Metal Fasteners Research Articles

Preliminary Design Proposals for Dovetail Wood Board Elements in Multi-Story Building Construction

Adhesives and metal fasteners play important roles in the composition and connections of engineered wood products (EWPs) such as cross-laminated timber and glue-laminated timber in the building construction industry. However, due to their petroleum-based nature, adhesives can cause toxic gas emissions, while metal fasteners compromise the end-of-life disposal and reusability of EWPs. These issues adversely affect the sustainable material properties of EWPs. Numerous studies have been conducted in the literature on the technological, ecological, social, and economic aspects of EWPs in construction with different construction solutions, but no studies have been conducted to evaluate the technical performance of dovetail wood board elements (DWBE) in multi-story or tall building construction. This study focuses on adhesive- and metal fastener-free DWBE as sustainable material alternatives for ecologically sensitive engineering solutions. Various preliminary design proposals are presented for DWBE using architectural modeling programs as an environmentally friendly approach intended for use in the timber construction industry. The research findings are based on a theoretical approach that has not yet been practically tested but is proposed considering existing construction practices that need further investigation, including technical performance tests. It is believed that this paper will contribute to the promotion and diffusion of DWBE for more diverse and innovative architectural and structural applications, particularly in multi-story timber building construction, as one of the key tools in tackling climate change challenges.

The Filing Cabinet: A Vertical History of Information

The Filing Cabinet: A Vertical History of Information

Shear capacity of timber-to-timber connections using wooden nails

ABSTRACT With increasing environmental concerns, the building sector must rethink the selection of building materials not only for structural members but also for connections. Densified wooden nails might become an alternative to metallic fasteners, at least in applications with lower structural requirements. However, their structural behaviour in timber-to-timber connections is not yet systematically studied. This paper presents a series of 90 shear tests to explore the shear capacity and slip modulus of timber-to-timber connections with wooden nails. Specimens with different nail dimensions, different nail orientations, and different nail arrangements were investigated. A typical three-member push-out test setup was adopted where the wooden nails were oriented perpendicular or inclined to the shear plane. Specimens with inclined nails exposed to shear and tensile forces showed a higher shear resistance due to the activated tensile capacity of the wooden nails. Failure of the wooden nails was predominantly observed when the nails were loaded in tension. This means that the interface between the wooden nails and the timber did not fail. Based on the results from the shear tests, an analytical model was developed to predict the load bearing capacity of timber-to-timber connections exposed to bending stresses. The analytical model was validated with experimental investigations.

Effects of Metal Fasteners of Ventilated Building Facade on the Thermal Performances of Building Envelopes

Thermal bridging in the building envelope is one of the main causes of energy losses, even in high-efficiency ventilated building façades. In this study, the effects of point-thermal bridges attributed to metal fasteners on the heat transferred through different types of bricks were predicted. All the structural details of the substrate wall were included as well. This was accomplished with a multi-scale, finite element modelling approach used to enhance the thermal insulation efficiency of the building envelope. The effects of the metal fastener length, diameter, density and location were examined to elucidate any opportunity to minimize the heat losses caused by thermal bridging. The results demonstrated that increases in the lengths of fasteners yielded higher energy losses compared with those generated when the diameter increased. Additionally, metal fasteners caused higher energy losses by up to 30% when fixed on mortar, compared with the energy losses incurred when they were fixed on bricks.

Investigation of crevice corrosion of metallic fastened joints in carbon fiber reinforced polymer (CFRP) exposed to coastal seawater

Purpose The purpose of this paper is to study the susceptibility of these three commonly used corrosion resistance fasteners in seawater. For a more practical scenario, a local Atlantic coastal seawater as received was used. Design/methodology/approach Carbon fiber reinforced polymer (CFRP) was fabricated with T700 carbon fiber (Toray Inc.) and VE8084 vinyl ester resin (Ashland) to make a unidirectional composite panel of thickness 1.8 mm. A conductive paint was applied to one of the sample edges that was perpendicular to the fiber direction, providing an electrical contact with carbon fibers to connect a copper wire. This external electric connection was used for potential measurements of both the open circuit potential (OCP) of the CFRP sample, and the mixed potential of the fastened set: consisting of the CFRP and the metallic fastener fastened to it. Three common fastener alloys were selected: 316SS, Monel and Titanium. For this purpose, a high impedance voltmeter was used in conjunction with a saturated calomel reference electrode. Measurements were taken daily. For longer time measurements, a four-channel high impedance analog data logger was used with 30 min sampling rate. Findings For both 316SS and Monel fastened sets, crevice corrosion occurred inside the occluded regions of the set, when immersed in coastal seawater. The attack was more severe for 316 stainless steel set. An isolated island attack of faceted surfaces morphology was seen for 316SS set. While, a circular ring of preferential grain boundary attack appeared for Monel set, indicating an IR (voltage) drop mechanism is more likely operating. Titanium-fastened sets showed high resistance to crevice corrosion when simmered in seawater. However, for long-time exposure, the sets became more susceptible to crevice corrosion attack supported by CFRP attachment (oxygen reduction reaction taking place at the carbon fibers). Originality/value Evidently, titanium, stainless steels and Monel are good candidates for galvanic corrosion resistance. However, their susceptibility to crevice corrosion when coupled with CFRP is a new challenging topic that needs further investigation. This is very important today because the vast application witnessed for CFRP material. This work involves developing an original methodology for this kind of investigation and was done at advanced laboratories of SeaTech at Florida Atlantic University by the Atlantic coastline.

Using Radio‐Frequency Fields for Local Heating and Curing of Adhesive for Bonding Metals

Lightweighting of metal structures can be achieved by replacing metallic fasteners with thermosetting adhesives. However, thermal curing of adhesives to bond metals in an oven can lead to distortions due to mismatched coefficients of thermal expansion, thereby compromising the structural integrity. Targeted heating of the adhesive can be utilized to minimize distortions and residual stresses in metal‐composite assembly. Herein, it is shown that rapid heating of carbon nanoparticles in the presence of radio‐frequency (RF) electromagnetic fields can be used to cure nanocomposite adhesives for bonding metal substrates selectively. Using the metal components of a structure as a part of an RF circuit, electric fields are generated through a carbon‐nanofiller loaded adhesive, which then volumetrically heats and cures. Comparable lap‐shear strengths and adhesive peel resistance are measured for RF‐ and oven‐cured composites. RF‐cured multimaterial bonding specimens (aluminum‐to‐steel) show minimal distortion, resulting in ≈590% higher fracture energies in peel mode as compared with oven‐cured specimens.

Impact of moisture cycling on lateral resistance of resin-impregnated compressed beech nails in radiata pine timber

ABSTRACT Resin impregnated wood nails create an opportunity to use more renewable materials in place of metal fasteners, but there are few data on the effects of moisture cycling on performance. The properties of resin impregnated, compressed beech nails that had been subjected to repeated wetting and drying were compared with steel nails using radiata pine lumber. Sections cycled between ∼12 and ∼50% moisture content were destructively tested in shear. Capacity increased slightly with exposure to one moisture cycle for both connector types. Significant negative effects on wooden nail stiffness were only observed after 5 or 7 moisture cycles. Metal nails failed in a ductile fashion while the timber connectors failed in a brittle mode. The results suggest that wood fasteners can withstand some wetting, but repeated moisture cycling will be detrimental to performance.

Cyclic Behavior and Modeling of Bolted Glulam Joint with Cracks Loaded Parallel to Grain

Under varying humidity and temperature conditions, with the constraint of metal fasteners to wood shrinkage, cracks along the bolt lines are generally observed in bolted glulam joints. A three-dimensional (3D) numerical model was established in software package ANSYS to investigate the cyclic behavior of bolted glulam joints with local cracks. A reversed cyclic loading was applied in the parallel-to-grain direction. The accuracy of numerical simulation was proved by comparison with full-scale experimental results. Typical failure modes were reproduced in the numerical analysis with the application of wood foundation zone material model and cohesive zone material model. The effect of crack number and length on the hysteretic behavior of bolted glulam joints was quantified by a parametric study. It was found that initial cracks impair the peak capacity and elastic stiffness of bolted glulam joints significantly. More decrease in capacity was observed in joints with more cracks, and longer cracks affect elastic stiffness more dramatically. Moreover, with the existence of initial cracks, the energy dissipated and equivalent viscous damping ratio of bolted joints are reduced by 24% and 13.3%, respectively.

Металлические застежки богослужебных книг новосибирских старообрядцев

The article analyzes the newly discovered monuments of the Old-Believer book and artistic culture—fasteners of old printed and manuscript liturgical books of the 18th-19th centuries. In 1990s, these fasteners were kept in a small box in a prayer house of the Old-Believers of the Fedoseevsky community in Novosibirsk. It was strictly forbidden to keep service books open, which is observed up to the present time (explanation: “so as not to defile something unclean”). For this reason, books were closed and snapped into place. Observations of the way of life of the Novosibirsk Old-Believers-Fedoseevites allowed us to conclude that the community members treated not only books, but also metal fasteners as sacred objects. The tradition to snap liturgical books continued to live in the years of the USSR until the end of the 1990s, when the community ceased to exist due to the demolition of the prayer house. As a result of the analysis, the classification of the types offasteners, depending on the shape, ornaments and execution technique, was carried out. Some general patterns of ornamentation of fasteners are identified, possible vectors of cultural contacts that influenced the design (medieval Russia and the Middle East) are indicated, and the author’s interpretations of religious meanings imprisoned in the ornaments of these works of applied art are provided. The need to protect objects of worship and everyday life from “evil”, the depicted ornamentalfigures allow us to assume precisely the apotropic (protective) purpose of the fasteners under consideration. Paradoxical as it may seem, the discovered materials also make it possible to draw a parallel with the well-known ancient Slavic archaeological materials, attributed by archaeologists to Pagan amulets.

Coupled nonlinear-damage finite element analysis and design of novel engineered wood products made of oak hardwood

This paper presents a comprehensive experimental and numerical investigation to design novel engineered wood products (EWPs), namely adhesive-free laminated beams (AFLB) and adhesive-free cross-laminated timber (AFCLT) panels, for the first time. Thermo-mechanically compressed wood (CW) dowels were used as a joint element as an alternative to the traditional glue and metallic fasteners. The following structural elements were studied: (1) solid timber beams, (2) middle-scale and large-scale three-layer AFLB, (3) timber-to-timber connections and (4) AFCLT panels. In addition, a predictive coupled nonlinear-damage model was proposed as a predictive and powerful tool design to reduce expensive experimental tests. The main mechanical characteristics and performance of the designed EWPs are assessed experimentally and addressed in the paper. Furthermore, the accuracy and the performance of the developed FE model were verified against experimental results from the studied example showing a fairly good prediction of the non-linear behavior as well as the modes of failure and its growth. Finally, the validated FE model was used to carry out a parametric study of the influential design parameters and some design recommendations are made.

Experimental Assessment of Thermal Performance and Bridging Effects of Low-Cost Sandwich Panels under a High-Temperature Impinging Jet.

Sandwich panels are commonly used across industries for their ability to bear structural and thermal loads. In this paper, a panel chamber matching apparatus was designed to investigate the thermal performance of eight steel-based panels by exposing them to an impinging jet at approximately 550 °C for 30 min. Three types of low-cost materials (polycrystalline filaments, silica aerogel, and aluminum silicate) were used as the insulation core. The temperature of the panel surfaces was measured, as well as the metallic fasteners, including bolts, nails, battens, seams, and angle iron, to examine their thermal bridge effects. Major conclusions include the following: first, the maximum temperature on the impinged surface was consistent among all 20 cases, whereas that of the surface under free convection varied, ranging from 41 to 120 °C, depending on the core and thermal bridges. Second, most of the highest temperatures on opposite surfaces were caused by a section of bare angle iron, and this bridging effect could be significantly reduced by up to 50 °C using a few layers of cloth, although the improvement could be temporary. Bolts and nails were less effective as thermal bridges, while the battens could be more effective. Third, the estimated heat flux of all specimens ranged from 167 to 331 W·m−2.

Shipbuilding and maritime activity on the eve of mechanization: Dendrochronological analysis of the Akko Tower Shipwreck, Israel

The 19th century was an era of increasing mechanization and globalization, which transformed maritime networks and shipbuilding in and beyond the Mediterranean. Shipwrecks offer valuable physical evidence of such maritime connectivity and evolving shipbuilding techniques but must be dated within a high-resolution timeframe to be synchronized with, and thereby enhance, historical records. We focus here on high-resolution dating of the Akko Tower Shipwreck, the remains of an Ottoman merchant brig found inside the harbor of Akko, Israel. We use dendrochronology, 14C wiggle-matching, and Bayesian chronological modeling to determine that the ship was likely constructed in the mid-1850s, and therefore called at Akko’s harbor after the town’s 1840 bombardment, a period of decline traditionally under-studied in Ottoman historical narratives. Using dendroprovenancing methods, we find that the ship’s hull used timbers from the Anatolian Black Sea region, although it was built in the French construction tradition, and used British metal rigging and fasteners, which reflect shifting Anglo-French influence and socioeconomic interconnections with the Ottoman Empire during the 19th century.The Akko Tower Shipwreck is the first shipwreck from Israel to be dendrochronologically dated and provenanced. Our results show how dendrochronology and Bayesian chronological modeling can be used successfully not only for high-precision dating, but also for untangling the shipbuilding processes and the socioeconomic networks that made ship construction possible. We also re-evaluate East Mediterranean oak sapwood datasets and develop an approximate new sapwood model that provides more robust estimates of felling dates for tree-ring analysis of this region’s oak wooden cultural heritage.

중복판과 인경본 비교를 통한 고려대장경판 보존관리

The Goryeo Tripitaka woodblocks are the only extant Tripitaka woodblocks carved in Chinese characters, and are included on UNESCO’s Memory of the World Register. 112 of the 81,352 woodblocks that constitute the Goryeo Tripitaka are duplicates a term that refers to woodblocks of which two or more copies exist. 50 of the 112 duplicate woodblocks are thought to be first editions dating from the reign of Goryeo king Gojong (1236~1251); as such, they are highly valuable. These duplicates show various damage due to conservation processes or repeated printing, providing important information about the preservation and repair history of the blocks. In this article, I analyze the current status of duplicate woodblocks and examine the history of their preservation through comparison with printed texts.BR I begin with brief examination of the current status of duplicate woodblocks. The sutra that accounts for the highest number of duplicates is the Prajñāpāramitā Sutra. But since examination of the entire sutra is not possible, I take a sample of 15 blocks and examine them for signs of damage including whether end blocks (maguri) and metal fasteners (jangseok) are present, and whether repairs have been performed. I then examine prints made from these woodblocks, focusing in particular on whether blocks used to make prints in 1381 were still being used in 1865 by gauging the level of similarity between printed copies from each of these two periods.BR I compare the sutra now in the collection of Otani University, which was printed in 1381, with the copies at Woljeongsa Temple and Oseam Hermitage, which were printed in 1865, and with the copies at Tongdosa and Haeinsa temples, printed in 1899. In order to gauge changes that occurred between 1381 and 1865, I analyze all 130 volumes of Prajñāpāramitā Sutra, finding that no changes have occurred. This indicates that the Goryeo Tripitaka woodblocks were fundamentally managed in a stable manner until 1865. However, comparison of printed copies does reveal traces of repair to heavily damaged duplicate blocks. The Woljeongsa and Oseam copies show the following signs of repair in duplicate blocks in places where the original blocks have been worn or their corners damaged: cases where damaged parts have been cut off in order to prevent further damage; cases where repair has been attempted after cutting; cases where repairs have been completed after cutting; and cases where repaired parts have been damaged again after repair. These various examples of repair indicate that such measures were taken continuously throughout the Joseon period, especially after 1865.BR Moreover, examples of supplementary carvings show us that a considerable proportion of duplicate blocks dating from the 1899 prints onwards were supplementary carvings with boundary lines between the columns of characters. I believe these replacement carvings with boundary lines were produced after 1865, in cases where woodblocks that had been repaired were nonetheless deemed unsuitable for printing.

Contribution to mechanical fasteners for composite structures – An automated industrial approach

Current fastening technologies implemented in the composite structures of car body applications show various disadvantages compared to an interference-fit joint. For example, adhesive bonding requires clean and pre-treated surfaces and metallic fasteners are prone to galvanic corrosion. This work investigates the process of an interference-fit joint (connection) comprising a fiber-reinforced thermoplastic insert pressed into a pre-drilled hole in a polymeric composite structure. With the insert being oversized and the hole undersized, interface pressure is generated. Pressure in radial direction is leading to friction which in turn is giving the insert resistance against pull out. The connection is functionally evaluated by comparing both the pullout force curves and the injection force curves for three different levels of interference. Major target is a prediction of the resulting pull out force based on the injection process. Furthermore, a process capability evaluation of the connection is presented.Since the environmental conditions of a car manufacturer’s body shop require highly automated processes, the connection should be implemented in a fully automated manner. The process is conducted by a robot controlled device fulfilling relevant targets of process reliability, capability and reproducibility. Additionally, the whole equipment is designed with regards to body shop facilities allowing to transfer the test equipment into a production environment.

The challenges of bonding composite materials and some innovative solutions

In this article we first look at the benefits of composite materials and why they have become so popular, as well as the challenges of joining composite materials together and the advantages that adhesives and tapes have over traditional metal fasteners. We also explore advice on choosing the right adhesive to use and what parameters to consider as well as comparing some of the new adhesives that are being used to bond composite materials, whilst evaluating the advantages some chemistries have over others. We also detail two recent Case Studies where Techsil has worked with manufacturers using carbon fiber composite parts in their product assemblies to overcome challenges in bonding their parts together. The first using a clear epoxy to provide an extremely strong butt joint between two carbon fiber parts. The second using a black epoxy to pot anchor points in a carbon fiber part to allow the component to be easily drilled and tapped so that metal fasteners could be used at the joints.

Mademoiselle Angélique Caroline Milliet: Did She Invent the Steel Skeleton Petticoat?

In 1856 the Frenchwoman Angélique Caroline Milliet invented the first steel skeleton petticoat or cage. She received patents in France, Belgium and England and used her patents to sue competitors for infringement. In 1861 she sold her patents for a large sum to the American brothers and skirt manufacturers W. S. & C. H. Thomson. These brothers founded big crinoline factories in New York, London, Paris, Brussels and Annaberg. The mass-produced Thomson crinolines became famous all over the world. The Dutch Amsterdam Museum owns an original skeleton petticoat designed by A. C. Milliet. It is stamped and looks exactly like the illustrations of the French and English patents. This unique design has a built-in bustle and the circumference of the hoops can be altered according to the requirements of the wearer. American hoop-skirt manufacturers, like Thomson, managed to improve the Milliet design with their patented metal fasteners to secure the horizontal hoops to the vertical tapes. During the 1860s the Thomson cages, which were manufactured by the thousands every day, conquered the fashionable world.

Metal Fasteners for the Local Fashion Accessories Industry in Ghana

The fashion industry in Ghana has evolved over time and has created a large market for both the producers and retailers. Ghanaian fashion designers like Mawuli Okudzeto, Genesis Clothing and Kofi Ansah to mention but a few have been able to capture pure African values in their designs. Companies like Akosombo Textiles and TexStyles Ghana Ltd, Vlisco and Woodin are daily producing materials that are becoming so useful to local fashion designers and they in turn are producing the styles that we also enjoy wearing. Ghanaian designers are also making fashion accessories like bags, shoes, jewellery; belts, among others, to match the clothes that they produce. Although Ghanaian fashion designers use metal fasteners in designing clothes and accessories, unfortunately, most of these fasteners are imported products that do not have any philosophical relation with the Ghanaian people. Even worse, the jewellery industry does not consider this venture as a niche market and also as a platform to support local fashion designers to create a holistic Ghanaian concept in what we wear. This paper explored the possibility of producing metal fasteners for Ghanaian fashion accessories industry using the Practice-based research method. The inspiration for the project was the popular Ghanaian Akinkra symbols. The result of the study revealed that metal fasteners could be produced in the studio with local concepts giving a totality of Ghanaian fashion concepts. The study recommends that techniques for the production could also be improved by adopting new production practices such as laser cutting and investment casting methods.

Eliminating Fastener Thermal Bridging in Low Slope Roofs: Energy Efficiency Savings versus Installation Costs

Low-slope roofing assemblies include a wide range of insulation and single ply membrane attachment methods. Previous studies have shown that mechanical attachment using metal fasteners leads to significant thermal bridging and consequent loss of insulation value and reduction of long term thermal efficiency. This study calculates the costs associated with mechanical attachment in terms of lost insulation value, increased long-term energy costs, and the material and labor costs associated with installation of these common systems. Energy efficiency reductions using metal fasteners were modeled for eight US cities in a range of climate zones. From the data, it was possible to calculate target costs (labor plus materials) that would make adhered systems cost effective. There are many options available to adhere single ply roof system components, such as solvent-based adhesives and low-rise urethane foams, together with different application approaches such as broom, spray, and ribbon methods. The cost targets derived in this study can help optimize the use of such materials and application methods such that the thermal bridging due to fasteners could be substantially reduced or eliminated.

Corrosiveness of Thermally Modified Wood

Thermally modified wood is becoming commercially available in North America for use in outdoor applications. While there have been many studies on how thermal modification affects the dimensional stability, water vapor sorption, and biodeterioration of wood, little is known about whether thermally modified wood is corrosive to metal fasteners and hangers used to hold these members in place. As thermally modified wood is used in outdoor applications, it has the potential to become wet which may lead to corrosion of embedded fasteners. Here, we examine the corrosiveness of thermally modified ash and oak in an exposure test where stainless steel, hot-dip galvanized steel, and carbon steel nails are driven into wood and exposed to a nearly 100% relative humidity environment at 27 °C for one year. The corrosion rates were compared against control specimens of untreated and preservative-treated southern pine. Stainless steel fasteners did not corrode in any specimens regardless of the treatment. The thermal modification increased the corrosiveness of the ash and oak, however, an oil treatment that is commonly applied by the manufacturer to the wood after the heat treatment reduced the corrosiveness. The carbon steel fasteners exhibited higher corrosion rates in the thermally modified hardwoods than in the preservative-treated pine control. Corrosion rates of galvanized fasteners in the hardwoods were much lower than carbon steel fasteners. These data can be used to design for corrosion when building with thermally modified wood, and highlight differences between corrosion of metals embedded in wood products.

The Effect of the Wood Defects on Fire Resistance

In the case of charcoal speeds, the defects of the wood and the effect of the metal fixing elements are not taken into account. The aim of our research was to analyze and investigate the effect of wood defects and fasteners on fire resistance. During the experiments we investigated the effect of the defects in the wood and the effect of the metal fasteners on the fire resistance. In the first part of the experiments we examined the effect of wooden defects (knots, thread direction, cracks, insect repellent) on fire resistance. We assumed that the higher hardness or density of the knots and the different fiber direction would facilitate the burning of the wood in the vicinity of the knot. In our experiments, we also examined the effects of cracks and insect pests. The second part of our experiment was to test the switching elements under the effect of heat load.res.