Clamping System Research Articles

A standardized head-fixation system for performing large-scale, in vivo physiological recordings in mice

BackgroundThe Allen Institute recently built a set of high-throughput experimental pipelines to collect comprehensive in vivo surveys of physiological activity in the visual cortex of awake, head-fixed mice. Developing these large-scale, industrial-like pipelines posed many scientific, operational, and engineering challenges. New methodOur strategies for creating a cross-platform reference space to which all pipeline datasets were mapped required development of 1) a robust headframe, 2) a reproducible clamping system, and 3) data-collection systems that are built, and maintained, around precise alignment with a reference artifact. ResultsWhen paired with our pipeline clamping system, our headframe exceeded deflection and reproducibility requirements. By leveraging our headframe and clamping system we were able to create a cross-platform reference space to which multi-modal imaging datasets could be mapped. Comparison with existing methodsTogether, the Allen Brain Observatory headframe, surgical tooling, clamping system, and system registration strategy create a unique system for collecting large amounts of standardized in vivo datasets over long periods of time. Moreover, the integrated approach to cross-platform registration allows for multi-modal datasets to be collected within a shared reference space. ConclusionsHere we report the engineering strategies that we implemented when creating the Allen Brain Observatory physiology pipelines. All of the documentation related to headframe, surgical tooling, and clamp design has been made freely available and can be readily manufactured or procured. The engineering strategy, or components of the strategy, described in this report can be tailored and applied by external researchers to improve data standardization and stability.

The optimization of container transport on a ship type PSV

In this paper, we studied how containers need to be transported on a PSV ship. The deterioration of the containers during the transport can get a result in the destruction on the goods. All the drawings were made by us in the NX 12 software from Siemens. Furthermore, the analysis of the container clamping system was performed by the finite element method using the NX 12 Siemens software. Structural dimensions following an original project, were used to the achievement of a PSV (Platform Supply Vessel) ship in design. Although, PSV ships are relatively small, they have a complex design. The purpose of these ships types is to transport freight and weights bigger and bigger. This is the reason why we close to present in this work only the optimization of containers on PSV ships.

The mechanism’s study of fixing a container on a freight wagon type Rgs

In freight transport is constantly evolving in the world. An important role in development of freight transport is the increasing usually a speed to 180 km/h of freight trains. In multimodal transport, all the goods are transported in containers. Therefore, the freight is mostly containerized. Several containers in freight trains are transported on Rgs freight wagons. On Rgs platforms of freight wagons are bolts of which the containers are fixed. The role of these bolts is very important because when the train takes the curve or brakes ward, containers could leave the wagon’s platform. In this paper, we represented a Rgs Wagon loaded with two containers. We have to mention that the dimensions of wagon and containers have been made using original projects. Furthermore, we are approached the theoretical aspects referring to the clamping system. We set out to accomplish a through search of both the used bolt to Rgs wagons and new model of bolt. This research was caried out with the help of finite elements method. The design part and the study with finite elements were made in NX 12 software from Siemens. Because of these bolts types they following stress: normal, shear and von Mises. As a consequence, we deduced that the second bolt type is more reliable.

Hydrogen-Induced Cracking of 500 HBW Steels Studied Using a Novel Tuning-Fork Test with Integrated Loadcell System

Hydrogen embrittlement is a well-known problem with high-strength steels. An important aspect of hydrogen embrittlement research is the effect of the prior austenite grain (PAG) structure on hydrogen-induced fracture. The microstructural anisotropy of PAG structure depends on the steel manufacturing process. In this study, 500 HBW martensitic steels with different PAG structures are investigated with a novel tuning-fork test that utilizes an integrated loadcell system. The loadcell clamping system is used during hydrogen charging, allowing tracking of the applied force throughout the tests, which enables detection of separate phases of cracking and time-to-fracture. The elongated PAG morphology produces different results depending on the crack path direction in relation to the rolling direction, whereas the equiaxed PAG morphology does not manifest an orientation dependence. Depending on the PAG shape, also the fracture morphology differs. Time-to-fracture results show that elongated grain morphologies with transgranular quasi-cleavage crack propagation are more beneficial against hydrogen-induced fracture than equiaxed grain structure with intergranular crack propagation. These results demonstrate that the shape of the PAG structure plays an important role in the crack propagation mechanism and that it is important to consider the possible direction of hydrogen-induced cracks in the final structural applications.

Remote Fibre Laser Welding of Advanced High Strength Martensitic Steel

The study presents the results of remote robotic laser welding of advanced high strength Docol® 1200 M martensitic steel. One mm thick samples were welded in a lap joint configuration using a special clamping system. Welding was done using a continuous-wave (CW) fibre laser with a constant welding power of 300 W and constant focus diameter Ø 1.8 mm. Welding was done using 12 different welding speeds in the range from 0.15 to 1 m/min, whereas the inclination angle was kept constant at 0°. The influence of various welding speeds and linear heat inputs during welding on microstructural changes were examined by the occurrence of acicular and allotriomorphic ferrite or martensite. Results revealed big influence of the clamping system on the accumulation of the laser beam energy, heat sink and consequently weld size and geometry, as well as its microstructure and joint strength. Tensile-shear strength, microstructure and hardness results confirmed laser power of 300 W and 0.6 m/min welding speed as the optimal parameters, at which a martensitic structure was obtained in the weld. The width of the heat affected zone (HAZ) in this case is 1100 μm.

Investigating the effect of residual stress on hydrogen cracking in multi-pass robotic welding through process compatible non-destructive testing

Abstract In this paper, the effect of Welding Residual Stress (WRS) on the size and morphology of hydrogen-induced cracks (HIC) is studied. Four samples were manufactured using a 6-axis welding robot and in two separate batches. The difference between the two batches was the clamping system used, which resulted in different amounts of welding deformation and WRS. The hydrogen cracks were intentionally manufactured in the samples using a localised water-quenching method, where water was sprayed over a specific weld pass in a predetermined position. The Phased-Array Ultrasonic Testing (PAUT) system was implemented during the welding process (high-temperature in-process method), to detect the HIC in real-time. The WRS in both batches was measured using the hole-drilling method, where a difference in transversal residual stress of 78 MPa was found between the two samples. Based upon both the PAUT results and microscopic investigations, the batch with higher WRS resulted in larger size and number of HIC. For the first time, the negative effect of WRS on HIC has been monitored in real-time using high-temperature in-process inspection. This was achieved using an innovative approach, introduced in this paper, to repeatably manufacture high and low WRS samples in order to control the size and location of subsequent HIC.

In-beam creep of SiCf/SiC minicomposites under uniaxial tensile loading

A newly developed clamping system for ceramic specimen is described in the present report. By using this system, the uniaxial tensile loading was first successfully applied up to fracture (950 MPa) on a SiCf/SiC minicomposite. A minicomposite is a 1D model composite. It consists of a SiC-based fiber tow embedded in a SiC matrix, which has a diameter of about 0.5 mm. Afterwards, the irradiation creep properties of SiCf/SiC minicomposites were studied. In-situ creep was performed in an in-beam creep device under uniaxial tensile stresses from 40 to 382 MPa during homogeneous helium irradiation. Homogenous irradiation was carried out by helium implantation with energies varying from 0 to 45 MeV. The displacement dose rate was 1.2 × 10−6 dpa/s. The average temperature was controlled to 700 and 900 °C within ±15 °C. Irradiation creep compliance of minicomposite was measured to be 3.07 × 10−5 and 5.43 × 10−5 dpa−1 MPa−1 at 700 °C and 900 °C, respectively.

Machining vibration monitoring based on dynamic clamping force measuring in thin-walled components milling

In milling of thin-walled structures such as impellers or blisks, critical workpiece vibrations occur due to the excitation by the cutting forces and the dynamic interface between the workpiece and the fixture. Vibrations may cause instable state of the milling process, thus decreasing the production outcome by causing rejects. In respect to the milling process of thin-walled workpiece, a challenging task is to monitor the critical vibrations occurred in the workpiece itself or the contact surface between the workpiece and the clamping system. Vibrations can be reflected in the clamping system, and thus the clamping force variation monitoring is a potential scenario or solution to the challenging task. This article introduces a measurement prototype for the real-time dynamic clamping force monitoring. With respect to the measurement of clamping force, two case studies are carried out by a direct sensing method with PVDF thin-film sensors. In the first study, the measurement prototype with embedded PVDF sensors is located on the dynamometer, and an additional eddy-current transducer is applied for monitoring the workpiece deflection during the milling process. Deflection signals and cutting force signals from dynamometer are used as two referential signals to demonstrate the reliability of the prototype with embedded PVDF sensors. In the second study, milling test with the same tool and workpiece is implemented with only PVDF sensors monitoring. Dynamic clamping signal varying with different cutting durations in time, frequency, and time-frequency domain and different milling surface results is performed. Relationship between the collected signals and machining results is preliminarily analyzed. Case studies with thin-walled workpiece show the performance of the measurement prototype.

Investigation of contact pressure distribution on gas diffusion layer of fuel cell with pneumatic endplate

Polymer electrolyte membrane fuel cell is a promising energy conversion device because of its high energy density, high efficiency and low emissions. Contact pressure on gas diffusion layers plays an important role in the performance improvement of polymer electrolyte membrane fuel cells by optimizing the ohmic and concentration losses. In this paper, geometric parameters of a pneumatic clamping system are optimized using a central composite design method and finite element simulations to obtain the most uniform contact pressure distribution on gas diffusion layers. The experimental data obtained by the pressure mapping system have been employed to validate the results of the optimized clamping system. The embedded pressure measurement films are placed in the designed polymer electrolyte membrane fuel cell with an active area of 400 cm2. The results reveal that the maximum difference between numerical and experimental results is less than 8%. Moreover, the contact pressure distributions over the gas diffusion layer for the clamping systems of pneumatic and conventional endplates are compared. The results demonstrate that the weight and efficiency of the clamping system with optimized pneumatic endplate is significantly better than the clamping system with conventional endplates.

Performance of the Large Hadron Collider's Cryogenic Bypass Diodes Over the First Two Physics Runs, Future Projects, and Perspectives

Cryogenic bypass diodes have been installed in all superconducting dipole magnets (1232) and quadrupole magnets (392) of the Large Hadron Collider (LHC) at CERN, and operated during the physics runs since 2009. The bypass diodes are a fundamental ingredient of the quench protection system for those main dipoles and quadrupoles magnets. The diodes are located inside the magnet cryostats, operating in superfluid helium and exposed to ionizing radiation. The connection between the superconducting magnet and the bypass diode is made through a mechanical clamping system and copper bus bars. Since their first installation, all LHC diodes have undergone at least two full thermal cycles (from 1.9 K to room temperature and back to superfluid helium temperature). The evolution of electrical parameters as well as improvements and modifications made over a period of 10 years are reviewed in this paper. With CERN preparing for LHC's High Luminosity era, the long-term strategy for cold diodes is presented, based on the overall results and experience gathered so far, including the studies related to the tolerance with respect to the radiation doses and neutron fluences expected.

Mechanical Evaluation of Titanium Plates for Osteoesynthesis High Neck Condylar Fracture of Mandible.

Background: In the literature no information about plates for the high-neck mandibular condylar osteosynthesis could be found despite that 30 plate designs have been published. The main course consider the basal condylar or diacapitular fractures. The aim of the study was to test mechanically all available designs (only 4 of 30 was proper) on polyurethane mandibles using an individually designed clamping system. Methods: Forces required for a 1 mm displacement of fixed fracture fragments and incidents of screw loosening were recorded. Results: It has occured that dedicated plates for fixation are much weaker than set of two straight plates (p < 0.0001). General observation is the bigger plate and more screws, the better rigid stable osteosynthesis of mandibular condyle, however, there are limitations in plates design for high-neck fractures resulted in restricted operation field. Conclusion: Double straight plates occured to be the best mechanical fixation for high-neck fractures of the mandibular condyle. Maybe other existing plates could be used but only after prebending or that fracture required novel dedicated plates design.

Clamping and substrate plate system for continuous additive build-up and post-processing of metal parts

The manufacturing share of laser powder bed fusion (L-PBF) increases in industrial application, but still many process steps are manually operated. Additionally, it is not possible to achieve tight dimensional tolerances or low surfaces roughness. Hence, a process chain has to be set up to combine additive manufacturing (AM) with further machining technologies. To achieve a continuous workpiece flow as basis for further industrialization of L-PBF, the paper presents a novel substrate system and its application on L-PBF machines and post-processing. The substrate system consists of a zero-point clamping system and a matrix-like interface of contact pins to be substantially connected to the workpiece within the L-PBF process.

Effect of curing environment on the tensile behaviour of FRCM composites

FRCM composites based on long continuous fibres embedded in inorganic mortar matrix has been increasingly used to strengthen existing structures. The mechanical behaviour of FRCMs and their effectiveness in strengthening applications are highly dependent on the mechanical properties of the fibres and the mortar matrices. Research has revealed that the temperature and humidity of the curing environment has a pivotal impact on the development of the mechanical properties of cementitious mortar. Therefore, in this paper, the influence of the curing environment under moist or dry conditions with different temperatures on the degree of hydration and tensile strength of cementitious mortar are investigated. Then, direct tensile tests are applied to 30 steel-FRCM coupons which are cured in different environments to obtain the corresponding full range of tensile stress-strain responses. The effects of the strain measurement system, coupon size, clamping system and curing environment are investigated. Finally, the experimental tensile stress-strain response curves of the FRCM coupons are validated with the analytical results derived from the three different approaches to draw conclusions.

O6-methylguanine-DNA methyltransferase promoter methylation and isocitrate dehydrogenase mutation as prognostic factors in a cohort of Saudi patients with glioblastoma.

ABSTRACTBACKGROUND: Treatment of glioblastoma (GB), the most common malignant primary brain tumor in adults, can include alkylating chemo-therapeutic agents. Two molecular biomarkers of treatment response are MGMT (O6-methylguanine-DNA methyltransferase) promoter methylation and IDH (isocitrate dehydrogenase) mutations, which prevent repair of tumor cell DNA damage caused by alkylating chemotherapy. The status of MGMT promoter methylation and IDH mutation are associated with longer survival and a better response to chemotherapy.OBJECTIVE: Assess the prognostic value of MGMT methylation status and IDH mutation in adult Saudi glioblastoma patients.DESIGN: Retrospective, comparative survival analysis.SETTING: Tertiary care center.PATIENTS AND METHODS: The status of the MGMT promoter methylation and IDH mutation was assessed in adult patients diagnosed with GB between 2006 and 2019. A PCR-based assay was used to analyze for methylation of the MGMT promoter. A qualitative assay combining PCR clamping and amplification refractory mutation system technology was used to search for any of the 12 most common mutations in IDH1 and IDH2. Differences in survival were compared between those with and without MGMT promoter methylation and IDH mutation and between other subgroups.MAIN OUTCOME MEASURES: Survival of GB patients relative to MGMT promoter methylation and IDH mutation status.SAMPLE SIZE: 146 patients (80 males and 66 females).RESULTS: Of 43 (29.5%) cases tested for MGMT promoter methylation, 14 (32.5%) were positive. Of 65 (44.5%) cases screened for IDH mutation, 6 cases (9.2%) tested positive. The 36-month survival rate was 47% for the MGMT methylated cohort compared to 27% for their unmethylated counterparts. The 18-month survival rate for the IDH-mutant was 75% compared to 48% for their IDH-wildtype counterparts.CONCLUSION: The findings confirm the positive impact of both MGMT promoter methylation and IDH mutation on the overall survival of Saudi GB patients.LIMITATIONS: Single institute study with relatively few tested cases.CONFLICT OF INTEREST: None.

Instrumented clamping device and numerical simulations to study machining distortion

Machining part distortion is due to residual stresses induced by previous manufacturing processes. This study aims to evaluate the influence of machining conditions on AISI 316L plate distortion. Therefore, a special experimental device with force sensors integrated in the clamping system and numerical model of distortion were developed. Residual stresses due to previous machining processes were measured using a layer removal method and neutron diffraction technique. Then, distributions of these residual stresses were integrated in a developed model of machining distortion, which considers the clamping and machining sequence effects after each stage of the toolpath. A comparison of the experimental and numerical results revealed that the finite element method can adequately predict machining distortion. The results also suggest that clamping and machining sequence can affect part distortion.

3D printed clamps improve spine specimen fixation in biomechanical testing

This study presents an anatomically customizable fixation technique for biomechanical spine experiments using a 3D printed clamping system. The aim of this study is to evaluate the feasibility and compare the fixation rigidity of the novel technique to PMMA potting with and without screw augmentation. For this purpose, 16 thoracic and lumbar functional spine units of bovine, porcine, ovine and human cadavers (4 each) were consecutively fixed with all three techniques and loaded in six degrees of freedom. The combined relative movement between the cranial and caudal vertebral body and their corresponding fixtures were recorded using a 3D motion capture system. The 3D printed clamps did provide multiple advantages, showed no failures and the fixation rigidity was superior to potting in all loading directions and superior to screw-augmented potting in two of six loading directions (p < 0.05). In conclusion, the here proposed novel fixation method showed equal to superior properties in comparison to both other methods used in this study. When considering all characteristics of 3D printing, 3D printed fixtures can be an effective alternative to potting.

Improving the Hybrid Electromagnetic Clamping System by Reducing the Leakage Flux and Enhancing the Effective Flux

In most industrial fields, mechanical clamping methods are traditionally used to transport heavy loads such as steel structures by fastening the load using bolts and nuts. However, this method can lead to industrial accidents during load transfer and does not consider the weight of the load. Recently, permanent magnet clamping methods have been proposed to prevent such accidents; for example, hybrid electromagnetic clamping systems (H-EMCSs), which combine permanent magnets and electromagnets and can adjust the clamping force according to the load weight. However, few studies have attempted to improve the electromagnetic structure and effective magnetic flux of H-EMCS. Specifically, H-EMCSs control the clamping force using several hybrid electromagnetic modules (H-EMMs); however, the leakage magnetic flux increases with an increasing number of H-EMMs. Therefore, the clamping force should be improved to avoid increasing the leakage magnetic flux. In this study, we propose a novel H-EMM structure and improve its electromagnetic force characteristics by changing the core shape and dimension effect in order to reduce the leakage flux and maximize the effective magnetic flux. Furthermore, we verify the improved electromagnetic force properties by experimentally validating the proposed model. This research can improve the safe and effective transfer of industrial loads.

Forces Causing One-Millimeter Displacement of Bone Fragments of Condylar Base Fractures of the Mandible after Fixation by All Available Plate Designs.

Background: There has been no direct comparison of all existing plates dedicated for fracture osteosynthesis of mandibular condyle base until now. The aim of the study was to test mechanically all available designs of titanium plates on the market on polyurethane mandibles using an individually designed clamping system. Methods: Forces required for a 1 mm displacement of fixed fracture and incidents of screw loosening were recorded. Results indicated the best mechanical plates among all existing designs available. Results: It has occured that some of osseofixation plates should not be used any more, whereas some shape of the single plates are similar shape to two single plates shape are regarded as the best osseofixation method for condyle base fracture. Conclusion: General observation is the bigger plate and more screws, the better rigid stable osteosynthesis of mandibular condyle base. 4 plates of current designs of total 30 tested series can be recommended for open rigid internal fixation of fractures of the base of the mandibular condyle. The rest of 26 existing plates should not be used in condylar base fractures.

Increasing the Measuring Accuracy of a Sensory Swing Clamp by Multi-Sensor Evaluation

Abstract The growing flexibility of modern production systems complicates the quality assurance and process safety of mechanical processing. As an import component of milling machines, the workpiece clamping systems plays a quality-determining role within every milling process. Thus, a sensory workpiece clamping system that utilizes sensory swing clamps was developed in former research work in order to provide monitoring capabilities. This contribution deals with the experimental analysis of the multiple integrated sensors of the sensory swing clamp and the characterization of their measuring capability toward different measurands. By means of the stepwise linear regression method, different models were developed that enable the determination of the clamping force, the hydraulic pressure, and the piston position. The results verify that the multi-sensor evaluation significantly increases the measuring accuracy of a sensory swing clamp. Thus, the measuring accuracy is measurable with a standard deviation of 0.05 MPa for the hydraulic pressure, 101 N for the clamping force, and 0.62 mm for the piston position. Furthermore, the practicability and flexible use at varying boundary conditions is proved.

Effects of Machining Parameters on the Quality in Machining of Aluminium Alloys Thin Plates

Nowadays, the industry looks for sustainable processes to ensure a more environmentally friendly production. For that reason, more and more aeronautical companies are replacing chemical milling in the manufacture of skin panels and thin plates components. This is a challenging operation that requires meeting tight dimensional tolerances and differs from a rigid body machining due to the low stiffness of the part. In order to fill the gap of literature research on this field, this work proposes an experimental study of the effect of the depth of cut, the feed rate and the cutting speed on the quality characteristics of the machined parts and on the cutting forces produced during the process. Whereas surface roughness values meet the specifications for all the machining conditions, an appropriate cutting parameters selection is likely to lead to a reduction of the final thickness deviation by up to 40% and the average cutting forces by up to a 20%, which consequently eases the clamping system and reduces machine consumption. Finally, an experimental model to control the process quality based on monitoring the machine power consumption is proposed.