Shear Pin Research Articles

Dynamic load applied to shear pin and motion prediction of flexible hose

A flexible hose that is unwound along with fiber-optic cables from a mother ship helps prevent interference with the mother ship during the unwinding of the fiber-optic cable. Because the density of fiber-optic cables is close to the fluid density, if there is no flexible hose, the fiber-optic cable is more likely to interfere with the mother ship because of the motion of underwater vehicles or mother ships. Hence, it is necessary to prevent the interference of fiber-optic cables by using flexible hoses made of stainless steel. Flexible hoses unwound as an underwater vehicle moves are coupled to the vehicle by shear pins, and once all flexible hoses are unwound, the underwater vehicle continues to move forward as the pins fracture. Here, a dynamic load applied on the shear pin for connection in the early stages of the unwinding of the flexible hose is an important factor that controls the position, which should be accurately predicted, prior to the motion of the underwater vehicle. Further, it is essential that the shear pin of the connection part be designed to fracture under the selected load so that underwater vehicle can continue to move forward as the pin breaks. In this study, analysis results based on loading information measured in real experiments were compared and verified, and based on the findings, an analytical model that can predict loads applied on the shear pin was developed.

Fail-safe design and analysis for the guide vane of a hydro turbine

A design for the fail-safe mechanism of a guide vane in a Francis-type hydro turbine is proposed and analyzed. The mechanism that is based on a shear pin as a sacrificial component was designed to remain simple. Unlike the requirements of conventional designs, a shear pin must be able to withstand static and dynamic loads but must fail under a certain overload that could damage a guide vane. An accurate load determination and selection of the shear pin material were demonstrated. The static load for various opening angles of the guide vane were calculated using the computational fluid dynamics Fluent and finite element method Ansys programs. Furthermore, simulations for overload and dynamic load due to the waterhammer phenomenon were also conducted. The results of load calculations were used to select an appropriate shear pin material. Quasi-static shear tests were performed for two shear pins of aluminum alloy Al2024 subjected to different aging treatments (i.e. artificial and natural aging). The test results indicated that the Al2024 treated by natural aging is an appropriate material for a shear pin designed to function as a fail-safe mechanism for the guide vanes of a Francis-type hydro turbine.

The doxastic shear pin: delusions as errors of learning and memory

ABSTRACTWe reconsider delusions in terms of a “doxastic shear pin”, a mechanism that errs so as to prevent the destruction of the machine (brain) and permit continued function (in an attenuated capacity). Delusions may disable flexible (but energetically expensive) inference. With each recall, delusions may be reinforced further and rendered resistant to contradiction. We aim to respond to deficit accounts of delusions – that delusions are only a problem without any benefit – by considering delusion formation and maintenance in terms of predictive coding. We posit that brains conform to a simple computational principle: to minimize prediction error (the mismatch between prior top-down expectation and current bottom-up input) across hierarchies of brain regions and psychological representation. Recent data suggest that delusions may form in the absence of constraining top-down expectations. Then, once formed, they become new priors that motivate other beliefs, perceptions, and actions by providing strong (sometimes overriding) top-down expectation. We argue that delusions form when the shear-pin breaks, permitting continued engagement with an overwhelming world, and ongoing function in the face of paralyzing difficulty. This crucial role should not be ignored when we treat delusions: we need to consider how a person will function in the world without them..

Effect of shear pin arrangement in undercut slope model using pencil leads

Effect of shear pin arrangement in undercut slope model using pencil leads

Experimental study on shear behaviour of recycled concrete hollow block masonry

To study the shear behavior of recycled concrete block masonry with three rows of holes, the experiments were carried out on the type 240 specimens. The results showed that the shear damage mode of recycled concrete block masonry was brittle failure; the majority of destroy was double shear; the shear pin could greatly improve the shear strength; the influences of block type and intensity level on shear strength were small; the shear strength was mainly determined by the strength of mortar, and the shear strength increased with the increasing of the strength of mortar. The influence of difference of block material on the shear strength coefficient of variation was small, but the coefficient of variation was easily influenced by the water absorption, the construction quality. Considering the influence of the construction quality, the expressions on shear strength average value, standard value and design value were modified.

Application of recycled concrete aggregates as alternative granular infills in hollow segmental block systems

Geosynthetic Reinforced Segmental Retaining Walls (GR-SRWs) are developing as well recognized earth retaining structures for their manifold economic and technical advantages. It is a matter of great concern that still now a huge volume of natural coarse aggregate is used as filler in GR-SRWs, thus depleting natural resources and presenting a challenge for sustainable development. The main objective of this study is to examine the effect of recycled coarse aggregates (RCAs) used as alternative granular infills in hollow facing column. As granular infills, two types of recycled aggregates were used along with natural coarse aggregates (NCAs). Recycled aggregates were primarily selected based on the grading of the source waste concretes to investigate its effect on the frictional behavior of recycled aggregates used as infillers. Purely frictional capacity of I-Block infilled with recycled aggregates was compared to those infilled by fresh aggregates. To eliminate the effect of shear pins on interface shear capacity of I-Block system infilled with gravels, none were used in purely frictional shear. A series of direct shear tests was performed using a specially designed and fabricated direct shear apparatus to assess the frictional behavior of infilled blocks under different normal loading conditions. The tests were conducted following the exiting ASTM and National Concrete Masonry Association (NCMA) test protocols. The test results were outlined in the form of shear stress–displacement relationship to compare the effect of recycled aggregate against the fresh aggregate. Shear capacity envelopes were also plotted using Mohr–Coulomb failure criterion to find out the angle of friction for each case. Test results reveal that the angle of friction of the blocks infilled with the recycled aggregate is almost equal to those with the fresh aggregate. The results also show that compressive strength of the source waste concretes has a little or no effect on the frictional performance of recycled concrete aggregates used in facing units.

Analysis on Segment Floating in the Construction of Large-Diameter Crossing-River Shield Tunnel

Segment floating is a common problem met in the construction of large-diameter crossing-river shield tunnel. The factors affecting segment floating are discussed first and analyzed by numerical simulation, including the properties of grouting material, the speed of shield tunneling, grouting pressure difference, the tunnel longitudinal stiffness, frictional force between segment rings and weight of the supporting system. The simulation results indicate that segment floating will reduce by shortening slurry’s initial solidification time, slowing shielding speed, improving the tunnel longitudinal stiffness as well as increasing the frictional force between segment rings. And some measures are given such as applying new rapid-setting slurries, shear pins, rubber mats with high friction coefficient and pre-stressed bolts

Numerical simulation of the delay arming process of initiating explosive brakes

The delay arming process of initiating explosive (IE) brakes for fuse is complex and hard to be verified. A numerical simulation model of IE brakes was established based on the arbitrary Lagrange-Euler method. The model included the structure, the air filed, etc. The simulation boundary conditions were defined, including the contacts, blasting parameters of the explosive and the fluid-solid coupling interface. The simulation results show that the shear pin of the chosen IE can be cut off. When the piston needs to move 0.8 cm, the time set to the delay arming of the IE brakes model is about 40 μs. The maximum displacement of the piston is 1.17 cm. The model provides basis for parameters design and further improvement of IE brakes.

Feasibility Analysis of Reverse Sealed Testing String in HPHT Wells

To solve problems met in an offshore High-Pressure High-Temperature (HPHT) well testing, a new technology is put forward—placing seal bore extension above permanent packer, and the upper landing tools being connected with seal bore extension through shear pins. This method gives a reverse position of seal bore extension compared with conventional way in which seal bore extension is below permanent packer. So, the feasibility must be considered. Two technological procedures, testing before cutting pins and testing after cutting pins, are discussed, and the highlight is on axial force and deformation of testing string at crucial moments. Results indicate that this new technology is feasible. Of the two technological procedures, axial force is the key factor when testing before cutting pins and axial deformation is the key factor when testing after cutting pins. Conclusions have been used in an offshore HPHT well testing design.

Development of the ITER IOIS assembly tool and mock-up

The ITER toroidal field coils (TFCs) are connected by 3 different connecting structures as follows; Outer Intercoil Structure (OIS), Inner Intercoil Structure (IIS), Intermediate Outer Intercoil Structure (IOIS). In assessing the assembly, requirements and environmental conditions of each Intercoil structure, the IOIS and IIS assembly were thought to be the most challenging compared to the OIS assembly due to the very limited assembly space available and the strict requirements requested by IO, especially the IOIS assembly, which has particularly difficult installation requirements including complicated shear pin assemblies. A conceptual and preliminary design has been developed by the Korean domestic agency (KODA) for the sub assembly and final assembly phase; the tool includes the ability to control both IOIS plates simultaneously. For design verification of the IOIS assembly tool mentioned above, structural analysis has been carried out considering seismic event. Also, a half sized mock-up has been fabricated and tested according to assembly procedures. In this paper, a description of tool design and the results of analysis and mock-test will be introduced.

보호 튜브의 풀림 거동 및 하중 예측

심해 군사 작전에서 유도체의 타격 성능 향상은 모함과 유도체가 광 케이블을 통하여 안정적인 통신을 유지함으로써 가능하다. 이 때 광 케이블은 엉킴 및 절단과 같은 풀림 불량을 방지하기 위해 보호 튜브에 의해 보호된다. 또한 보호 튜브는 전단 핀에 의해 유도체와 연결되며, 전단 핀의 파손에 의해 유도체는 보호 튜브와 분리된다. 따라서 본 연구에서는 유도체 및 보호 튜브를 모델링하고, 유도체의 운동에 따른 보호 튜브의 풀림 거동을 분석하며 전단 핀에 작용하는 동적 하중을 예측한다. 유도체와 보호 튜브는 질점으로 구성하며, 일정 길이 구속으로 연결한다. 전단 핀에 작용하는 하중은 실험 결과와 비교 검증하며, 이를 바탕으로 보호 튜브의 거동을 예측한다.

Reducing production loss by prolonging service life of rolling mill shear pin with ultrasonic nanocrystal surface modification technology

Premature failure at the shear pin of stainless hot rolling mill caused by increasing productivity and fluctuation of roll torque raises significant downtime cost. To reduce downtime cost, UNSM (Ultrasonic Nanocrystal Surface Modification) treatment is applied to the neck groove of shear pin as the alternative to existing solutions. This treatment prevents premature failure, increases service life and reduces the number of replacements. Proper process variables of UNSM technology which give the strongest fatigue strength are determined by comparing with S-N curve of rotary bending test result. Surface roughness, hardness and compressive residual stress on three kinds of test specimens are analyzed together with SEM analysis of fracture surface. Real shear pins are produced by the property of highest fatigue strength and installed to the hot mill stand for validation. They come to pass as twice as the original operation cycle.

Enhanced Performance of Steel-Aluminium Cast Nodes through Cold Metal Transfer

At present, enhancement of hybrid metal joints for tensile pull-out load through overlap surfaces with a macro-scale roughness is one scope of research. The macro-scale roughness is established through the modified arc-welding process, called “cold metal transfer pin” (CMT-pin), which enables repetitive manufacturing of arrays of metal reinforcements (pins) on parent metal surfaces.Hybrid metal joints between parent steel sleeves and cast aluminium alloy have been investigated. Joint surfaces of parent steel sleeves, which have cylindrical cross-sections, are modified by cylinder and ballhead pins. Cast metal joints were tested under uniaxial tensile loading. At the same time, their load transfer behaviour was determined. Results of tensile tests of hybrid metal joints with different kinds of pins, as well as with different amounts of pins are presented. Comparisons with reference joints without pins or with steel sleeves containing a harmonious triangular polygon cross-section ("P3G") and endings with an enlarged diameter are carried out.The results show an enhanced load transfer performance in the case of hybrid metal joints with pins, as well as enhanced performance measures compared to reference joints. It is also shown that the pin quantity has a major impact on the ultimate joint strength and the irreversible energy absorption density. The use of a certain quantity of pins leads to a change of the failure shape of the joints, which includes steel sleeve pull-out and pin shear to rupture of the cast aluminium.

Numerical Simulation and Structural Model Shaking Table Test for Container Crane Equipped with Seismic-isolated Device

Modern large-gauge container cranes are often damaged or even collapse in earthquake. By researching into the damage forms of container cranes in Hyogo-ken Nanbu Earthquake, it is concluded that horizontal seismic force perpendicular to the rail is the main reason for the damage. Based on the theory of seismic isolation, a new type of seismic-isolated device, composed of dual eccentric rotary bearing, Belleville spring, oil damper and shear pin, was designed for container crane. A 3D-FEM system model was established to numerically analyze acceleration response, inspired by Iran seismic wave, etc., with the method of Newmark-. Furthermore, a seismic miniature model was designed according to similarity principle with dimensional analysis method. Then, taking acceleration and displacement as similar indicators, a shaking table test was carried out, and inspired by the same seismic wave. The results of numerical simulation and model test prove with each other, that the seismic-isolated device is a reasonable design and the effect of seismic isolation is significant.

Computer programming for prediction of soil bulk density effect on trencher design parameters

A computer program was developed in C++ language to predict the effect of soil bulk density on draft force on bottoms, share thickness, stresses distribution and maximum deflection on standards, bending stresses distribution on side plates, diameter of shear pins, and tensile stress on hitch bar. ?It was found that, as soil bulk density increased, stresses distribution and maximum deflection on standards, bending stresses distribution on side plates, diameter of shear pins, and tensile stress on hitch bar increased. ?The diameter of shear pin should be larger to meet wide range of soil density. Keywords: trencher, computer program, soil, draft force, bulk density, prediction DOI: 10.3965/j.issn.1934-6344.2011.04.042-049 ? Citation: Mohamed Hassan Dahab, Moayed Mohamed balal. ?Computer programming for prediction of soil bulk density effect on trencher design parameters. ?Int J Agric & Biol Eng, 2011; 4(4): 42

Study on Fracture Test of Rocket Shear Pin

In order to study effects of geometric parameters in fracture test, this paper used 3D modeling software Solidworks and finite element analysis software Deform to simulate the fracture process of rocket shear pin and study the effects on shear test while various geometric parameters change in the assembly of fixtures and shear pins. According the results we improved the fixtures of shear test. The new fixtures were used in the rocket shear pin fracture test.

Multi-level analysis of low-cost Z-pinned composite joints: Part 2: Joint behaviour

In the framework of the E-U program ALCAS (Advanced Low-Cost Aircraft Structure), a new Z-pinning technique was developed by EADS Innovation Works. This technology was used to manufacture low-cost Z-pinned junction demonstrators (L and T shaped specimens) typical of aeronautical structures. In order to understand load transfer mechanisms in this kind of assembly, a multi-level analysis was performed. In the first part of this study, tension and shear pin behaviour was investigated as well as pin pull-out from neat resin or laminate. An analytical model was proposed to predict the maximum load capability of a single pin for an insertion depth of less than 8 mm which correspond to the usual technology. Now, in this second part, we demonstrate that the behaviour of the junction under pull-out, shear and unfolding is globally homothetic to the mechanical behaviour of a pin. This study provides the basis for a pre-sizing methodology for Z-pinned junctions under complex loading.

Multi-level analysis of low-cost Z-pinned composite joints: Part 1: Single Z-pin behaviour

In the framework of the EU program ALCAS (advanced low-cost aircraft structure), a new Z-pinning technique was developed by EADS Innovation Works. It was used to manufacture low-cost Z-pinned junction demonstrators (L and T shaped specimens) typical of aeronautical structures. In order to understand load transfer mechanisms in this kind of assembly, a multi-level analysis was performed. Firstly, tension and shear pin behaviour was investigated as well as pin pull-out from net resin. It was demonstrated that the mechanical transfer is mainly through bonding, even when the pins are twisted. Secondly, an analytical model was proposed which predicts the maximum load capacity of a single pin. Finally this study provides the basis for a design methodology to compute ultimate loads of Z-pinned junctions under complex loading.

Development of General Embedded Intelligent Monitoring System for Tower Crane

Development of General Embedded Intelligent Monitoring System for Tower Crane

Failure analysis of shear pins in wind turbine generator

This paper examines the failure of shear pins that connect gearbox and generator in a wind turbine generator. Chemical and micro-structural together with hardness measurements have been performed to check any deviation in the material specification. The failure mechanism is analyzed by both visual and Scanning Electron Microscope (SEM) inspection on the fractured surface. Finite Element Analysis (FEA) of shear pin is carried out to determine the root cause for its failure. The neck diameter of shear pin is optimized for the safe operation of the wind turbine. It is inferred from the observations based on fractography study on the fractured surface of the shear pins that the misalignment between the driving and the driven elements in the wind turbine leads to low cyclic fatigue growth.