0,"publicationDate":"2019-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91008871","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 reference specimen for compaction tests of fiber reinforcements","authors":"D. May, Florian Kühn, M. Etchells, E. Fauster, A. Endruweit, Cristián Delpiano Lira","doi":"10.1080/20550340.2019.1701826","DOIUrl":"https://doi.org/10.1080/20550340.2019.1701826","url":null,"abstract":"Abstract Compaction behavior of textiles has a major influence on the outcome of various manufacturing processes for fiber reinforced polymer composites. Nevertheless, no standard exists up to date which specifies test methods or test rigs. A recent international benchmark revealed high variation associated with the result data. This work is a very first step toward a reference specimen, allowing for an isolated view on variations attributed to the test rig mechanics. A specimen design is proposed, intended to show compaction characteristics similar to technical textiles in terms of transverse compaction pressure and corresponding displacement. The reference specimen was tested in a round-robin study comprising test rigs at four different European research institutions. While reproducibility of the compaction behavior on each of the test rigs was high, clear variations between the results gained with different test rigs were observed. Graphical Abstract","PeriodicalId":7243,"journal":{"name":"Advanced Manufacturing: Polymer & Composites Science","volume":"4 1","pages":"230 - 233"},"PeriodicalIF":0.0,"publicationDate":"2019-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88136719","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":"Heat transfer analysis of automated fiber placement of thermoplastic composites using a hot gas torch","authors":"O. A. Tafreshi, S. Hoa, F. Shadmehri, D. Hoang, D. Rosca","doi":"10.1080/20550340.2019.1686820","DOIUrl":"https://doi.org/10.1080/20550340.2019.1686820","url":null,"abstract":"Abstract With more and more use of composites in engineering applications, the need for automated composites manufacturing is evident. The use of automated fiber placement (AFP) machine for the manufacturing of thermoplastic composites is under rapid development. In this technique, a moving heat source (hot gas torch, laser, or heat lamp) is melting the thermoplastic composite tape and consolidation occurs in situ. Due to the rapid heating and cooling of the material, there are many issues to be addressed. First is the development of the temperature distribution in different directions which gives rise to temperature gradients. Second is the quality of the bond between different layers, and third is the rate of material deposition to satisfy industrial demand. This paper addresses the first issue. The temperature distribution affects the variation in crystallinity, and residual stresses throughout the structure as it is being built. The result is the distortion of the composite laminate even during the process. In order to address this problem, first the temperature distribution due to a moving heat source needs to be determined. From the temperature distribution, the development and distribution of crystallinity, residual stresses and deformation of the structure can then be determined. As the first phase of the work, this paper investigates the temperature distribution due to a moving heat source for thermoplastic composites, without considering the material deposition. A finite difference (FD) code based on energy balance approach is developed to predict the temperature distribution during the process. Unidirectional composite strips are manufactured using AFP and fast-response K-type thermocouples (response time of 0.08 s, as compared to normal thermocouples with response time of 0.5 s) are used to determine the thermal profiles in various locations through the thickness of the composite laminate subjected to a moving heat source. It is shown that temperature variations measured experimentally during the heating pass, using thermocouples embedded into the composite substrate, underneath layers of the composite material, are consistent with the generated thermal profiles from the numerical model. The temperature distribution, in both the direction of the tape and through-thickness direction can be predicted numerically.","PeriodicalId":7243,"journal":{"name":"Advanced Manufacturing: Polymer & Composites Science","volume":"44 1","pages":"206 - 223"},"PeriodicalIF":0.0,"publicationDate":"2019-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74145818","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":"Co-consolidation of CF/PEEK tape-preforms and CF/PEEK organo sheets to manufacture reinforcements in stamp-forming process","authors":"J. Weber, J. Schlimbach","doi":"10.1080/20550340.2019.1673961","DOIUrl":"https://doi.org/10.1080/20550340.2019.1673961","url":null,"abstract":"Abstract Co-consolidation is considered one effective joining method to allow novel types of integral structures to be manufactured. In this study, carbon fiber reinforced Polyether-Ether-Ketone partially consolidated tape preforms were co-consolidated with carbon fiber reinforced Polyether-Ether-Ketone organo sheets in stamp-forming process. Interlaminar bond quality of both joining partners is validated in double cantilever beam test. Results exhibit average interlaminar fracture toughness of 2.54 kJ/m2 for stamp-forming specimen, which exceeds interlaminar fracture toughness of reference samples manufactured in autoclave being 1.79 kJ/m2. Further examinations on specimen morphology and mechanical properties indicate distinct assignments to process characteristic cooling rates, which coincides with studies from literature. Accordingly, high cooling rates—as evident in stamp-forming process—are allocated to high toughness, low crystallinity and low bending modulus, causing high interlaminar fracture toughness. Investigations on laminate quality reveal maximum void content of 1.58%. Graphical Abstract","PeriodicalId":7243,"journal":{"name":"Advanced Manufacturing: Polymer & Composites Science","volume":"18 1","pages":"172 - 183"},"PeriodicalIF":0.0,"publicationDate":"2019-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73214178","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":"Generation of feasible gripper trajectories in automated composite draping by means of optimization","authors":"C. Krogh, J. Sherwood, J. Jakobsen","doi":"10.1080/20550340.2019.1699691","DOIUrl":"https://doi.org/10.1080/20550340.2019.1699691","url":null,"abstract":"Abstract Prepreg composites find great applicability in e.g. the automotive and aerospace industries. A major challenge with this class of material systems is the accurate placement of a fabric that can be very tacky and hence sticks to the mold surface. In this study, automatic draping of entire plies of woven prepregs is considered. A robot end effector with a grid of actuated grippers is under development and it has the ability to position the plies onto double-curved mold surfaces of low curvature. The key issue is how the grippers of the end effector should move to achieve successful drapings of the plies that meet the quality requirements of the industry. In this study, an approximate ply model based on cables with bending stiffness is applied in an optimization framework where the gripper movements constitute the design variables. The optimization framework has taken inspiration from manual layup procedures. The numerical draping results indicate the usefulness of the cable model used in connection with the optimization framework. The next step is to implement the generated gripper trajectories on the physical robot system. Graphical abstract","PeriodicalId":7243,"journal":{"name":"Advanced Manufacturing: Polymer & Composites Science","volume":"6 1","pages":"234 - 249"},"PeriodicalIF":0.0,"publicationDate":"2019-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88836009","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":"Delivering interlaminar reinforcement in composites through electrospun nanofibres","authors":"T. Pozegic, S. King, M. Fotouhi, V. Stolojan, S. Silva, I. Hamerton","doi":"10.1080/20550340.2019.1665226","DOIUrl":"https://doi.org/10.1080/20550340.2019.1665226","url":null,"abstract":"Abstract Electrospun nonwoven veils comprising thermoplastic fibres (average diameter 400–600 nm) based on polysulfone (PSU), polyamide (PA-6,6), and polyetherimide (PEI) have been fabricated and used as interlaminar reinforcements in carbon fibre composites containing a commercial epoxy resin (8552/IM7). Samples were tested for their interlaminar properties and improvements were observed in the initial mode I interlaminar toughness of 30% (PA-6,6), 36% (PEI), and 44% (PSU), while improvements of 7% (PSU) and 8% (PEI) were observed in the propagation of the mode I interlaminar toughness. A reduction of 11% was observed for the propagation of the mode I interlaminar toughness for PA-6,6. Post-testing analysis of the cross-section and the fracture surface revealed that the crack front avoids the reinforcement significantly for PA-6,6. For mode II, however, this failure mechanism leads to improvements of 30% in interlaminar toughness for the PA-6,6, whereas the other reinforcements display negligible (PEI) and 31% reduction (PSU) interlaminar toughness. Graphical Abstract","PeriodicalId":7243,"journal":{"name":"Advanced Manufacturing: Polymer & Composites Science","volume":"55 1","pages":"155 - 171"},"PeriodicalIF":0.0,"publicationDate":"2019-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80306428","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 recyclable epoxy for composite wind turbine blades","authors":"Ming-Sung Wu, B. Jin, Xin Li, S. Nutt","doi":"10.1080/20550340.2019.1639967","DOIUrl":"https://doi.org/10.1080/20550340.2019.1639967","url":null,"abstract":"Abstract Disposal of wind turbine blades, which are generally non-biodegradable and non-recyclable products comprised largely of fiber-reinforced thermoset polymers (FRPs), pose environmental problems when components reach end-of-service-life. Because the global wind turbine market shows steady year-over-year growth, the need for a recycling solution for wind blade FRPs is urgent and growing rapidly. In the present study, recyclable resins, formulated using proprietary epoxy curing agents (Cleavamine®, Adesso), were charactered and analyzed for processability and recyclability. Protocols for vacuum infusion processing were developed for these recyclable resins. Secondly, laminates of glass fibers and the above epoxy matrices were first produced then recycled, and the properties of recovered fibers were evaluated. Matrix and laminate properties were compared to a benchmark commercial epoxy presently used in commercial wind blades. Results showed that vacuum infusion with the recyclable resins yielded laminates with low void contents and properties comparable to non-recyclable commercial epoxies, and the recovered glass fibers retained surface quality comparable to virgin fibers. Furthermore, results also showed that the recovered matrix residue can be re-used in second-life applications, effectively completing the closed-loop recycling method in this study. Graphical Abstract","PeriodicalId":7243,"journal":{"name":"Advanced Manufacturing: Polymer & Composites Science","volume":"12 1","pages":"114 - 127"},"PeriodicalIF":0.0,"publicationDate":"2019-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78294528","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":"The use of discontinuous PEEK/carbon fiber thermoplastic moulding compounds for thick-section componentry","authors":"S. Erland, L. Savage","doi":"10.1080/20550340.2019.1639968","DOIUrl":"https://doi.org/10.1080/20550340.2019.1639968","url":null,"abstract":"Abstract The hot-pressing of discontinuous fiber moulding compounds (DFMCs) is an established way of forming geometrically complex components, however, it is not a simple process. Rapid and irreversible cure cycles hinder the use of thermoset resins, and thermoplastic resins offer inferior mechanical performance. The recent availability of DFMCs utilising a Polyether Ether Ketone (PEEK) matrix offer an alternative, combining the usability of thermoplastics with significantly enhanced mechanical properties. A novel manufacturing approach is proposed and investigated, in which virgin material is consolidated into multiple ‘pre-charges’ prior to pressing the final component, combating the limitations of DFMCs; loft, voidage and fiber orientation. Short beam shear tests were employed to assess the mechanical implications of laminating DFMCs, demonstrating minimal differences to a standard sample. Three-point bend tests assessed rudimentary orientation of fiber bundles, showing significantly improved mechanical performance at the cost of toughness. A novel method to determine the interlaminar shear modulus is also presented and successfully validated. Graphical abstract","PeriodicalId":7243,"journal":{"name":"Advanced Manufacturing: Polymer & Composites Science","volume":"39 1","pages":"100 - 113"},"PeriodicalIF":0.0,"publicationDate":"2019-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77995162","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":"Influence of test fluids on the permeability of epoxy powder bindered non-crimp fabrics","authors":"Maximilian Tonejc, Catharina Ebner, E. Fauster, R. Schledjewski","doi":"10.1080/20550340.2019.1647371","DOIUrl":"https://doi.org/10.1080/20550340.2019.1647371","url":null,"abstract":"Abstract Binder applications have found their place in liquid composite molding processes, as they simplify preprocessing steps such as preforming and subsequent handling. Moreover, binders can modify mechanical behavior of finished fiber reinforced plastic parts. Besides the obvious potentials, topics such as the impregnation behavior become more complicated due to binders. The present paper addresses the issue of estimating permeability values of epoxy powder bindered non-crimp fabrics, after considering different test fluids and their behavior under standard laboratory conditions as well as manufacturing-oriented conditions. Test fluid properties, especially surface energy as well as viscosity development with respect to temperature were provided, thereby highlighting a more complete picture of the flow situation during resin transfer molding processes. In contrary to former scientific studies, the influence of test fluids seems to have more influence when investigating Bindered Preforms.","PeriodicalId":7243,"journal":{"name":"Advanced Manufacturing: Polymer & Composites Science","volume":"14 1","pages":"128 - 139"},"PeriodicalIF":0.0,"publicationDate":"2019-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78214144","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 controlled recipient evacuation process to form composite profiles from flat multi-angle prepreg stacks – infrastructure and C-profile verification","authors":"E. Kappel, M. Albrecht","doi":"10.1080/20550340.2019.1660455","DOIUrl":"https://doi.org/10.1080/20550340.2019.1660455","url":null,"abstract":"Abstract Single-diaphragm forming is a cost saving alternative to labor-intensive ply-by-ply layup. This paper reports on forming of flat uncured multi-angle prepreg stacks into C shape. The main focus is on the forming-process profile , which has attracted little attention in previous studies on the topic. Hexcel’s M21E/IMA prepreg is examined within the study to analyze the particular effect of the prepreg’s interleaf layers on the forming process and vice versa. Specimens with different multi-angle stackings were formed at 40, 60 and 80 °C, on male tools with 4, 6 and 8 mm radii. It is shown that the composed infrastructure setup allows for a precise control of the recipient pressure profile. The forming status is monitored based on a resistance-measurement-based approach, whose application suggests a two-phase forming process characteristic. Recipient pressure levels of 60 and 510 mbar below ambient pressure were identified as practical for gentle forming. It could be shown that interleaf layers of M21E/IMA specimens are not harmed considerably by the forming procedure. Overall, the proposed forming process led to prepreg preforms of adequate quality, suitable for series production. Graphical Abstract","PeriodicalId":7243,"journal":{"name":"Advanced Manufacturing: Polymer & Composites Science","volume":"55 1","pages":"140 - 154"},"PeriodicalIF":0.0,"publicationDate":"2019-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80415351","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}