Types Of Fasteners Research Articles

Load-bearing capacity and characteristic forms of destruction of furniture joints made with rastex 15 and P-10 clamex fasteners

Load-bearing capacity and characteristic forms of destruction of furniture joints made with rastex 15 and P-10 clamex fasteners. The study tested the relationship between the load and angular deflection in furniture joints. The tests were carried out for two types of fasteners and five types of materials: chipboard, MDF, hardwood plywood, glued pine boards and glued oak boards. The furniture joint samples contained two fasteners preloaded only with a bending moment (without application of shear forces). The results were converted per single fastener specifying: its maximal load capacity, 50 mrad (2.9°) limit deflection and rigidity coefficient. It was found that rigidity is a better structural property of the tested joint types than their load capacity. As far as rigidity is concerned, the most durable is the combination of oak glued board – rastex 15 fastener (13.2 Nm bending moment per fastener), while the least durable combination is chipboard – clamex P-10 fastener (4.8 Nm bending moment per fastener). Photographic documentation of damaged furniture joint samples was prepared and analysed. In case of chipboard and MDF combinations (where the load is determined by the combined material), the combined boards suffer a disastrous damage, while in combinations of plywood boards and pine or oak glued boards, (where the capacity is determined by the fastener), both clamex P10 and rastex 15 fasteners are damaged.

Reliability and profitability of rail fastenings

The railroad is intended for transportation of goods and passengers. Than freight density of the railroad, subjects it more is more profitable. Efficiency and reliability of a track in many respects depends on a good shape rails, cross ties and fastenings. Let’s consider fastenings connecting rails with cross ties. KB and Foslo rail fastenings are generally applied at the Latvian railway. Fastenings of KB found to themselves a good reputation any more one decade. These fastenings represent a type of a separate fastening where by means of bolts separately connect a rail sole lined and other bolt – a lining to a cross tie. Foslo fastening for the Latvian railroad is rather new type of a fastening. In this fastening there is one bolt and a spring which holds together both a rail sole, and a cross tie. And here some years dispute – what - a fastening better does not cease. The article deals with the positive and negative properties of these fastenings.

Bank protection structures of the cascade of water reservoirs of the Vilia-Minsk water system

The data of field studies of shore protection structures in the reservoirs of the Vilia-Minsk water system are given, the current state of various types of fastenings is assessed with the reasons for their destruction and the extent of deformation. The article presents the results of field observations of coastal shelter-type structures. It is shown that the most common anchorages of banks and slopes is to protect the surface of slopes in the form of reinforced monolithic or precast slabs. It is determined that the deformations of the slope anchorages are most often represented by the opening of inter-tile construction, temperature and sedimentary seams (the opening width is registered to 0.35 m) which develop under the complex influence of wind waves, fluctuations in levels and other factors. Subsequently, the deformation of the exposed seams lead to the destruction of the attachment. Experimentally, on the basis of physical modeling of deformations of slopes made in the hydrotechnical laboratory of the Belarusian National University on models of soil supporting structures protected by reinforced concrete fastening, it was established that as a result of opening the seams of the plates, the sand-gravel preparation and the formation of sinuses and niches in the body of the support structure occur , which leads to significant processing of the ground slope. The coastal protection structures of the active type in the form of laid and beach slopes are considered. The dependencies on the calculation of slope deformations are obtained on the basis of a generalization of the data of field observations.

Structural behavior of the stiffened double-skin profiled composite walls under compression

Steel-concrete composite walls have been proposed and developed for applications in various types of structures. The double-skin profiled composite walls, as a natural development of composite flooring, provide structural and architectural merits. However, adequate intermediate fasteners between profiled steel plates and concrete core are required to fully mobilize the composite action and to improve the structural behavior of the wall. In this research, two new types of fasteners (i.e., threaded rods and vertical plates) were proposed and three specimens with different fastener types or fastener arrangements were tested under axial compression. The experimental results were evaluated in terms of failure modes, axial load versus axial displacement response, strength index, ductility index, and load-strain relationship. It was found that specimen with symmetrically arranged thread rods sustained more stable axial strain than that with staggered arranged threaded rods. Meanwhile, vertical plates are more suitable for practical use since they provide stronger confinement to profiled steel plate and effectively prevent the steel plate from early local buckling, which eventually enhance the composite action and increase the axial compressive capacity of the wall. The calculation methods were then proposed and good agreement was observed between the test results and the predicted results.

Experimental and analytical study of an CF-PEEK Fastener all composites single-lap shear joint under static and fatigue loading

This paper presents a detailed experimental study on carbon fibre (CF) polyether etherketone (PEEK) composite fasteners designed to join conventional high performance composites (CFRP). The failure mechanisms of two CF-PEEK fasteners with countersunk heads joining two laminate plates in a single-lap configuration were investigated under static (tensile) and cyclic loading (tension–tension). The failure process of the bolted joints is described in detail using acoustic emission and microscopic cut views. For comparison the CF-PEEK fasteners were replaced by metal fasteners (Titanium) under the corresponding conditions and loadings. The experimental results are in good agreement with the newly developed “closed-form” model up to the damage point of the joints. This enhanced analytical approach is a closed-form extension of the spring-based method, where bolts and laminates are represented by an arrangement of springs and masses. The model covers in all variables influencing the joint behaviour, such as fastener position, joint material, fastener type, hole diameter, joint thickness, bolt-hole clearance, and bolt torque.

The Effect of Fastener Type on the Connection Performance of Bolted Joints in Composite Laminates

An experimental investigation was conducted to determine the effect of fastener type on the connection performance of double lap-type single bolted composite joints. The joints with blind bolts and high lock bolts were tested separately by static tests and dynamic tests. ASTM D 5961 was adopted by static tests, and tension-compression reversed force/stress ratio, R=-1, was selected to evaluate the fatigue tests. The appropriate levels of fatigue stress were determined by the ultimate bearing strength of the fastener structure obtained from the static tests. The bearing stress and the fatigue life (S-N) date of different fastener types of specimen were presented and the relationship between fastener types and fatigue life were obtained. The experimental results showed that the connection performance of the blind bolted joint was better than that of the high-locking bolted joint. The ultimate bearing strength of the blind bolted joints was 1.9% higher than that of the high lock bolted joints, and the fatigue life of the blind bolted joints was 1-2 orders of magnitude higher than that of the high-locking bolted joint under the same cyclic stress.

Influence of number of layers on embedment strength of dowel-type connections for glulam and cross-laminated timber

The purpose of this paper is to provide a better understanding of the embedment behaviour of dowel type fasteners in laminated timber. The influence of the number and thickness of the lamellas on embedment strength in glued laminated timber (GLT) and cross-laminated timber (CLT) is experimentally investigated and discussed. Full hole embedment tests in compression were conducted with specimens of equal properties (thickness, density), only with changes in the investigated parameter.The results show the embedment strength in CLT is influenced by locking effect of thinner crossed layers. In addition, the densification of crossed layers—the hardening effect—is clearly pronounced and leads to higher embedment stresses and strengths at larger dowel displacements. Stiffness values are presented in this paper but not discussed.The comparison of embedment strength values with well-known empirical models showed good agreement for GLT. In contrast, the results for CLT were far below the values calculated with existing models and are discussed in the paper.The findings are important to provide a safe and efficient joint to achieve more efficient use of CLT products.

Mobilya köşe birleştirmelerinde demonte tipi bağlantı elemanlarının moment kapasitesine etkileri

Bu çalışmada, mobilya köşe birleştirmelerinde kullanılan demonte tipi bağlantı elemanlarının moment kapasitesine etkileri araştırılmıştır. Deney örnekleri ahşap esaslı kompozit levhalardan, sentetik reçinelerle kaplanmış yonga levha (YL-Lam) ve lif levhalardan (MDF-Lam) hazırlanmıştır. Bağlantı elemanı olarak metal L, plastik T, metal T ve ay bağlantı elemanı olmak üzere dört farklı bağlantı elemanı kullanılmıştır. Deney örnekleri, kullanımları sırasında etkisinde kalabilecekleri kritik yükler göz önüne alınarak statik yük altında basma ve çekme deneyine tabi tutulmuştur. Deney sonuçlarına göre, diyagonal basma deneyinde moment taşıma kapasitesi değeri; bağlantı elemanı çeşidine göre en yüksek değer, metal L bağlantı elemanı ile birleştirilen deney örneklerinde, en düşük değer ise Ay bağlantı elemanında tespit edilmiştir. Ahşap esaslı kompozit levha-bağlantı elemanı tipi ikili etkileşimlerindeki diyagonal çekmede, en yüksek değer MDF-Lam ile metal L bağlantı elemanı hazırlanan deney örneklerinde, en düşük değer ise YL-Lam ile ay bağlantı elemanı ile hazırlanan örneklerde tespit edilmiştir Bu veriler ışığında, mobilya elemanları köşe birleştirmelerinde MDF-Lam malzemesi ile metal L bağlantı elemanı kombinasyonu uygulanabilir.

Investigation of Wood Shear Walls Subjected to Lateral Load

This paper summarizes results of 15 tests from the first phase of a study on lateral resistance of wood-frame shear walls without openings, constructed with traditional dimensional lumber and Oriented Strand Board panels (OSB). The next phases considered shear walls with strap ties, bracings, and uplift are presented in subsequent papers. Traditional shear wall construction across most of the United States includes wall studs spaced 40.5 cm (16 in) on center where the sheathing is attached with 6d, 50 mm × 2.85 mm (2 in × 0.113 in) smooth shank penny nails spaced at 150 mm/300 mm (6 in/12 in) at the edge and field, respectively. Likewise, the walls are commonly attached to the foundation with anchor bolts spaced 1.8 m (6 ft) on center. This study alternates the type, number, and spacing of these different connections, as well as the length of the wall to improve understanding of wood shear wall behavior due to lateral loads and to determine design methodologies which improve wood-frame construction performance. Overall results indicate that wall strength improved for each of the following modifications: doubling the base plate, decreasing anchor bolt spacing, increasing washer size, fastener type and spacing. Design value and deflection were determined based on SDPWS-2015 and compared to the shear capacity and ASCE 7 deflection limit.

On the Reliability of Finite-Element Evaluation of the Dynamic Interaction of a Structure with the Base

We analyze the characteristic errors of the finite-element modeling of soil massifs by an example of the problem of vibrations of a layer on the rocky base for various types of fastening of the lateral boundary: rigid fixture, free boundary, acoustic boundary, and acoustic boundary with a column of the base. The first error is connected with the assumption that, for large distances of the boundary from the structure, the boundary conditions do not affect its behavior. The second error is caused by the use of a constant in height) elasticity modulus for a homogeneous layer of soil. The size of the domain used for modeling guaranteed the boundedness of the zone of dislocation displacements near the boundary and constant displacements in the central part of the layer. However, these displacements differed from each other and from the exact solution given by the elasticity theory. This is explained by the specific features of taking into account the effect of damping within the framework of the applied software.

Performance of dowel-type fasteners and notches for hybrid timber structures

One of the most popular Timber-Concrete connection types is the dowel type fastener, due to many factors, such as for example, simplicity, low cost and adequate performance in most conditions. This connection type was traditionally used in timber structures and was adopted for composite structures from the early ages. The basic phenomena governing the mechanical behavior of timber-timber and timber-concrete connections with dowel type fasteners are similar, however, the last show some relevant specificities due largely to the presence of concrete. Such specificities have a non-negligible influence in the performance and consequently in modelling and design. In this paper such specificities are discussed, as well as, their consequences in the modelling. Based on this analysis proposals are made for models to estimate the connections’ load carrying capacity and slip modulus. Additional the existing knowledge about the performance of notched connections is summarized. Therefore, also values for important design parameters such as minimum values for the geometry, values for the slip modulus and possible failure modes of a notched connection are given.

Determination of the influence of the tape tension and the detachment force of the Velcro fastener in the rehabiliation footwear

The object of research is the constructive parameters of orthopedic postoperative footwear, which are based on complex theoretical and experimental studies of the effect of the upper outer surface of the foot on the top of the footwear during using. One of the most problematic places is the lack of knowledge of the conditions of interaction of the supporting belts with the Velcro fastener and the outer part of the freebie. It is needed to ensure the operational reliability of shoes. In the course of the study, graphical dependencies of the change in the force of pressure on the upper part of postoperative orthopedic shoes were used when bending the sole as a function of the inclination angle between the tangent to the foot of the footwear and the support area. The forces of load R on the upper end of the postoperative orthopedic footwear are determined when the forces of friction between the lateral surfaces of the freebie and the external lateral sides of the foot are neglected. In this case, the problem is reduced to the construction of the equilibrium equations of the plane system of forces. As the practice of using the Velcro fastener shows, with the increase of the tension of the supporting belt (with the loops), the force of detachment in the beginning increases to some maximum, and then, with increasing tension, the force of detachment decreases practically to zero. This circumstance may affect the reliability of the connection of the tops of orthopedic footwear. To ensure the strength of the fastener, it is necessary to choose the type of fastener, the width and the length of the active coupling area, the density of the hooks, which will ensure the reliability of the fastener in the shoes. The optimal design features and the greatest value of the pressure force on the upper part of postoperative footwear at bending of the sole observed at an angle γ=25o are obtained. This is due to the fact that the proposed material has a number of features, in particular the good density of hooks per cm 2 .

Design of cast-in headed and hooked fasteners

Cast-in fastenings for use in concrete are widely used in Australia. While design guidelines for headed fasteners are currently in place in Europe and the US, guidance on the design of hold-down bolts and hooked bolts (J- and L- bolts) is currently only available in the US. These types of fastenings to concrete are frequently used in safety-critical applications whereby failure may have serious consequences including risk to human life and significant economic consequences. In Australia, there are currently no design guidelines for these types of fastenings. Poor design procedures and lack of understanding of performance limitation of these fastenings have resulted in failures of base structures around the country. This paper presents design guidelines for cast-in fastenings to concrete including headed fasteners and hooked bolts that have been endorsed by the Australian Engineered Fasteners and Anchors Council (AEFAC). These design guidelines provide design engineers with greater confidence that the product will perform as required throughout its service life. Included in this paper are general design considerations to deliver best practice solutions.

Withdrawal Resistance and Failure Mode of Semi-Circular Wooden Composite with Different Fasteners

Wooden Composite is assembled with semi-circular waste wood by fastener, in order to provide local Indonesian affordable construction components potentially. Considering wooden composite, the withdrawal resistance affect the shear resistance ability under short-term lateral load, therefore withdrawal test is carried out in this study. The withdrawal test shows that steel nail and self-tapping screw work properly to attach each specimen when considering the assembly of wood composite. The observation results indicate different types of fasteners affect the test result significantly. For the fasteners connected with hardwood, the test result shows higher withdrawal resistance than softwood, both using self-tapping screw and steel nail. Based on the test results, there are 3 main failure modes that is concluded, which are fastener failure, material failure, and conditional failure. The test result of self–tapping screw also shows that this kind of fastener is able to withstand 3.5 times stronger than steel nail.

Testing of timber-to-timber screw-connections in hybrid configurations

This paper presents the results of an extensive experimental study on the short-term mechanical performance of timber screw connections comprising different types of fasteners (inserted at 45° and 90° to the grain) and different timber products (solid sawn timber, glued laminated timber, cross laminated timber and laminated veneer lumber) made from both softwood and hardwood species. Fifty-eight specimens laid out in fourteen arrangements were tested under quasi-static monotonic loading. The test configurations were meant to reproduce connections used in timber-to-timber hybrid composite structures for applications in both new constructions and retrofit interventions. Result comparisons regarding connection stiffness, strength, static ductility, residual strength and failure mode are presented and discussed. Additionally, the experimental data are used to check the extents of validity of existing analytical approaches (mainly developed for softwoods) to screw connections comprising hardwood elements. Practical aspects concerning screw insertion into hardwood elements are also addressed within the paper.

Идентификация закрепления трубопровода с использованием минимального количества собственных частот

Rassmatrivayutsya kolebaniya truboprovoda s zhidkost'yu. Raneye bylo pokazano, chto yesli zhidkost' ne techot po truboprovodu, to po vsem sobstvennym chastotam izgibnykh kolebaniy truboprovoda vid zakrepleniya truboprovoda opredelyayetsya odnoznachno s tochnost'yu do perestanovok zakrepleniy na yego kontsakh. Zadacha identifikatsii krayevykh usloviy reshalas' takzhe i po devyati sobstvennym chastotam. V nastoyashchey stat'ye kolichestvo sobstvennykh znacheniy, s pomoshch'yu kotorykh mozhno odnoznachno s tochnost'yu do perestanovok zakrepleniy na yego kontsakh vosstanovit' krayevyye usloviya, umen'sheno do pyati. Kolichestvo spektral'nykh dannykh udalos' umen'shit' za schot togo, chto yesli raneye reshalas' lineynaya sistema 9-ti uravneniy, to v nastoyashchey stat'ye reshayetsya sistema pyati nelineynykh uravneniy otnositel'no chetyrokh neizvestnykh koeffitsiyentov iz krayevykh usloviy, privedonnykh k kanonicheskoy forme. Predstavlen primer resheniya etoy obratnoy zadachi. Privedeny takzhe dva kontrprimera, v kotorykh pokazano, chto men'shego chisla sobstvennykh znacheniy dlya identifikatsii voobshche govorya nedostatochno. V pervom kontrprimere pokazano, chto chetyrokh nenulevykh sobstvennykh chastot yeshcho nedostatochno dlya identifikatsii vida zakrepleniya truboprovoda. Vo vtorom kontrprimere pokazano, chto v otdel'nykh sluchayakh neobkhodima informatsiya o tom, yavlyayetsya li nul' sobstvennym znacheniyem. Ещё 1 304 / 5 000 The vibrations of a liquid-filled pipeline are considered. It was previously shown that if the liquid does not flow through the pipeline, then the type of pipeline fastening is uniquely determined with an accuracy of up to permutations of fastenings at its ends by all natural frequencies of the pipeline bending vibrations. The problem of identifying the boundary conditions was also solved by nine natural frequencies. In this paper, the number of eigenvalues ​​with which it is possible to uniquely restore the boundary conditions with an accuracy of up to permutations of fastenings at its ends is reduced to five. The amount of spectral data was reduced due to the fact that if a linear system of 9 equations was previously solved, then in this paper a system of five nonlinear equations is solved for four unknown coefficients from the boundary conditions reduced to canonical form. An example of solving this inverse problem is presented. Two counterexamples are also given, which show that a smaller number of eigenvalues ​​is generally insufficient for identification. The first counterexample shows that four nonzero natural frequencies are still insufficient for identifying the type of pipeline fastening. The second counterexample shows that in some cases information about whether zero is an eigenvalue is needed.

Thermo-elastic-plastic Model for Numerical Simulation of Fasteners Destruction Under Gasodynamic Impulsive Pressure

Modern rocketry widely employs a method of gasodynamic impulse destruction of bondings which may occur at high variety of temperatures. To design fasteners correctly it is necessary to have the ability to calculate fastener’s destruction time at a given pressure. Numerical research is an expedient approach to this problem. A mathematical model of a high-speed deformation and failure in fastening elements of special rocket structures due to gasodynamic wave-impact impulse loading is developed. A technique for numerical analysis of the deformation of fasteners and failure duration is proposed. To perform such analysis a set of factors such as: static stress-strain state due to assembling; thermo-elastic deformation of fasteners due to environment temperature; high-speed dynamical elastic-plastic failure of fastening elements are taken into consideration. The failure model due to the plastic flow considers dynamical material properties. As a criterion of failure maximum plastic deformation is chosen. The technique is implemented for several types of fasteners. Numerical simulation using finite elements method is conducted. The results of the numerical research are well-correlated with experimental data.

Investigation of the frequencies of free oscillations of the above-ground main pipelines depending on the type of fastening

In this paper, we solve the problem of free bending vibrations of a thin-walled gas pipeline of large diameter laid above the ground on supports. The gas pipeline is considered as a cylindrical shell subject to the action of a stationary internal working pressure, the parameter of the longitudinal compressive force. The frequencies of free oscillations and the influence of parameters on the gas pipeline are compared with different versions of the supports.

Analytical modelling of a three-layer wall system of strengthening for large-panel slab buildings by means of bonded anchors

The goal of the article is to elaboration analytical models describing a new system of reinforcing three-layer walls of large-panel buildings with bonded anchors. The use of this type of fasteners that bond the façade texture layer to the structural slab is necessary due to the low durability of previously used suspension elements. Various bonded anchorage systems were considered. The new anchorage systems were designed as two-anchors systems (horizontal anchor and diagonal anchors) and three-anchors systems (horizontal anchor and two diagonal anchors). The inclinations of these anchors are in the range of 30°-60° in relation to the surface of the element. For the above types of reinforcements, analytical models have been developed that take into account the change of strength parameters of the resin and steel from which the anchors were made, the interaction of materials resin-steel and resin-concrete and the effect of the simultaneous action of pull-out and shearing forces. Moreover, was assumed the simultaneous destruction of fasteners two- and three-anchors. The elaborated analytical models will be used to determine the load-bearing capacity of the new connector system, which will allow the elaboration of guidelines for strengthening three-layer walls of largepanel slab buildings.

Effect of socket depth on failure type of fasteners

In this study, the effect of socket depth on failure types of fasteners were investigated in detail. Socket depth plays a vital role in structural integrity of fasteners particularly in weight reduction studies. Therefore, experimental studies were carried out by cold forged bolts having various socket depths. Fatigue and torque-tension tests were conducted to examine the critical socket depths under different loading types. Finite element analysis were also performed using SIMUFACT FORMING software. According to experimental and numerical investigations, it was shown that the socket depth has significant influence on failure mechanism of fasteners. Depending on the depth of sockets, the locations of the failures were shifted from the threads to the head of fasteners. The main reason for this type of shift was associated with the higher stress levels due to decrease in cross-sectional area of fastener heads. Consequently, it was shown that the critical socket depth is very important parameter in terms of structural integrity of fasteners and it has to be taken into account in the design stage of the every fasteners.