Dowel Pins Research Articles

Study on Joint Model Simplification for Finite Element Analysis of Bamboo/Wood-Oriented Strand Board Furniture.

Board furniture's performance and scientific design are making it popular. Research on simplifying furniture joints reduces design cycles and costs and improves structural safety. In this article, using a cantilever beam to calculate deflection theoretically simplifies the L-shaped component model and yields a joint elastic modulus formula. Finite element analysis (FEA) confirms the effectiveness of this simplified model by comparing its results with experimental data. In simplified components, the joint elastic modulus increases with length (l2) and stabilizes at l2/b ≥ 6 (b is the board's thickness). The variation pattern of the joint elastic modulus equals that of the stiffness, proving its usefulness in assessing component deformation resistance. Furthermore, the component strength and stiffness are also affected by the screw spacing and connector type. In particular, the connectors type affects bamboo-oriented strand board (BOSB) component performance more than wood-oriented strand board (WOSB). Compared to WOSB, BOSB components have superior strength and stiffness and are more stable. The recommended screw spacing for L-shaped components is 48 mm. BOSB components fixed with two-in-one and metal nuts utilizing threads embedded in the board have better strength and stiffness, while for WOSB components, nylon nuts, and wooden dowel pins are more appropriate for securing.

Measurement Approach for the Pose of Flanges in Cabin Assemblies through Distributed Vision.

The relative rotation angle between two cabins should be automatically and precisely obtained during automated assembly processes for spacecraft and aircraft. This paper introduces a method to solve this problem based on distributed vision, where two groups of cameras are employed to take images of mating features, such as dowel pins and holes, in oblique directions. Then, the relative rotation between the mating flanges of two cabins is calculated. The key point is the registration of the distributed cameras; thus, a simple and practical registration process is designed. It is assumed that there are rigid and scaling transformations among the world coordinate systems (WCS) of each camera. Therefore, the rigid-correct and scaling-correct matrices are adopted to register the cameras. An auxiliary registration device with known features is designed and moved in the cameras' field of view (FOV) to obtain the matrix parameters so that each camera acquires traces of every feature. The parameters can be solved using a genetic algorithm based on the known geometric relationships between the trajectories on the registration devices. This paper designs a prototype to verify the method. The precision reaches 0.02° in the measuring space of 340 mm.

Determination of Needle Penetration Force and Pump Pressure for the Development of an Automated Trunk Injection System for HLB-Affected Citrus Trees

Highlights An equation was developed for estimating the needle penetration force required for trunk injection. A method to determine the required pump pressure for citrus tree trunk injection was developed. This information can be used for the development of a drill-free, pressurized, automated trunk injection system. Abstract. Targeted precisemanagement of intravascular diseases such as citrus Huanglongbing (HLB) involves the application of therapeutics via trunk injection.Although trunk injection has proven more effective than foliar spray and soil drenching, multiple studies have highlighted limitations for large-scale commercial tree crop applications because of the manual process involved, emphasizing the need for an automated injection system.The design of a trunk injection mechanism to efficiently dispense aqueous therapeutic materials to the trunk of HLB-affected citrus trees requires the characterization of the hydraulic properties of the trunk and the determination of the penetration force of a dispensing needle. This study developed an equation for estimating penetration force at maximum depth based on the needle diameter, depth of penetration, and specific gravity of the wood tissue, and presents a method for estimating injection pump pressure. Trunk hydraulic conductance was measured using a hydraulic conductance flow meter, and needle insertion and removal force were measured using a force gauge in an Instron universal testing machine. The average maximum force was 2517, 3739, and 5387 N for dowel pins 4.76, 6.35, and 7.93 mm in diameter at a 12 mm penetration depth. Average specific conductivity was 2.45, 0.34, and 0.15 kgs-1m-1MPa-1for trunk segments 0–12.7, 12.7–26.7, and 26.7–40.6 cm above the ground, with a corresponding estimated pump pressure of 0.14, 0.99, and 2.31 MPa, respectively. Keywords: Automated trunk injection, Drill-free, Huanglongbing, Plant diseases.

FEM Analysis of 3D Timber Connections Subjected to Fire: The Effect of Using Different Densities of Wood Combined with Steel

This work aims to present a study approach for double-shear connections of wood under fire with dowel pins and plates in steel material, using different types of glulam. The simplified Eurocode equations for ambient temperature were used to determine the dimensions and the number of dowel pins that each studied connection needs in order to resist an applied tensile load. Following this methodology, the finite element method was used to assess the thermal analysis of the studied connections under fire. The study aims to increase the information on these connections, where the wood material represents a complicated behavior in fire circumstances, with the addition of the steel material. The heat conducted by the dowel pin inside the connection, and the steel plate and its effect on the wood were analyzed. According to the results, it can be assumed that the temperature evolution is due to the geometry of the connection, the dowel pin or plate position, and the glulam density. Inside the wood element, the temperature remains lower, and externally a charred depth is developed when the target temperature of 300 °C is reached, and, in the vicinity of the dowel pin or the steel plate, a burned wood depth is indirectly formed. The rate of the charred layer is not constant throughout the entire fire exposure. Steel-to-timber connections with an internal steel plate with high glulam density have greater fire resistance due to the lower temperatures obtained.

Manufacturing of non-threaded fasteners: an analysis of non-conformities during manufacturing process and abatement

This article projects the systematic approach for reducing the rejection during manufacturing of non-threaded fasteners i.e., Dowel Pin by Basic Quality tools. It includes the systematic study of the manufacturing process of non-threaded fastener and its inspection at different stages of manufacturing. The analysis of Dowel Pin’s manufacturing process has been taken place at industry A and modification in the process, drawing and work holding device of the Machine Tool have been done. After implementation of the modifications in the manufacturing process, the desired results have been achieved. The improvement has been visualized in the results.

Shaking table test for dimension stone cladding with dowel pin connection

Under earthquake loads, economic loss and threatening human casualties can occur owing to fallouts of exterior cladding stones in buildings. In this study, a shaking table test was performed to investigate the seismic capacity and demand of stone cladding with pin connections. Two reinforced concrete structures attached to dowel-pinned stone panels were tested under ground motion to simulate actual earthquake conditions. A total of 19 combinations of stone panels were used to address the major parameters for the construction of dimension stone claddings in practice. The test results showed that in most of the specimens, pull-out failure of the pin connection occurred prior to the stone breakout failure, resulting in stone fallout. The seismic demand for stone panels without an insulator was significantly less than the seismic capacity, showing a capacity-to-demand ratio of 4.00–12.60. However, the capacity-to-demand ratio was 0.37–2.66 in the case of stone panel details with an insulator but without a supporter, indicating that special care is necessary for those details. Based on the test results, design and specification recommendations were proposed for stone panels with dowel pin connections.

Application of Alternative Methodology to Select the Optimum Design of TCU Carrier Using FEA

<div class="section abstract"><div class="htmlview paragraph">The transmission control unit is used in automobile domain, to control the automatic transmissions. TCU is associated with mechanical parts like Housing, Carrier, Hydraulic Plate etc. In this case, TCU carrier is mounted on hydraulic plate using a dowel pin to locate it accurately. During servicing of the TCU, Carrier with dowel pin is subjected to high displacement which leads to huge plastic deformation & failure of the carrier. A study was required using Finite Element Analysis for a series of designs to evaluate their structural stability and to recommend the best possible design. ANSYS tool is used for the simulation. During this study, when conventional method of reckoning stresses and strains as a criterion of comparison was adopted, it involved a tedious process & required many numbers of iterations. Despite plenty of iterations, it may not be possible to conclude the exact force at which the carrier fails or the max displacement it can withstand. The other reason to look for an alternative method is, the development team expectations about the structural stability of the carrier considering operating conditions is contradicting with the strains observed with conventional method. So, there was a need to develop alternative method to evaluate the carrier strength. Hence, stiffness criterion is obtained as a solution. Series of designs are compared based on stiffness & deformation criterion for loads ranging from operating load of 3 mm to maximum displacement load of 6 mm. The simulation results through this stiffness method obtained are also validated with testing results and accuracy of results is observed. This study using stiffness method helped us in selection of best possible carrier design suitable for maximum displacement load without any failure. Cost of testing for around 6 designs is reduced by using FEA and optimum design is also obtained.</div></div>

DOWEL PIN - SNAP FIT TECHNIQUE: A NOVEL SPLIT CAST TECHNIQUE

Complete denture construction comes with a lot challenges both during the clinical and laboratory steps. Lab remounting is one of those steps it is done to mount the master cast back in position after acrylisation of the complete denture to undergo selective grinding. But the conventional methods used for this technique have not been good enough to hold the master cast in place in a stable manner. The novel technique introduced in this article uses dowel pins for remounting, and it provides a more stable, reliable and snug fit technique without making the technique any more complicated.

Monitoring multivariate coefficient of variation with individual observations

AbstractMonitoring the multivariate coefficient of variation (MCV) is conducted when the multivariate process variation changes proportionally with the mean vector because under this situation the traditional multivariate charts for the mean and variance cannot work correctly. All existing MCV charts in the literature are implemented based on sample MCVs computed from samples of size larger than unity each. However, there are situations when forming samples (of ) is not feasible. To address the aforementioned limitation of existing MCV charts, in this paper, an EWMA chart based on individual observations for monitoring the MCV is developed. Numerical studies based on Monte Carlo simulations are conducted to investigate the run length properties of the proposed chart in detecting either increases or decreases in the MCV, for two and three quality characteristics and various parameter values. A real bivariate dataset on the diameter and length of dowel pins is adopted to illustrate the implementation of the proposed chart.

Evaluation of slip behaviour of self-locking modular steel connection

Modular steel building (MSB) is an exceptional substitute for traditional on-site steel construction. Bolt hole tolerance is provided in inter-modular connections (IMC) to allow positioning of modules which causes a higher initial slip of bolted connection. This study proposes a new connection with a four-stage assembly procedure that omits the need for excess hole tolerance in bolted connections and provides higher initial stiffness. The performance of this proposed connection is evaluated using finite element analysis, which has been validated against the existing experimental data from the literature. An analytical study is conducted on two variants of the proposed connection, the first variant with bolts and the second variant with dowel pins, to evaluate the shear force-slip behaviour. The force-displacement curve of the proposed connection is compared with existing models of bolted connections. Results show that the connections with pretension force applied on bolts had good agreement with the traditional four-stage model for bolted connection. Equations provided by established design codes can predict the initial stiffness in IMCs.

Evaluation of split-cast techniques for remounting casts on adental articulator: A survey and an in vitro study.

This study aimed to investigate the difference between senior dental students and prosthodontic faculty members regarding their opinions, attitudes and adoption of six split-cast techniques for remounting complete dentures. The accuracy of each technique for measurements of the vertical and the anteroposterior dimensions was assessed. Six split-cast techniques to remove the casts were compared. A total of 115 participants removed a set of casts on six different articulators, and a questionnaire survey was administered. A digital Vernier caliper was used to measure the linear dimensional changes between the laterally pindexed references on each cast. The data were statistically analysed at α= 0.05. There were significant differences between senior dental students and prosthodontic faculty members in their responses regarding adoption of daily practice and techniques requiring more skill (p=.001). To adopt a specific technique in daily practice, most students and faculty members chose long round die pins (36.4%) and central groove indexing (CGI; 40.7%), respectively. For techniques requiring more skills, most students and faculty members chose long rectangular die pins (30.7%) and short round dowel pins (33.3%), respectively. Dental students preferred ShRP, whilst faculty members preferred LReP. All participants considered CGI to be the easiest amongst the techniques. For comparison with baseline measurements, both senior dental students and prosthodontic faculty members considered side notch indexing and double dowel pins to be the most accurate techniques for vertical measurements, and CGI for anteroposterior measurements.

Evaluation of the Treatment of Feline Metacarpal and Metatarsal Fractures Using Dowel Pinning Technique

This study is aimed to evaluate the postoperative results of the operations performed with the dowel pin technique in metacarpal (Mc) and metatarsal (Mt) fractures of cats, clinically and radiologically. A retrospective evaluation was carried out for 10 cats with Mc and Mt fractures by performing clinical and radiographic examinations for an average of 4.5 months after surgery using the dowel pin technique. In the evaluation, the number of fractures, fracture type and localization, fracture healing, and postoperative complications resulting from clinical and radiographic results, postoperative observations, and the animal owners' observations in the postoperative process were considered. Questionnaires made to animal owners were evaluated. Clinical and radiographic evaluation of the cats included in the study was performed. After the 12th week of the study, there was no information from two cats. Nine of the clients (90%) reported no significant change in their cat's walking after treatment. One client reported that after 4 weeks postoperatively, the cat kept its extremity at rest and suffered from persistent lameness at a minimal level. In conclusion, despite the limited case series of the study, it is seen that the dowel pin technique is a simple, economic, effective, and reliable method for the surgical healing of Mc and Mt bone fractures.

Micromachining and Characterisation of Folded Waveguide Structure at 0.22THz

The demand of high-speed wireless communication has increased, which need the data rate to be in the order of Terabyte per second (Tbps) in the near future. Terahertz (THz) band communication is a key wireless communication technology to satisfy this future demand. This would also reduce the spectrum scarcity and capacity limitation of current wireless systems. Microfabricated Folded Waveguide TWTs are the potential compact sources of wide band and high-power terahertz radiation. This study primarily focuses on machining technology for THz waveguide components requiring ultra-high precision micromachining. Rectangular waveguides, especially Folded Waveguides (FW), are even more difficult to manufacture using conventional machining techniques due to their small size and very tight tolerances. The criticalities in micromachining of FW for 0.22 THz have been addressed in this article. Half hard free cutting Brass IS 319-H2 was used as a work material due to its electrical and mechanical properties. Waveguide size of 0.852 × 0.12 mm was machined within ± 3–5 μm linear tolerances, surface roughness in the order of 45 nm Ra, and flatness less than half of wavelength (< λ/2). The split top and bottom blocks of the folded waveguide were aligned by dowel pins which matched within a tolerance of ± 5 μm. The perpendicularity and parallelism were maintained within 5 μm tolerance. This work explored and established the application of micromilling as reasonably suitable for the THz waveguides followed by ultrasonic cleaning as deburring. It also investigated the measured folded waveguide losses which were close to simulated values.

Direct shear test and cyclic loading test for seismic capacity of dimension stone panel cladding with dowel pin connection

In this study, direct shear test and cyclic loading test were performed to investigate the seismic capacity of dimension stone cladding with pin connections. A total of 60 dowel pin connection specimens were tested under direct shear, and 12 panel specimens were tested under quasi-static cyclic lateral loading in the out-of-plane direction of the panel. The major test parameters were type of stone, drilled hole diameter for dowel pin connection, thickness of stone panel, and type of dowel pin. In the direct shear test of dowel pin connection, the tested peak strengths agreed with the results predicted by analogy to the breakout strength in ACI 318. However, the results of cyclic loading test showed that the shear strength of the dowel pin connector was decreased, due to the effect of flexural action under cyclic loading of the panel. On the basis of the direct shear test results and panel test, a stone breakout strength was proposed considering the effect of flexural moment. On the other hand, the flexural strength of the panel was accurately predicted by the cracking moment based on the fracture modulus of stone.

Load Bearing Capacity of Precast Concrete Slab–Wall Connection

Precast concrete slabs and their supporting walls are connected using dowel pins, anchoring loop bars, and cast-in-situ concrete. The design resistance of such connections can be calculated using multiple different methods. The design load bearing capacity can vary depending on the method used and assumptions made during calculation, making it difficult to determine, which methods are reliable and should be preferred. The study ordered by construction company JSC “UPB” discusses two design methods proposed by Eurocode 2 and fib Bulletin 43. A semi full-scale loading tests of concrete walls and slab specimens are carried out. The results show that the design methods considering only the contribution of steel dowel pins, underestimates the actual capacity of the connection by 2 to 4 times. On the other hand, the methods, considering both the contribution of the dowels and the friction between concrete interfaces, correspond well with the experimental results.

Comparing Standardized and Manufacturers’ Interfaces for Waveguides Used at Submillimeter Wavelengths

This article presents a comparison between the specified dimensions given in document standards (IEEE Std 1785.2-2016) and the measured dimensions for interfaces used with rectangular metallic waveguides at submillimeter wavelengths. The standardized dimensions of these waveguide interfaces are compared with several waveguides in the WM-380 band (500–750 GHz) manufactured by two different companies. The measured electrical performance (in terms of reflection coefficient) for these waveguide interfaces is also compared with values given in documentary standards. The article shows that although the manufactured waveguides do not strictly adhere to the dimensions given in the standard, very good electrical performance is still achievable by using slightly different dimensions for the manufactured waveguide interfaces. The use of additional alignment dowel pins (as specified in the IEEE standard) further improves the electrical performance of these interfaces.

Load-bearing capacity testing of dowel pin anchorage in granite cladding

To investigate the load-bearing capacity of a dowel pin anchorage, monotonic tests were performed. Results show that the ideal failure mode of the dowel pin cladding system is plastic shear or shear and bending deformation of the steel pin prior to rupture of the dowel. It was also found that the maximum load-bearing capacity of a 5 mm pin with sleeve is 30% higher than that without a sleeve, while that of the 8 mm pin system with sleeve is only 6% higher than that without sleeve, which means that the existence of the sleeve contributes to the load-bearing capacity to some extent. Cladding with 5 mm steel pins has two failure stages, namely, pin yielding and panel rupture, which allow the steel pins to deform plastically and dissipate energy before total failure of the anchorage. Cladding with 8 mm pins has only one failure stage, namely, sudden rupture of the panel without any prior warning signs. The rupture surface of the panel has an angle of 24° to 29° on the side surface, and 27° to 33° on the top surface. More comprehensive experimental and analytical studies are needed to develop a reliable calculation method of the failure load.

NUMERICAL MODELING AND FULL-SCALE EXPERIMENTS OF GLUED WOODEN STRUCTURES JOINT DESTRUCTION ON CARBON-FIBER DOWEL PINS

This paper presents the results of numerical modeling and full-scale experiments of the failure process of a glued laminated timber beam with rigid joint in the middle. All the connecting parts are made of carbon fiber. The structural analysis is done with the finite element method (ANSYS software). The nonlinear problem was solved. The contact interaction of the structural elements in the process of deformation and fracture, as well as orthotropy of the wood, the transversely isotropic properties of the plates, and the real diagrams of the deformation of carbon fiber dowel pins were taken into account. The influence of the structural parameters of the joint on the position of the most loaded dowel pin in the joint and the bearing capacity of the general structure are investigated. To verify the structural analysis results, field tests were carried out before destruction by a stepwise increasing load on a personally designed stand. The destruction of the structure occurred according to the forecast of the numerical model as a result of the mutual slip of the glued wood layers and the destruction of the polymer matrix of the glued dowel pins with the beginning of the formation of plastic joints and the formation of cracks in the wood at the junction.

Experimental investigation of the breaking load of a dowel-pinned connection in granite cladding

A dowel-pinned anchorage in granite cladding has been widely used in modern granite cladding systems. However, current studies on the breaking loads of dowel-pinned connections are limited, and the damage behavior is not yet clear as a result of insufficient experimental studies. In accordance with current code provisions, monotonic static loading tests were carried out to investigate the breaking load and failure modes of a dowel-pinned cladding connection. The specimens were 200 × 200 × 30 mm granite panel with holes drilled in the middle of each side for steel pins with three different diameters, that is, 5 mm, 6 mm, and 7 mm. The results show that when using the 5 mm steel dowel pin, the steel pin yielded with a certain plastic deformation prior to the V-shape fracture of the granite near the dowel hole. When using the 7 mm and 8 mm steel pins, the U-shape fracture of the granite panel occurred first. Then only slight bending deformations of the steel pins were observed. The experimental breaking load was compared to the computational results following the formula recommended in the literature. A conceptual loading skeleton curve was developed to illustrate the damage progress of the connection. It revealed the load redistribution mechanism in the connection in a representative manner with which the calculated stress in the steel pin is corresponded to the experimental breaking load. This study is helpful for understanding the damage behavior of the novel connection in stone claddings.

Shaking table tests of granite cladding with dowel pin connection

Shaking table tests are conducted to investigate the seismic performance of new steel dowel-pinned granite claddings with two support systems. Standard and modified body anchors are used for installing the granite cladding system on opposite sides of a strong reinforced concrete tube fixed to the shaking table. One recorded ground motion (El Centro) and two artificial motions are applied as the input motions. The whole cladding system remained intact and almost no visible damage was observed for El Centro. However, the seismic responses of the cladding system under the effect of the artificial motions were larger. The dynamic response of the standard body anchors was larger than that of the modified ones. The maximum component amplification factors are larger than those specified in current code provisions. It is noted that the load bearing capacity of the body anchors determines the seismic performance of the global granite cladding system. Therefore, additional measures should be taken to guarantee the required seismic capacity of the stone cladding system by using the proposed steel dowel pin connections.