Experimental and finite element analysis of a double strap joint between steel plates and normal modulus CFRP

Strengthening of steel structures using externally-bonded carbon fibre reinforced polymers ‘CFRP’ is a rapidly developing technique. This paper describes the behaviour of axially loaded flat steel plates strengthened using carbon fibre reinforced polymer sheets. Two steel plates were joined together with adhesive and followed by the application of carbon fibre sheet double strap joint with different bond lengths. The behaviour of the specimens was further investigated by using nonlinear finite element analysis to predict the failure modes and load capacity. In this study, bond failure is the dominant failure mode for normal modulus (240 GPa) CFRP bonding which closely matched the results of finite elements. The predicted ultimate loads from the FE analysis are found to be in good agreement with experimental values.

Double strap joint tests to determine the bond characteristics between CFRP and steel plates

Advanced composite materials offer remarkable potential in the upgrade of civil engineering structures. The evolution of CFRP (carbon fibre reinforced polymer) technologies and their versatility for applications in civil constructions require comprehensive and reliable codes of practice. Guidelines are available on the rehabilitation and retrofit of concrete structures with advanced composite materials. However, there is a need to develop appropriate design guidelines for CFRP strengthened steel structures. It is important to understand the bond characteristics between CFRP and steel plates. This paper describes a series of double strap shear tests loaded in tension to investigate the bond between CFRP sheets and steel plates. Both normal modulus (240 GPa) and high modulus (640 GPa) CFRPs were used in the test program. Strain gauges were mounted to capture the strain distribution along the CFRP length. Different failure modes were observed for joints with normal modulus CFRP and those with high modulus CFRP. The strain distribution along the CFRP length is similar for the two cases. A shorter effective bond length was obtained for joints with high modulus CFRP whereas larger ultimate load carrying capacity can be achieved for joints with normal modulus CFRP when the bond length is long enough.

Bond–slip models for double strap joints strengthened by CFRP

This paper presents the results of a series of tension tests on CFRP bonded steel plate double strap joints. The main aim of this research is to provide detailed understanding of bond characteristics using experimental and numerical analysis of strengthened double strap joints under tension. A parametric study has been performed by numerical modelling with the variables of CFRP bond lengths, adhesive maximum strain and adhesive layer thicknesses. Finally, bond-slip models are proposed for three different types of adhesives within the range of the parametric study.

Bond characteristics between CFRP and steel plates in double strap joints

This paper describes a series of double strap shear tests loaded in tension to investigate the bond between CFRP sheets and steel plates. Both normal modulus (240 GPa) and high modulus (640 GPa) CFRPs were used in the test program. Strain gauges were mounted to capture the strain distribution along the CFRP length. Different failure modes were observed for joints with normal modulus CFRP and those with high modulus CFRP. The strain distribution along the CFRP length was found to be similar for the two cases. A shorter effective bond length was obtained for joints with high modulus CFRP whereas larger ultimate load carrying capacity can be achieved for joints with normal modulus CFRP when the bond length is long enough. The Hart-Smith Model was modified to predict the effective bond length and ultimate load carrying capacity of joints between the normal modulus CFRP and steel plates. The Multilayer Distribution Model developed by the authors was modified to predict the load carrying capacity of joints between the high modulus CFRP and steel plates. The predicted values agreed well with experimental ones.

Evaluation of shear stress and slip relationship of composite lap joints

Advanced composite materials offer remarkable potential in the strengthening of Civil Engineering structures. This research is targeted to provide in depth knowledge and understanding of bond characteristics of advanced and corrosion resistant material carbon fibre reinforced polymer (CFRP) that has a unique design tailor-ability and cost effective nature. The objective of this research is to investigate and compare the bonding mechanism between CFRP strengthened single and double strap steel joints. Investigations have been made in regards to failure mode, ultimate load and effective bond length for CFRP strengthened double and single strap joints. A series of tensile tests were conducted with different bond lengths for both type of joints. The bond behaviour of these specimens was further investigated by using nonlinear finite element analysis. Finally a bilinear relationship of shear stress-slip has been proposed by using the Finite element model for single and double strap joints.

Preliminary bond-slip model for CFRP sheets bonded to steel plates

Carbon fiber reinforced polymer (CFRP) sheets have established a strong position as an effective method for innovative structural rehabilitation. However, the use of externally bonded CFRP in the repair and rehabilitation of steel structures is a relatively new technique that has the potential to improve the way structures are repaired. An important step toward understanding bond behaviour is to have an estimation of local bond stress versus slip relationship. The current study aims to establish the bond-slip model for CFRP sheets bonded to steel plate. To obtain the shear stress versus slippage relationship, a series of double strap tension type bond tests were conducted. This paper reports on the findings of the experimental studies. The strain and stress distributions measured in the specimens for two different bond lengths. The results show a preliminary bi-linear bond-slip model may be adopted for CFRP sheet bonded with steel plate.

Bond Characteristics of Strengthened and Retrofitted Steel by Smart CFRP Technique

Usage of new smart materials in retrofitting of structures has become popular within last decade. Carbon fiber reinforced polymer (CFRP) has been widely used in retrofitting and strengthening of concrete structures and its usage in metallic structures is still in the developing stage. The variation of mechanical properties of CFRP and the consequent effects on strengthening and retrofitting CFRP systems are yet to be investigated under different loading and environmental conditions. This paper presents the results of CFRP strengthened and retrofitted corroded steel plate double strap joints under tension. An accelerated corrosion cell has been developed to accelerate the corrosion of the steel samples and CFRP strengthened samples. The results show a direct comparison of bond characteristics of CFRP strengthened and retrofitted steel double strap joints.

Strengthening of circular hollow steel tubular sections using high modulus CFRP sheets

This paper describes the behaviour of very high strength (VHS) circular steel tubes strengthened by carbon fibre reinforced polymer (CFRP) and subjected to axial tension. A series of tests were conducted with different bond lengths and number of layers. The distribution of strain through the thickness of CFRP layers and along CFRP bond length was studied. The strain was found to generally decrease along the CFRP bond length far from the joint. The strain through the thickness of the CFRP layers was also found to decrease from bottom to top layer. The effective bond length for high modulus CFRP was established. Finally empirical models were developed to estimate the maximum load for a given CFRP arrangement.

Digital broadcasting : a double edge sword in protecting children from disturbing news content

New technologies have the potential to both expose children to and protect them from television news footage likely to disturb or frighten. The advent of cheap, portable and widely available digital technology has vastly increased the possibility of violent news events being captured and potentially broadcast. This material has the potential to be particularly disturbing and harmful to young children. But on the flipside, available digital technology could be used to build in protection for young viewers especially when it comes to preserving scheduled television programming and guarding against violent content being broadcast during live crosses from known trouble spots. Based on interviews with news directors, parents and a review of published material two recommendations are put forward: 1. Digital television technology should be employed to prevent news events "overtaking" scheduled children's programming and to protect safe harbours placed in the classifications zones to protect children. 2. Broadcasters should regain control of the images that go to air during "live" feeds from obviously volatile situations by building in short delays in G classification zones.

Stress distribution of CFRP strengthened steel hollow sections under tension

Carbon fibre reinforced polymer (CFRP) sheets have many outstanding properties such as high strength, high elastic modulus, light weight and good durability which are made them a suitable alternative for steel in strengthening work. This paper describe the ultimate load carrying capacity of steel hollow sections at effective bond length in terms of its cross sectional area and the stress distribution within bond region for different layers CFRP. It was found that depending on their size and orientation of uni- directional CFRP layers, the ultimate tensile load was different. Along with these tests, non linear finite element analysis was also performed to validate the ultimate load carrying capacity depending on their cross sections. The predicted ultimate loads from FE analysis are found very close to the laboratory test results. The validated model has been used to determine the stress distribution at bond joint for different orientation of CFRP. This research shows the effect of stress distribution and suitable wrapping layer to be used for the strengthening of steel hollow sections in tension.

A Submission to the Joint Standing Committee on Treaties on the Anti-Counterfeiting Trade Agreement 2011 (# ACTA)

“If Hollywood could order intellectual property laws for Christmas, what would they look like? This is pretty close.” David Fewer “While European and American IP maximalists have pushed for TRIPS-Plus provisions in FTAs and bilateral agreements, they are now pushing for TRIPS-Plus-Plus protections in these various forums.” Susan Sell “ACTA is a threat to the future of a free and open Internet.” Alexander Furnas “Implementing the agreement could open a Pandora's box of potential human rights violations.” Amnesty International. “I will not take part in this masquerade.” Kader Arif, Rapporteur for the Anti-Counterfeiting Trade Agreement 2011 in the European Parliament Executive Summary As an independent scholar and expert in intellectual property, I am of the view that the Australian Parliament should reject the adoption of the Anti-Counterfeiting Trade Agreement 2011. I would take issue with the Department of Foreign Affairs and Trade’s rather partisan account of the negotiations, the consultations, and the outcomes associated with the Anti-Counterfeiting Trade Agreement 2011. In my view, the negotiations were secretive and biased; the local consultations were sometimes farcical because of the lack of information about the draft texts of the agreement; and the final text of the Anti-Counterfeiting Trade Agreement 2011 is not in the best interests of Australia, particularly given that it is a net importer of copyright works and trade mark goods and services. I would also express grave reservations about the quality of the rather pitiful National Interest Analysis – and the lack of any regulatory impact statement – associated with the Anti-Counterfeiting Trade Agreement 2011. The assertion that the Anti-Counterfeiting Trade Agreement 2011 does not require legislative measures is questionable – especially given the United States Trade Representative has called the agreement ‘the highest-standard plurilateral agreement ever achieved concerning the enforcement of intellectual property rights.’ It is worthwhile reiterating that there has been much criticism of the secretive and partisan nature of the negotiations surrounding the Anti-Counterfeiting Trade Agreement 2011. Sean Flynn summarizes these concerns: "The negotiation process for ACTA has been a case study in establishing the conditions for effective industry capture of a lawmaking process. Instead of using the relatively transparent and inclusive multilateral processes, ACTA was launched through a closed and secretive “‘club approach’ in which like-minded jurisdictions define enforcement ‘membership’ rules and then invite other countries to join, presumably via other trade agreements.” The most influential developing countries, including Brazil, India, China and Russia, were excluded. Likewise, a series of manoeuvres ensured that public knowledge about the specifics of the agreement and opportunities for input into the process were severely limited. Negotiations were held with mere hours notice to the public as to when and where they would be convened, often in countries half away around the world from where public interest groups are housed. Once there, all negotiation processes were closed to the public. Draft texts were not released before or after most negotiating rounds, and meetings with stakeholders took place only behind closed doors and off the record. A public release of draft text, in April 2010, was followed by no public or on-the-record meetings with negotiators." Moreover, it is disturbing that the Anti-Counterfeiting Trade Agreement 2011 has been driven by ideology and faith, rather than by any evidence-based policy making Professor Duncan Matthews has raised significant questions about the quality of empirical evidence used to support the proposal of Anti-Counterfeiting Trade Agreement 2011: ‘There are concerns that statements about levels of counterfeiting and piracy are based either on customs seizures, with the actual quantities of infringing goods in free circulation in any particular market largely unknown, or on estimated losses derived from industry surveys.’ It is particularly disturbing that, in spite of past criticism, the Department of Foreign Affairs and Trade has supported the Anti-Counterfeiting Trade Agreement 2011, without engaging the Productivity Commission or the Treasury to do a proper economic analysis of the proposed treaty. Kader Arif, Rapporteur for the Anti-Counterfeiting Trade Agreement 2011 in the European Parliament, quit his position, and said of the process: "I want to denounce in the strongest possible manner the entire process that led to the signature of this agreement: no inclusion of civil society organisations, a lack of transparency from the start of the negotiations, repeated postponing of the signature of the text without an explanation being ever given, exclusion of the EU Parliament's demands that were expressed on several occasions in our assembly. As rapporteur of this text, I have faced never-before-seen manoeuvres from the right wing of this Parliament to impose a rushed calendar before public opinion could be alerted, thus depriving the Parliament of its right to expression and of the tools at its disposal to convey citizens' legitimate demands.” Everyone knows the ACTA agreement is problematic, whether it is its impact on civil liberties, the way it makes Internet access providers liable, its consequences on generic drugs manufacturing, or how little protection it gives to our geographical indications. This agreement might have major consequences on citizens' lives, and still, everything is being done to prevent the European Parliament from having its say in this matter. That is why today, as I release this report for which I was in charge, I want to send a strong signal and alert the public opinion about this unacceptable situation. I will not take part in this masquerade." There have been parallel concerns about the process and substance of the Anti-Counterfeiting Trade Agreement 2011 in the context of Australia. I have a number of concerns about the substance of the Anti-Counterfeiting Trade Agreement 2011. First, I am concerned that the Anti-Counterfeiting Trade Agreement 2011 fails to provide appropriate safeguards in respect of human rights, consumer protection, competition, and privacy laws. It is recommended that the new Joint Parliamentary Committee on Human Rights investigate this treaty. Second, I argue that there is a lack of balance to the copyright measures in the Anti-Counterfeiting Trade Agreement 2011 – the definition of piracy is overbroad; the suite of civil remedies, criminal offences, and border measures is excessive; and there is a lack of suitable protection for copyright exceptions, limitations, and remedies. Third, I discuss trade mark law, intermediary liability, and counterfeiting. I express my concerns, in this context, that the Anti-Counterfeiting Trade Agreement 2011 could have an adverse impact upon consumer interests, competition policy, and innovation in the digital economy. I also note, with concern, the lobbying by tobacco industries for the Anti-Counterfeiting Trade Agreement 2011 – and the lack of any recognition in the treaty for the capacity of countries to take measures of tobacco control under the World Health Organization Framework Convention on Tobacco Control. Fourth, I note that the Anti-Counterfeiting Trade Agreement 2011 provides no positive obligations to promote access to essential medicines. It is particularly lamentable that Australia and the United States of America have failed to implement the Doha Declaration on the TRIPS Agreement and Public Health 2001 and the WTO General Council Decision 2003. Fifth, I express concerns about the border measures in the Anti-Counterfeiting Trade Agreement 2011. Such measures lack balance – and unduly favour the interests of intellectual property owners over consumers, importers, and exporters. Moreover, such measures will be costly, as they involve shifting the burden of intellectual property enforcement to customs and border authorities. Interdicting, seizing, and destroying goods may also raise significant trade issues. Finally, I express concern that the Anti-Counterfeiting Trade Agreement 2011 undermines the role of existing international organisations, such as the United Nations, the World Intellectual Property Organization and the World Trade Organization, and subverts international initiatives such as the WIPO Development Agenda 2007. I also question the raison d'être, independence, transparency, and accountability of the proposed new ‘ACTA Committee’. In this context, I am concerned by the shift in the position of the Labor Party in its approach to international treaty-making in relation to intellectual property. The Australian Parliament adopted the Australia-United States Free Trade Agreement 2004, which included a large Chapter on intellectual property. The treaty was a ‘TRIPs-Plus’ agreement, because the obligations were much more extensive and prescriptive than those required under the multilateral framework established by the TRIPS Agreement 1994. During the debate over the Australia-United States Free Trade Agreement 2004, the Labor Party expressed the view that it would seek to mitigate the effects of the TRIPS-Plus Agreement, when at such time it gained power. Far from seeking to ameliorate the effects of the Australia-United States Free Trade Agreement 2004, the Labor Government would seek to lock Australia into a TRIPS-Double Plus Agreement – the Anti-Counterfeiting Trade Agreement 2011. There has not been a clear political explanation for this change in approach to international intellectual property. For both reasons of process and substance, I conclude that the Australian Parliament and the Australian Government should reject the Anti-Counterfeiting Trade Agreement 2011. The Australian Government would do better to endorse the Washington Declaration on Intellectual Property and the Public Interest 2011, and implement its outstanding obligations in respect of access to knowledge, access to essential medicines, and the WIPO Development Agenda 2007. The case study of the Anti-Counterfeiting Trade Agreement 2011 highlights the need for further reforms to the process by which Australia engages in international treaty-making.

Vibrational spectroscopy of phthalocyanine and naphthalocyanine in sandwich-type (na)phthalocyaninato and porphyrinato rare earth complexes: Part 14. The infrared and Raman characteristics of phthalocyanine in “pinwheel-like” homoleptic bis[1,8,15,22-tetrakis(3-pentyloxy)phthalocyaninato] rare earth(III) double-decker complexes

The infrared (IR) spectroscopic data and Raman spectroscopic properties for a series of 13 “pinwheel-like” homoleptic bis(phthalocyaninato) rare earth complexes M[Pc(α-OC5H11)4]2 [M = Y and Pr–Lu except Pm; H2Pc(α-OC5H11)4 = 1,8,15,22-tetrakis(3-pentyloxy)phthalocyanine] have been collected and comparatively studied. Both the IR and Raman spectra for M[Pc(α-OC5H11)4]2 are more complicated than those of homoleptic bis(phthalocyaninato) rare earth analogues, namely M(Pc)2 and M[Pc(OC8H17)8]2, but resemble (for IR) or are a bit more complicated (for Raman) than those of heteroleptic counterparts M(Pc)[Pc(α-OC5H11)4], revealing the decreased molecular symmetry of these double-decker compounds, namely S8. Except for the obvious splitting of the isoindole breathing band at 1110–1123 cm−1, the IR spectra of M[Pc(α-OC5H11)4]2 are quite similar to those of corresponding M(Pc)[Pc(α-OC5H11)4] and therefore are similarly assigned. With laser excitation at 633 nm, Raman bands derived from isoindole ring and aza stretchings in the range of 1300–1600 cm−1 are selectively intensified. The IR spectra reveal that the frequencies of pyrrole stretching and pyrrole stretching coupled with the symmetrical CH bending of –CH3 groups are sensitive to the rare earth ionic size, while the Raman technique shows that the bands due to the isoindole stretchings and the coupled pyrrole and aza stretchings are similarly affected. Nevertheless, the phthalocyanine monoanion radical Pc′− IR marker band of bis(phthalocyaninato) complexes involving the same rare earth ion is found to shift to lower energy in the order M(Pc)2 > M(Pc)[Pc(α-OC5H11)4] > M[Pc(α-OC5H11)4]2, revealing the weakened π–π interaction between the two phthalocyanine rings in the same order.

Tuning the valence of the cerium center in (Na)phthalocyaninato and porphyrinato cerium double-deckers by changing the nature of the tetrapyrrole ligands

A series of 7 cerium double-decker complexes with various tetrapyrrole ligands including porphyrinates, phthalocyaninates, and 2,3-naphthalocyaninates have been prepared by previously described methodologies and characterized with elemental analysis and a range of spectroscopic methods. The molecular structures of two heteroleptic \[(na)phthalocyaninato](porphyrinato) complexes have also been determined by X-ray diffraction analysis which exhibit a slightly distorted square antiprismatic geometry with two domed ligands. Having a range of tetrapyrrole ligands with very different electronic properties, these compounds have been systematically investigated for the effects of ligands on the valence of the cerium center. On the basis of the spectroscopic (UV−vis, near-IR, IR, and Raman), electrochemical, and structural data of these compounds and compared with those of the other rare earth(III) counterparts reported earlier, it has been found that the cerium center adopts an intermediate valence in these complexes. It assumes a virtually trivalent state in cerium bis(tetra-tert-butylnaphthalocyaninate) as a result of the two electron rich naphthalocyaninato ligands, which facilitate the delocalization of electron from the ligands to the metal center. For the rest of the cerium double-deckers, the cerium center is predominantly tetravalent. The valences (3.59−3.68) have been quantified according to their LIII-edge X-ray absorption near-edge structure (XANES) profiles.