Development and testing of material extrusion additive manufactured polymer–textile composites

© 2021, The Author(s). The adoption of Additive Manufacturing (AM) has gradually transformed the fashion industry through innovation and technology over the last decade. Novel AM systems and techniques are continuously being developed, leading to the application of AM polymers with textiles and fabrics in the fashion industry. This work investigates the development and testing of polymer–textile composites using polylactic acid (PLA) filaments on synthetic mesh fabrics using direct material extrusion (ME). An aspect of this paper highlights the appropriate combination of printing material, textile substrate, and printer settings to achieve excellent polymer–textile adhesion. Details of the printing process to create polymer–textile composites are described, as are the interfacial strength results of the T-peel tests, and the observed failure modes post-testing. The peel strengths for different ME bonded polymer–textile composites are examined and used to identify the compatibility of materials. This work visualised the potential of direct ME of polymers onto textile fabrics as a material-joining approach for new textile functionalisation, multi-material composite explorations and innovative aesthetic print techniques. This work also adds to the limited knowledge of AM polymer–textile composites, which can provide helpful information for designers and researchers to develop new applications and facilitate future research development in smart embedded and programmable textiles

Development, characterisation and Finite Element modelling of novel waste carpet composites for structural applications

© 2018 Elsevier Ltd Carpets are composite materials and, like many composite materials, waste carpet is both difficult and expensive to recycle because of the complicated, multi-stage processes involved. Consequently, in the United Kingdom, approximately 400,000 tonnes of carpet waste are sent to landfill annually. However, the landfill option is becoming uneconomic due to increasing landfill charges, the reduction in landfill sites and changes in environmental legislation. This dual economic and environmental burden has led to research interest in the processing of waste carpets into useful feedstocks for use in manufacturing. This study describes the experimental characterisation of a novel structural composite material that has been fabricated from waste carpets, and which is intended for use in low grade structural applications such as agricultural fencing. Details of the manufacturing process for the composites are described, as are the results of tensile and three-point bending tests, and the observed failure modes post-testing. In addition, Finite Element (FE) analysis was used to simulate the structural behaviour of fencing posts and rails manufactured from the carpet-based composite, and these results are compared with commercially available timber and PVC equivalent designs. Finally, structural analysis and design optimisation of the composite fencing was undertaken and this is used to demonstrate that from a mechanical property standpoint, the novel waste carpet structural composite may offer potential as an alternative to the timber and PVC materials typically used in such applications. Therefore, this study has demonstrated a practical approach for recycling carpet waste, which could lead to a substantial reduction in the volume of carpet waste discarded to landfill and subsequently yield both economic and environmental benefits.The authors wish to record their appreciation to the Centre for Global Eco-Innovation and the Engineering Department of Lancaster University for supporting their research. The Centre for Global Eco-Innovation is part-financed by the European Regional Development Fund (Grant No. X02646PR). In addition, they wish to thank Richard Wilbraham and Mohammed Milad for their assistance with the Scanning Electron Microscopy (SEM) analysis and Digital Image Correlation (DIC) operation, respectively

Experimental characterisation of the moment-rotation behaviour of beam-beam connections using compressed wood connectors

© 2021 The Authors. The widespread use of energy-intensive metallic connectors and synthetic adhesives in modern timber construction has negative implications for the end-of-life disposal or re-use of the structural timber components. Therefore, it is favourable to substitute metallic connectors and synthetic adhesives with bio-based alternatives such as wood-based connectors. Recent studies have shown that densified or compressed wood (CW) with superior mechanical properties could be suitable for the manufacture of wood-based connectors in the form of CW dowels and CW plates. This study experimentally examines the moment-rotation behaviour of semi-rigid type timber-CW beam-beam connections under pure bending. The study also assesses the suitability of current design rules to predict the moment capacity of timber-CW connections. The comparative study has shown that the moment capacity of the timber-CW connection can be conservatively predicted from the characteristic load-carrying capacity of the connections calculated using the EC 5 strength equations.European Regional Development Fund (ERDF) via Interreg North-West Europe grant 348 “Towards Adhesive Free Timber Buildings - AFTB”

Experimental investigation of the moment-rotation behaviour of beam-column connections produced using compressed wood connectors

Copyright © 2022 The Authors. The use of timber in construction in medium–high rise construction has increased in recent years largely due to the significant innovation in engineered wood products and connection technology coupled with a desire to utilise more environmentally sustainable construction materials. While engineered wood products offer a low-carbon solution to the construction industry, the widespread use of adhesive and metallic fasteners often limits the recyclability of the structural components at the end of life of the structure and it may be beneficial to reduce this where possible. To establish the possibility of an all-wood connection solution, this preliminary study examines a series of beam-column connections designs to evaluate the relative performance of the different designs, which are connected with modified or compressed wood (CW) connectors. The connection designs are formed between glued-laminated beam and column members in the first instance and later examined when connecting dowel-laminated timber (DLT) members. The results show that significant moment capacity and rotational stiffness can be achieved for connections solely connected using CW fasteners. Furthermore, the all-wood solution utilising CW fasteners to connect DLT members has also demonstrated significant moment capacity and rotational stiffness capacity without the use of adhesive and metallic components.Interreg North-West Europe (NWE) funded by the European Regional Development Fund (ERDF) for supporting their project Towards Adhesive Free Timber Buildings (AFTB) - Grant ID: NWE_348

Review of state of the art of dowel laminated timber members and densified wood materials as sustainable engineered wood products for construction and building applications

Copyright © 2019 The Authors. Engineered Wood Products (EWPs) are increasingly being used as construction and building materials. However, the predominant use of petroleum-based adhesives in EWPs contributes to the release of toxic gases (e.g. Volatile Organic Compounds (VOCs) and formaldehyde) which are harmful to the environment. Also, the use of adhesives in EWPs affects their end-of-life disposal, reusability and recyclability. This paper focusses on dowel laminated timber members and densified wood materials, which are adhesive free and sustainable alternatives to commonly used EWPs (e.g. glulam and CLT). The improved mechanical properties and tight fitting due to spring-back of densified wood support their use as sustainable alternatives to hardwood fasteners to overcome their disadvantages such as loss of stiffness over time and dimensional instability. This approach would also contribute to the uptake of dowel laminated timber members and densified wood materials for more diverse and advanced structural applications and subsequently yield both environmental and economic benefits.Interreg North-West Europe (NWE) funded by the European Regional Development Fund (ERDF) supporting the project (Towards Adhesive Free Timber Buildings (AFTB) - 348)

31st Annual Meeting and Associated Programs of the Society for Immunotherapy of Cancer (SITC 2016) : part two

Background The immunological escape of tumors represents one of the main ob- stacles to the treatment of malignancies. The blockade of PD-1 or CTLA-4 receptors represented a milestone in the history of immunotherapy. However, immune checkpoint inhibitors seem to be effective in specific cohorts of patients. It has been proposed that their efficacy relies on the presence of an immunological response. Thus, we hypothesized that disruption of the PD-L1/PD-1 axis would synergize with our oncolytic vaccine platform PeptiCRAd. Methods We used murine B16OVA in vivo tumor models and flow cytometry analysis to investigate the immunological background. Results First, we found that high-burden B16OVA tumors were refractory to combination immunotherapy. However, with a more aggressive schedule, tumors with a lower burden were more susceptible to the combination of PeptiCRAd and PD-L1 blockade. The therapy signifi- cantly increased the median survival of mice (Fig. 7). Interestingly, the reduced growth of contralaterally injected B16F10 cells sug- gested the presence of a long lasting immunological memory also against non-targeted antigens. Concerning the functional state of tumor infiltrating lymphocytes (TILs), we found that all the immune therapies would enhance the percentage of activated (PD-1pos TIM- 3neg) T lymphocytes and reduce the amount of exhausted (PD-1pos TIM-3pos) cells compared to placebo. As expected, we found that PeptiCRAd monotherapy could increase the number of antigen spe- cific CD8+ T cells compared to other treatments. However, only the combination with PD-L1 blockade could significantly increase the ra- tio between activated and exhausted pentamer positive cells (p= 0.0058), suggesting that by disrupting the PD-1/PD-L1 axis we could decrease the amount of dysfunctional antigen specific T cells. We ob- served that the anatomical location deeply influenced the state of CD4+ and CD8+ T lymphocytes. In fact, TIM-3 expression was in- creased by 2 fold on TILs compared to splenic and lymphoid T cells. In the CD8+ compartment, the expression of PD-1 on the surface seemed to be restricted to the tumor micro-environment, while CD4 + T cells had a high expression of PD-1 also in lymphoid organs. Interestingly, we found that the levels of PD-1 were significantly higher on CD8+ T cells than on CD4+ T cells into the tumor micro- environment (p < 0.0001). Conclusions In conclusion, we demonstrated that the efficacy of immune check- point inhibitors might be strongly enhanced by their combination with cancer vaccines. PeptiCRAd was able to increase the number of antigen-specific T cells and PD-L1 blockade prevented their exhaus- tion, resulting in long-lasting immunological memory and increased median survival

Experimental investigation on the effect of accelerated ageing conditions on the pull-out capacity of compressed wood and hardwood dowel type fasteners

Interreg North-West Europe grant 34

Timber screw connection: Study of the strain along the interface using optical measurement techniques and simulations

The results presented in this study are part of the research project “WoodC.A.R.” (Project No. 861.421).Copyright © 2022 The Authors. In various engineering applications, self-tapping screws are used to connect timber members. To describe their load-deformation relationship, a better understanding of the strain along the mechanical interface (i.e., timber-screw interface) is required. With a focus on the axial loading of self-tapping screws, only a few studies have dealt with the determination of the strain based on optical measurement techniques. Therefore, in the present study, the strain distribution at the timber-screw interface was monitored during pull-out tests using an optical measurement technique, called electronic speckle pattern interferometry (ESPI). Strains obtained from the ESPI measurements were compared with the results obtained from structural simulations conducted with finite element modelling (FEM). Three different types of solid spruce wood (Picea abies (L.) Karst.) specimens with different grain orientations connected with self-tapping screws (thread length lg = 130 mm, outer thread diameter d = 12 mm) were tested in withdrawal. There was a good agreement between the ESPI and FEM results, confirming that ESPI was a suitable measurement technique. The study also provided insights and results regarding the region of strain concentrations across the length of self-tapping screws.Austrian Research Promotion Agency (FFG), Styrian Business Promotion Agency (SFG), Standortagentur Tirol, and the companies ACstyria Autocluster GmbH, Collano AG, DOKA GmbH, DYNAmore Gesellschaft für FEM Ingenieurdienstleistungen mbH, EJOT AUSTRIA GmbH & Co KG, FHP – Kooperationsplattform Forst Holz Papier, Holzcluster Steiermark GmbH, DI Gottfried Steiner, Lean Management Consulting GmbH, MAGNA STEYR Fahrzeugtechnik AG & Co KG, MAN Truck & Bus SE, Mattro GmbH, Volkswagen AG, and Weitzer Parkett GmbH & Co K

Experimental investigations on adhesive free laminated oak timber beams and timber-to-timber joints assembled using thermo-mechanically compressed wood dowels

© 2019 Elsevier Ltd This paper presents an experimental investigation on a novel adhesive free engineered Wood Products (AFEWPs) as an alternative to the conventional glued EWPs which have a high degree of petrochemicals. The research outcomes demonstrate the feasibility of using compressed wood dowels (CWD) as a joint element, to connect timber laminates and members as well as to substitute for adhesives and metallic fasteners. The paper describes the production of thermo-mechanically compressed wood dowels as well as the manufacturing of the dowelled timber specimens. The strength and stiffness properties of CWD are characterized based on three-point bending tests and compared to the values obtained from uncompressed wood specimens. After that, the paper discusses the relative mechanical performances of three-layer dowelled oak beams subjected to four-point bending, in comparison to their conventional glued counterparts. Finally, the paper shows results obtained from double shear push-out tests under both monotonic and cyclic loadings, using two wood species, namely spruce and oak. The obtained results show clearly the potential of thermo-mechanically compressed wood dowel, as a joint fastener, for load bearing capacity