Rod Length Research Articles

Riveting damage behavior and mechanical performance assessments of CFRP/CFRP single-lap gasket-riveted joints

Riveting is one of dominant joining methods in carbon fiber reinforced polymer (CFRP) structures, however, riveting is prone to cause CFRP local damage. In this study, a riveting method with a gasket was developed for CFRP/CFRP joints. Riveting damage behaviors were assessed, and the parametric study of the rivet rod length was also carried out. Moreover, both tensile shear and pull-off performances were assessed under quasi-static loading, including the discussion of failure modes. Results demonstrated that the riveting damage mainly occurred in CFRP plies near the rivet deformed head due to the excessive deformation of the rivet tail along both rivet radial direction and rivet axial direction. The over long rivet rob caused a askew deformation of the rivet tail resulting in the most serious CFRP damage. Joining the CFRP/CFRP structures by using an appropriate gasket can obviously reduce the riveting damage and enhance the joining strength of the composite specimen. This paper provided a useful joining method for aircraft composite structures.

Total longitudinal potential energy of interaction between parallel charged rods of finite size

We present a formula for the total potential energy of interaction between two parallel charged prismatic rods of finite size as a function of longitudinal inter-rod displacement (TLPE), obtained by calculating the repulsive electrostatic potential energy (using the nonlinear Poisson-Boltzmann equation) and the attractive van der Waals (VDW) potential energy between the rods in skewed configurations. The full profile of the TLPE curves is like an inverted bell, whose (top) width is twice the rod length, and depth is the same as that of the secondary minimum of the Derjaguin-Landau-Verwey-Overbeek (DLVO) potential for the rods.Using the TLPE function, we estimated root mean square of longitudinal displacements of fluctuating rods of 250 × 50 × 50 nm3 and a scaled surface potential of 5 for lateral inter-rod separations, d = 20 and 25 nm, e.g., in 5-rod systems, which showed non-negligible values of 24–87 nm.

Chaos in a Pendulum Adaptive Frequency Oscillator Circuit Experiment

Adaptive oscillators can learn and encode information in dynamic, plastic states. The pendulum has recently been proposed as the base oscillator of an adaptive system. In a mechanical setup, the horizontally forced pendulum adaptive frequency oscillator seeks a resonance condition by modifying the length of the pendulum's rod. This system stores the external forcing frequency when the external amplitude is small, while it can store the resonance frequency, which is affected by the nonlinearity of the pendulum, when the external amplitude is large. Furthermore, for some frequency ranges, the pendulum adaptive frequency oscillator can exhibit chaotic motion when the amplitudes are large. This adaptive oscillator could be used as a smart vibratory energy harvester device, but this chaotic region could degrade its performance by using supplementary energy to modify the rod length. The pendulum adaptive frequency oscillator’s equations of motions are discussed, and a field-programmable analog array is used as an experimental realization of this system as an electronic circuit. Bifurcation diagrams are shown for both the numerical simulations and experiments, while period-3 motion is shown for the numerical simulations. As little work has been done on the stability of adaptive oscillators, the authors believe that this work is the first demonstration of chaos in an adaptive oscillator.

Calibration rod selection strategy in RCSA-based method for reliable calculation of milling tool-tip FRFs in rotating conditions

The measurement of milling tool-tip frequency response functions (FRFs) in rotating conditions is challenging in practice. Methods based on the receptance coupling substructure analysis (RCSA) can obtain rotating tool-tip FRFs using normal modal test devices; thus, they have received extensive attention in the research community. The typical RCSA framework first adopts a calibration rod for measuring rotating FRFs. Then, it analytically calculates the desired tool-tip FRFs through the RCSA theory. As the calculation process involves matrix inversion, high-quality FRF data is required. However, experimentally measured FRFs in rotating structures contain severe noise, leading to an unreliable calculation. This paper presents a novel error analysis model to investigate the propagation mechanism of measurement errors in the typical RCSA framework. Results show that measurement errors would cause errors in the length of the coupled substructure while introducing scaling effects. The calibration rod is found to be vital for RCSA calculation reliability. The patterns of the calculation error are opposed when adopting a short or long calibration rod. Then, a calibration rod selection strategy is proposed. The strategy makes full use of the high measurement quality near the resonance in rotating FRFs and achieves the dominant mode frequency matching between the clamped rod and the clamped tool by adjusting the rod length. Simulations validate the error analysis model and the calibration rod selection strategy. Experimental results also show that the optimal selection of the calibration rod could improve the calculation reliability of rotating tool-tip FRFs in the typical RCSA framework.

CFD ANALYSIS OF SECTOR COMBUSTION SIMULATION IN FOUR STROKE DIRECT INJECTION DIESEL ENGINE

In this article an attempt has been made in cylinder sector combustion CFD simulation of four stroke petrol engines using ANSYS fluent 2019 to obtain very useful results using a modelled engine. In order to improve engine quality, understanding on sector combustion properties in engine cylinder is of major importance because combustion condition significantly influences engine efficiency, Capabilities in providing optimum combustion conditions which include high optimum swirl ratio, and optimum tumble ratio in respective engine can result in enhancement of engine power and comfort, along with reduction of fuel consumption, exhaust emission and noise. The simulation is applied for a geometry with crank radius (55mm), connecting rod length (165mm), Engine speed (1800rpm), which is developed to study the effect combustion inside the cylinder. Piston starts from bottom dead center about 541degrees and the maximum pressure reaches at 716 degrees. The pressure increases from 542 crank angle degree to 716 crank angle degree and reaches its maximum value at 716 crank angle degrees. The Maximum pressure at the end of compression is 63.69Kpa and temperature is 1200K. The maximum penetration length of injection is occurred at crank angle 722 degree is 0.014mm.

Study on stress variation of advance fiberglass anchor bolts during tunnel excavation process

One of the main causes for excessive deformation within a tunnel is due to the instability of the soil or soft rock ahead of the excavation face. Fiberglass bolts have been shown to be a useful advance reinforcement method for the excavation face. In this paper, an improved ADECO-RS (Analysis of controlled deformation in rock and soils) method had been proposed for soft rock mountain tunnels, in terms of the partial (mainly the upper bench) excavation face reinforcement and also for the bench excavation method. Strain gauges were used to test the micro-strain in the fiberglass bolt to investigate how the axial force of the fiberglass bolt varied during the tunnel excavation. In addition, combined with the field tunnel deformation monitoring data, the relationship between the reinforcement parameters of the fiberglass bolts and the tunnel construction phase were discussed. The research results show that: (1) The stress state of the anchor rod is related to the reinforcement length of the anchor rod; (2) Excavation within the lap area of the fiberglass bolt leads to an increase in the axial force of the bolt, while excavation outside the lap area of the fiberglass bolt has no effect on the anchor; (3) Reducing the reinforcement area of rock mass will affect the stability of the excavation. To ensure the stability of the excavation face, the initial support construction loop should be completed as soon as possible; (4) In a future project with similar conditions, the recommended lap length of the fiberglass bolt could be 3 m utilizing the fiberglass bolt grouting face reinforcement method.

Predictors of Rod Length Gain and Sagittal Alignment Change After Magnetically Controlled Growing Rod Lengthening.

This was a retrospective cohort study. There are preoperative characteristics that predict rod lengthening of magnetically controlled growing rods (MCGR). The lengthening of MCGR will lead to increased kyphosis. The amount of length gained by MCGR is variable, and predictors are lacking. Similarly, sagittal plane changes over the MCGR lengthening period have not been investigated. Patients with MCGR and a minimum 2-year follow-up were identified and those with previous spine surgery were excluded. Preimplantation, postimplantation, and last follow-up postlengthening radiographs were examined. Multiple linear regression analyses were used for rod length gain predictors. Fifty-six patients with early-onset scoliosis met inclusion criteria: nine idiopathic, five congenital, 14 neuromuscular, 20 syndromic, and eight skeletal dysplasia patients. No difference was seen between subtypes of early-onset scoliosis for rod length gain ( P =0.62). Shorter preoperative T1-T12 height and higher curve correction rate after implantation were significant predictors for rod length gain ( P <0.001). Preoperative major curve magnitude and kyphosis were not significant predictors. Flattening of the spine around the actuator and compensative increase in T1-T5 kyphosis were seen secondarily after MCGR implantation. Maximum sagittal kyphosis, T1-T5 kyphosis, and T5-T12 kyphosis did not change during lengthening. Lumbar lordosis significantly decreased postimplantation (first erect) but then increased during lengthening. Pelvic incidence and sacral slope both increased during lengthening, but this may be age related. Patients who gained the most rod length with MCGR were those with an initially shorter T1-T12 height and better initial curve correction at implantation, likely representing that implants work best in small patients with flexible curves. Diagnosis, preoperative curve magnitude, and thoracic kyphosis were not related to rod length gain. Thoracic kyphosis did not deteriorate over the lengthening phase. Level III-retrospective cohort study.

Mutagenic analysis of the bundle-shaped phycobilisome from Gloeobacter violaceus.

Gloeobacter violaceus is an ancient cyanobacterium as it branches out from the basal position in the phylogenic tree of cyanobacteria. It lacks thylakoid membranes and its unique bundle-shaped type of phycobilisomes (PBS) for light harvesting in photosynthesis are located on the interior side of cytoplasmic membranes. The PBS from G. violaceus have two large linker proteins that are not present in any other PBS, Glr2806, and Glr1262, which are encoded by the genes glr2806 and glr1262, respectively. The location and functions of the linkers Glr2806 and Glr1262 are currently unclear. Here, we report the studies of mutagenetic analysis of glr2806 and the genes of cpeBA, encoding the β and α subunits of phycoerythrin (PE), respectively. In the mutant lacking glr2806, the length of the PBS rods remains unchanged, but the bundles are less tightly packed as examined by electron microscopy with negative staining. It is also shown that two hexamers are missing in the peripheral area of the PBS core, strongly suggesting that the linker Glr2806 is located in the core area instead of the rods. In the mutant lacking the cpeBA genes, PE is no longer present and the PBS rods have only three layers of phycocyanin hexamers. The construction of deletional mutants in G. violaceus, achieved for the first time, provides critical information for our understanding of its unique PBS and should be useful in studies of other aspects of this interesting organism as well.

Predictive Model of a Mole-Type Burrowing Robot for Lunar Subsurface Exploration

In this work, a dynamic model is proposed to simulate the drilling and steering process of an autonomous burrowing mole to access scientific samples from the deep subsurface of the Moon. The locomotive module is idealized as a rigid rod. The characteristic parameters are considered, including the length, cross-section diameter, and centroid of a cylindrical rod. Based on classical Lagrangian mechanics, a 3-DOF dynamic model for the locomotion of this autonomous device is developed. By introducing resistive force theory, the interaction scheme between the locomotive body and the lunar regolith is described. The effects of characteristic parameters on resistive forces and torques are studied and discussed. Proportional-derivative control strategies are introduced to calculate the tracking control forces following a planned trajectory. The simulation results show that this method provides a reliable manipulation of a mole-type robot to avoid obstacles during the tracking control process in layered sediments. Overall, the proposed reduced-order model is able to simulate the operating and controlling scenarios of an autonomous burrowing robot in lunar subsurface environments. This model provides intuitive inputs to plan the space missions of a drilling robot to extract subsurface samples on an extraterrestrial planet such as the Moon or Mars.

Flow field analysis of long rod hypervelocity penetration into semi-infinite concrete target

An ovoid of Rankine was used to describe the flow field shape, and a flow field analysis model was constructed to depict the penetration process. The depth of penetration, tunnel radius, change in the long rod length, and penetration velocity was calculated using this model. The calculation results were in good agreement with experimental data from previous studies. The influence of long rod material parameters on penetration was also analyzed. The following results were obtained: the depth of penetration increased slowly with increasing impact velocity at hypervelocity penetration, the erosion rate of the long rod was constant during the penetration process, and the length of the long rod was the most sensitive parameter affecting the depth of penetration, and the hole radius and long rod diameter had an approximately linear relationship and both increased with rod density.

Chemical, surface, and thermal studies of mixed oxides cupric oxide (CuO), lanthanum oxide (La2O3), and graphene oxide for dye degradation from aqueous solution

Mixed oxy-compositions are lately used for water treatment that might be exploited as photo-catalyst, and adsorptive materials for the disposal of water pollutants. Cupric oxide (CuO), lanthanum oxide (La2O3), and graphene oxide (GO)-based nanocomposites show an interest in water treatment applications owing to the adsorptive feature of carbon-based nanoparticles (NPs), besides low band gap of metal oxides that boosts photo-catalytic process. CuO/La2O3/GO-based nanocomposites are prepared and tested for their thermal stability, and dye removal activity. The change in nanocomposites structure upon the incorporation of CuO and La2O3 into GO nanosheets is inspected via TEM micrographs showing a decline in lanthana rod length to be 200 nm on average. Additionally, the improved roughness structure and the compact grain size appear in SEM micrographs reports CuO grain size reduction reaching an average size of 250 nm. The roughness parameters of CuO/La2O3/GO are extraordinarily heightened in which the supreme value of roughness average is 7.6 nm. Ternary nanocomposite exhibits a maximum value (85%) as a methylene blue (MB) dye removal. Based on these obtained results, the fabricated nanocomposites are recommended for water treatment due to their enriched physicochemical and morphological features as well as the better thermal stability and exerted dye removal activity.

Motion reliability analysis of crank-slider mechanism with multi-tolerances

An error analysis method with mixed clearance and multi-dimensional tolerances for the offset crank-slider mechanism was proposed in this research. Taking reliability and motion defect-free as performance probability constraints, an optimized design model of mechanism motion accuracy reliability with multi-tolerances was established, which aimed to minimize the maximum failure probability of trajectory point motion accuracy. Taking the rod length and dimensional tolerances into account, the global motion region of the slider in 12 schemes was optimized. Based on the optimization, the optimal design variables such as rod length and tolerances were obtained. The influence of mixed clearances on the reliability of the kinematic accuracy of the mechanism was analyzed quantitatively. The results show that the motion error of the forward interval of the slider is larger than that of the return interval, while the stationarity is lower. while the prismatic clearances increased from 0.01 to 0.02 and 0.03mm, the failure probability increased by 22.87% and 48.27%, respectively. With additional revolute clearances set to 0.0072mm, the corresponding additional increment of failure probability was 5.31% and 5.19%, respectively. Furthermore, enlarging the revolute clearances to 0.0193mm, the failure probability increased by 7.22% and 13.24% additionally. Based on both manufacturing cost and reliability, the design schemes were evaluated comprehensively, and reasonable suggestions for the selection of the optimal design scheme were given.

Comb-forming roller with elastic rods

A design diagram of comb formation roller in resilient stems is given. Comb-forming roller consists of support and small discs, as well as elastic rods. Elastic rods are installed along the perimeter of the diameter of the disks through their holes. Analytical dependences and mathematical models are obtained for determining the distance between disks, the diameter of disks, the diameter, length and number of elastic rods. One-factor experiments were carried out to substantiate the diameter of the disks and the number of rods. It was found that with the length of the elastic rods of the comb-forming roller 65-75 cm, the diameters of large, medium and small discs, respectively, at least 600mm, 550 mm and 200 mm, the angle of sharpening of the discs within 55-650, the issue of stems within 64 - 69 trimming and diameter bars 3 mm, intensive defeat of chunk and high- quality creation of ridges is ensured.

Prediction of Residual Deformation and Stress of Laser Powder Bed Fusion Manufactured Ti-6Al-4V Lattice Structures Based on Inherent Strain Method

The development of additive manufacturing (AM) technology provides higher feasibility for designing and manufacturing lattice structures. However, the manufacturing process usually generates residual deformation and stress, and even produces cracking, thus affecting the performance of the parts. This work establishes a simulation model of the Ti-6Al-4V lattice structures during laser powder bed fusion (LPBF) based on the inherent strain method. Effects of geometric lattice parameters (inclination angle, rod diameter, rod length) on the residual deformation and stress are analyzed. Based on the simulation results, measures for improving the quality of the lattice structures are proposed. The proposed model and simulation results can provide theoretical references for designing and manufacturing the lattice structures during practical engineering applications of LPBF.

Controlling the transport of the mixture involving active and passive rods in confined channel.

The transport of the binary mixture of self-propelled rods (SPRs) and passive rods in the asymmetric conjugate periodic channel is studied by dissipative particle dynamics (DPD) simulations. It is found that the autonomous pumping of the binary mixture of active and passive rods can be achieved by either the individual or collective behaviour of SPRs. More specifically, the transport of passive rods can be driven through the individual, collective jostlement of the active rods, and crowding out effect. The strength of self-propulsion, rod length, rod concentration, and geometric feature of the channel determines the mechanism of pumping. In addition, the drift of the binary mixture can be in the positive and negative directions of the channel or the currents of SPRs and passive rods in opposite directions and relies on the geometric feature of the channel and concentration of the two species. Overall, our simulation study offers an efficient approach of flow control for both species.

Feasibility study of longitudinal transportation

The research in this paper relates to the technical field of light load transportation, in particular to an electric upstairs car, which includes a frame, the top of the frame is fixedly equipped with a handle, the bottom of the frame is rotationally equipped with a group of wheels, the side wall near the bottom of the frame is fixedly equipped with a carrier plate, the support plate is fixedly arranged between the frames, and the box is fixedly arranged on the side of the support frame away from the carrier plate, A support rod is rotated on the opposite side of the box. The length of the support rod is larger than the diameter of the wheel. An arc surface is set on the support rod. A drive component is set in the box. The drive component is used to drive the support rod to rotate. This kind of electric car that can be transported longitudinally can reduce labor.

Bottom-up on-surface synthesis based on click-functionalized peptide bundles.

On-surface synthesis is a modern technique for the preparation of atomically low-dimensional molecular nanostructures. However, most nanomaterials grow horizontally on the surface, and the step-by-step longitudinally controllable covalent bonding reaction on the surface is rarely reported. Here, we successfully achieved bottom-up on-surface synthesis by using coiled-coil homotetrameric peptide bundles called 'bundlemers' as building blocks. Rigid nano-cylindrical bundlemer with two click-reactive functionalities at each end can be grafted vertically onto the surface or another bundlemer with complementary clickable groups by click reaction at one end, thus enabling the longitudinal bottom-up synthesis of rigid rods with an exact number of bundlemers (up to 6) on the surface. Moreover, we can graft linear poly(ethylene glycol) (PEG) to one terminal of rigid rods to obtain rod-PEG hybrid nanostructures that can be released from the surface under specific conditions. Interestingly, rod-PEG nanostructures consisting of different numbers of bundles can self-assemble in water into different nano-hyperstructures. In general, the bottom-up on-surface synthesis strategy presented here can provide a simple and accurate method to manufacture a variety of nanomaterials.

Analysis of dephasing time of plasmonic hybridization modes using a quasi-normal mode method

Measuring and regulating the localized surface plasmon (LSP) dephasing time (lifetime) of bonding and antibonding modes in nanosystems is the basis for the application of LSP devices. Here, we investigate the modulation of the dephasing time of hybridization modes generated by the coupling between dipole and quadrupole LSP modes in an asymmetric nanorod dimer by combining finite-difference time-domain numerical simulations with the quasi-normal mode (QNM) method. We surprisingly find that the dephasing time of the antibonding mode can be as long as 10.55 fs, which is 30% longer than that of the quadrupole mode supported by an isolated long rod (7.94 fs). Moreover, it is found that the dephasing times of the antibonding and bonding modes can be selectively modulated by changing the gap size or rod length in the dimer. A 6 THz difference between peak frequencies obtained from directly reading the near-field spectra and from the QNM fitting of near-field spectra is observed due to mode interactions existing with a gap size of 60 nm. This work demonstrates that QNM is a superior method in analyzing complex spectra, and it advances our understanding of the dynamical evolution of plasmonic hybrid modes.

Shear induced tuning and memory effects in colloidal gels of rods and spheres.

Shear history plays an important role in determining the linear and nonlinear rheological response of colloidal gels and can be used for tuning their structure and flow properties. Increasing the colloidal particle aspect ratio lowers the critical volume fraction for gelation due to an increase in the particle excluded volume. Using a combination of rheology and confocal microscopy, we investigate the effect of steady and oscillatory preshear history on the structure and rheology of colloidal gels formed by silica spheres and rods of length L and diameter D (L/D = 10) dispersed in 11 M CsCl solution. We use a non-dimensional Mason number, Mn (=Fvisc./Fattr.), to compare the effect of steady and oscillatory preshear on gel viscoelasticity. We show that after preshearing at intermediate Mn, attractive sphere gel exhibits strengthening, whereas attractive rod gel exhibits weakening. Rheo-imaging of gels of attractive rods shows that at intermediate Mn, oscillatory preshear induces large compact rod clusters in the gel microstructure, compared to steady preshear. Our study highlights the impact of particle shape on gel structuring under flow and viscoelasticity after shear cessation.

A new physically realisable internal 1:1 resonance in the coupled pendulum–slosh system

The problem of dynamic coupling between a rectangular container undergoing planar pendular oscillations and its interior potential fluid sloshing is studied. The Neumann boundary-value problem for the fluid motion inside the container is deduced from the Bateman–Luke variational principle. The governing integro-differential equation for the motion of the suspended container, from a single rigid pivoting rod, is the Euler–Lagrange equation for a forced pendulum. The fluid and rigid-body partial differential equations are linearised, and the characteristic equation for the natural and resonant frequencies of the coupled dynamical system are presented. It is found that internal 1:1 resonances exist for an experimentally realistic setup, which has important physical implications. In addition, a new instability is found in the linearised coupled problem whereby instability occurs when the rod length is shorter than a critical length, and an explicit formula is given.