Plastic Bolt Research Articles

Adjustable and Magnetic Resonance Imaging Conditional Implantation of a Licox Brain Tissue Oxygenation Probe in Neurosurgery: Technical Note

Continuous bedside brain tissue oxygen monitoring is an essential part of managing comatose patients with acute brain injury. Maintenance of adequate brain oxygenation has been established as an important goal in neurocritical care to prevent patients from secondary ischemia. As patients with subarachnoid hemorrhage and traumatic brain injury often require early magnetic resonance imaging, conventionally implanted metal bolts are disadvantageous due to massive artifacts. We hereby report a novel technique of magnetic resonance imaging conditional bedside implantation of a brain tissue oxygenation probe. We performed bedside implantation of a Licox brain tissue oxygenation probe with a peripheral venous cannula that is placed through a plastic bolt placed on a burr hole. Bedside implantation of a Licox brain tissue oxygenation probe was successfully performed in a novel fashion. This article describes the feasibility of a novel technique of bedside implantation of a Licox brain tissue oxygenation probe, resulting in a length-adjustable insertion and rigid fixation without metal artifacts in early magnetic resonance imaging.

Asymmetric Friction Connection (AFC) design for seismic energy dissipation

Asymmetric Friction Connections (AFCs) are used to dissipate seismic energy via friction. AFC strength is affected by moment–axial force–shear force (MPV) interaction. Current MPV models do not consider the increase in bolt tension due to bolt rotation as bolts are assumed to yield axially during AFC assembly. A MPV model is proposed for AFCs considering the increase in bolt axial tension due to bolt rotation, and elastic or elasto – plastic bolt axial behaviour. A parametric study is presented describing the relative impact and effects of bolt rotation, bolt thread, ultimate strength, friction coefficient at the sliding interfaces, and bolt axial relationship. The predicted AFC strength is validated against experimental data from 60 tests of AFCs with Grade 8.8 bolts and Bisalloy 400 shims, and 18 experimental tests with Grade 8.8 bolts and Bisalloy 500 shims. The proposed MPV model considering elasto-plastic bolt axial behaviour better matches the experimental data with average absolute errors of 0–18% for AFCs with M16, M20 and M24 bolts, and of 55–79% for AFCs with M30 bolts. Finally, the model validation indicates the current in practice overstrength and understrength factors of 1.40 and 0.70 can be used with this particular model in design to consider: (i) the variability of the sliding strength due to the bolt fabrication and assembly issues; and (ii) the degradation of sliding surfaces.

Application of FRP Bolts in Monitoring the Internal Force of the Rocks Surrounding a Mine-Shield Tunnel.

Monitoring the internal force of the rocks surrounding a mine-shield tunnel for the initial support of a mine-shield tunnel, in complex geological and hydrological environments, requires bolts with specific features such as high tensile strength, low shear strength, good insulation and resistance to corrosion. As such, internal force monitoring has become an important issue in safety monitoring for such tunneling projects. In this paper, the adaptability of a mine-shield tunnel project in a corrosive environment is investigated. A fiberglass reinforced plastic (FRP) bolt with high tensile strength, low shear strength, resistance to fatigue, non-conductivity and resistance to corrosion is used as a probe in tandem with an anchor-head dynamometer to monitor the internal force of the rocks surrounding a mine-shield tunnel for initial support. Additionally, solar energy collection technology is introduced to create a remote monitoring system. Using a 2.5 km long railway tunnel located in the northeast of the Pearl River Delta of China as a case study, the present study shows that, compared with a conventional steel bolt, the FRP bolt has advantages, such as avoidance of the risks associated with the shield machine, insulation and resistance to corrosion. As a probe, the response of the FRP bolt to events such as a blasting vibration and a construction disturbance that results in internal changes in the surrounding rock demonstrates a clear pattern that is appropriate for monitoring the internal force of the rocks surrounding a mine-shield tunnel in a corrosive environment. FRP bolt-based monitoring not only provides new technological support for controlling the risk involved in the initial support of a mine-shield tunnel but can also be widely deployed in projects with special requirements for disassembly, conductivity and corrosion.

Mechanical behaviour of fully grouted GFRP rock bolts under the joint action of pre-tension load and blast dynamic load

In mining operations, the stability of excavations is critical to ensure the safety of production. Rock bolt support is the most effective and economical method commonly used to improve ground stability. The glass-fiber-reinforced plastic (GFRP) bolt has been developed and is becoming widely used because of its corrosion resistant character and its high tensile strength. However GFRP bolts are more susceptible to damage by blast loads and therefore it is important to understand the mechanical behaviour of GFRP bolts under dynamic loads so the support system can be better designed. In this paper we propose a new approach to describe the mechanical behaviour of fully grouted GFRP rock bolts under the combination of pre-stressed static load and blast dynamic load using the Kelvin’s solution. The method was applied to a case study and it was found that large axial and shear stresses of fully grouted GFRP rock bolts are mainly distributed in a small region near the bolt collar. It was further demonstrated that the strength of blasting, the distance between the rock bolt and the blasting point and the Young’s modulus of the rock mass and the bolt material are the most important factors having significant influences on the mechanical behaviour of GFRP bolts. For the cases examined where the bolt is within the range of 15 m from the blasting point, the influence of blast load on the axial and shear stresses of the rock bolt is significant and the dynamic load is the main factor causing the support damage. The proposed model provides a method to quantitatively evaluate the effect of blasting on the mechanical behavior of GFRP rock bolts so that a better ground support system can be designed in practical mining applications.

SMA를 이용한 공구홀더의 자동공구교환장치 개발

Micromanufacturing is a useful system for reducing energy consumption. For micromanufacturing, tool clamping and workpiece clamping are important components to realize the machining process. Therefore, a shape memory alloy (SMA) ring type tool holder is developed. In addition, this holder needs cooling and heating processes to execute the tool clamping process. This study suggests a cooling/heating device based on peltier elements. The device will be applied to the heating/cooling process of an automatic tool changer (ATC) for the SMA tool holder. This study introduces the configuration and operating principle of the proposed ATC system. The description and prototype evaluation of this system were given. Plastic bolt and aluminum block were selected to enhance the cooling performance, and the installed tool was changed in 17 s during the experiments.

UHF RFID 태그와 GPS를 사용한 위치기반 수목관리용 RFID 시스템 구현

본 논문에서는 수목관리의 효율성과 정확성을 높이기 위해 UHF RFID 수목관리시스템 TMS(Tree Management System)를 GPS와 나무에 삽입용 태그를 사용하여 구현하였다. 나무의 정보를 인식하기 위하여 고유전율인 나무에 삽입 가능한 플라스틱 볼트 형태의 UHF RFID 태그 안테나를 설계하였다. RFID 태그 안테나는 부착된 물체의 전기적인 특성으로 인한 영향을 받으므로, 고유전율인 나무에 근접 시 태그 안테나의 임피던스 값이 변하게 되어 태그의 특성에 영향을 주게 된다. 따라서 이러한 영향을 고려하여 플라스틱 볼트 형태로 RFID 태그 안테나를 제작하였으며, 또한 본 태그를 사용하여 GPS를 이용한 TMS를 구현하여 수목관리의 위치 정보를 구글지도에(Google map) 표시함으로써 수목을 관리하는데 필요한 인건비 및 관리비 절감 등의 관리 효율성을 극대화 하였다. The paper introduces the RFID location based Tree Management System (TMS) using UHF RFID tag and GPS. The bolt shape tag has been developed since the wood material has high dielectric constant. Since the characteristics and impedance of tag antenna can be changed by the material next to the tag, the plastic bolt shape tag antenna has to be carefully designed with consideration of the high dielectric constant of the wood material. The RFID TMS system has been utilized with the bolt shape tag antenna and GPS. The TMS system uses and links Google map to locate the location of the trees. Therefore, this system allow us to manage the trees economically and efficiently.

생목 삽입용 볼트 모양의 UHF RFID 태그 안테나 설계

고유전율인 나무에 삽입 가능한 플라스틱 볼트 형태의 UHF RFID 태그 안테나를 설계하였다. 생목(生木)의 관리를 위하여 태그를 삽입용으로 볼트의 머리 부분에 설계를 하였다. 일반 태그는 고유전율인 나무에 근접하면 태그 안테나의 임피던스 특성이 변하여서 거의 동작을 하지 않으므로, 나무의 유전율을 고려하여 플라스틱 볼트의 머리 부분에 태그를 삽입하여 UHF RFID 태그 안테나를 설계 제작하였다. 반사 계수의 크기와 인식 거리를 측정 비교하였다. 이 볼트형 태그를 나무에 삽입하여 나무의 위치나 나무의 상태 등을 관리할 수 있도록 하였으며, 또한 가로수나 기타 볼트가 사용될 수 있는 물체나 장소에 적용이 가능하다. A plastic bolt shape UHF RFID tag has been developed for a live tree. The UHF tag is designed and installed into the head part of the bolt, inserted into a tree for management of tree. If the tag antenna is installed near the high dielectric constant material, the impedance of the tag antenna will be changed, and the tag does not work. Therefore, the dielectric constants of wood and plastic bolt are considered for tag antenna design. The input reflection coefficient characteristics and the reading range patterns are measured and compared. This UHF RFID tag can be applied into a live tree, and the status and location of tree can be controlled with the RFID tag. This developed UHF tag can be applied to any applications and objects using a bolt.

Nonlinear Behavior of Preloaded Bolted Joints Under a Cyclic Separating Load

The nonlinear plastic deformation behavior of a clamped bolted joint model under a separating service load is investigated using analytical, finite element, and experimental techniques. An elastic-plastic model is used for the bolt material while the joint material remains in the linear elastic range. Both the analytical and finite element analysis (FEA) models investigate the variation in the tension of a preloaded bolt due to a separating service load that acts with an offset from the bolt center. Experimental verification is provided for both the analytical and finite element results on the bolt tension variation, clamp load variation and the clamp load loss caused by the incremental plastic bolt elongation under cyclic separating force.

601 フランジ継手への塑性域締結の適用 : 熱負荷を受けるコンパクトフランジ継手の挙動(フランジガスケット締結体の力学と密封性能評価I)

601 フランジ継手への塑性域締結の適用 : 熱負荷を受けるコンパクトフランジ継手の挙動(フランジガスケット締結体の力学と密封性能評価I)

P36 アコースティック・エミッションを用いたボルトの塑性域締め管理に関する座面摩擦係数の影響(OS8)

P36 アコースティック・エミッションを用いたボルトの塑性域締め管理に関する座面摩擦係数の影響(OS8)

３次元編紐構造を有するＦＲＰボルトの２９３Ｋ，７７Ｋでの疲労強度

A glass fiber reinforcement plastic bolt (FRP bolt) has several good properties such as corrosion resistance or electrical insulation. Therefore, it exhibits an excellent performance in a suitable service environment or operation condition.In this study, the FRP bolt which has center roving and braid structure was fatigued under controlled load at 293K and 77K. And its deformation behavior during a fatigue process and its fatigue life were discussed based on the change of crack density in the FRP bolt.As the results, the following conclusions are obtained:(1) The fatigue strength of three types of FRP bolts tested became lower as its tensile strength became low. Especially, when the diameter of center roving in the FRP bolt decreased, the fatigue strength became below enormously.(2) No crack was observed in the center roving region. But it was clarified that the change of crack density observed in a braid region corresponded to the increment of displacement at a maximum or a minimum load, and that the cyclic range of displacement did not change so much.(3) There was a period in the fatigue process, in which the displacement at a maximum load increased linearly. By using the increment of displacement per cycle in this period, the fatigue lives were able to be expressed by only one curve regardless of bolt types, but it depended on test temperature.

CONTINUOUS, DIRECT MEASUREMENT OF ICP BY A SUBARACHANOID BOLT IN ASPHXYIATED TERM NEONATES

A newly developed infant subarachnoid bolt was used to continuously and directly monitor intracranial pressure (ICP) in four severely asphyxiated (Apgars 11 and 25) full-term neonates. The plastic bolt was inserted through a dural puncture and secured to the margins of a right frontal bone craniotomy. No hemorrhage, CSF leak, infection or mechanical dislodgement occurred. The bolt was successfully used until the patients' death at postnatal ages 30, 42, 71 and 84 hours. Direct (bolt) ICP values were polygraphically recorded and correlated with simultaneous indirect (transfontanelle) ICP values, mean arterial blood pressure, clinical status and seizures confirmed by EEG. After the transfontanelle pressure transducer was applied with sufficient external tension to produce indirect ICP values that matched direct values, subsequent indirect ICP measurements correlated well from 4 to 13 torr (direct/indirect ratio: M = 1.07; range = 0.8 to 1.5). Indirect ICP measurements consistently and significantly underestimated true ICP from 14 to 35 torr (direct/indirect ratio; M = 2.3; range 2.1 to 3.2). Clinical neurological and/or EEG abnormalities preceded (by age 28 hrs) peak ICP (peak ICP = 18 torr) in all infants. A modest (4 torr) ICP elevation accompanied only 2 of 128 brief (duration = 39 sec; range = 12 to 180 sec), focal electrographic seizures. We conclude that direct ICP measurements by a subarachnoid bolt in appropriately selected, critically ill neonates can be safely achieved and may be more reliable than transfontanelle measurements.