Large Compressive Forces Research Articles

A Chemo-Mechanically Coupled DNA Origami Clamp Capable of Generating Robust Compression Forces.

DNA nanostructures have been utilized to study biological mechanical processes and construct artificial nanosystems. Many application scenarios necessitate nanodevices able to robustly generate large single molecular forces. However, most existing dynamic DNA nanostructures are triggered by probabilistic hybridization reactions between spatially separated DNA strands, which only non-deterministically generate relatively small compression forces (≈0.4 piconewtons (pN)). Here, an intercalator-triggered dynamic DNA origami nanostructure is developed, where large amounts of local binding reactions between intercalators and the nanostructure collectively lead to the robust generation of relatively large compression forces (≈11.2 pN). Biomolecular loads with different stiffnesses, 3, 4, and 6-helix DNA bundles are efficiently bent by the compression forces. This work provides a robust and powerful force-generation tool for building highly chemo-mechanically coupled molecular machines in synthetic nanosystems.

Piezoelectric energy harvester for wind turbine blades based on bistable response of a composite beam in post-buckling

A bistable piezoelectric energy harvester (PEH) is presented for harvesting power from vibrations occurring at low frequencies, as is the case of wind turbine blades. The axial compressive prestress of a piezoelectric composite beam at post-buckling serves as the bistability source, leading to high mechanical to electric power conversion. An in-house harvesting circuit connected to the piezoelectric terminals is used for demonstration of its harvesting power capabilities. A finite element (FE) model is used to analyze and optimize the coupled nonlinear electromechanical response of the PEH, including structure and circuit. A physical prototype has been manufactured and tested for validation of the electromechanical design and the FE modeling approach. Predictions and measurements indicate an increase of harvested power with applied prestress up to a transition point, where a sudden drop in power occurs. Good comparison between numerical and experimental results verified the modeling approach, whereas deviations related to physical boundary conditions at large compressive forces affected the prediction of the transition point in harvested power. The harvester produced 1.32 mW of electrical power under tonal base excitation of 1 g at 8 Hz. Hence, the nonlinear PEH has demonstrated its capability to harvest energy at frequencies much lower than its first linear modal frequency and could thus serve as a promising solution for powering IoT devices and sensors in large vibrating structures.

A Bioinspired Design of Protective Al2O3/Polyurethane Hierarchical Composite Film Through Layer-By-Layer Deposition.

Structural materials such as ceramics, metals, and carbon fiber-reinforced plastics (CFRP) are frequently threatened by large compressive and impact forces. Energy absorption layers, i.e., polyurethane and silicone foams with excellent damping properties, are applied on the surfaces of different substrates to absorb energy. However, the amount of energy dissipation and penetration resistance are limited in commercial polyurethane foams. Herein, a distinctive nacre-like architecture design strategy is proposed by integrating hard porous ceramic frameworks and flexible polyurethane buffers to improve energy absorption and impact resistance. Experimental investigations reveal the bioinspired designs exhibit optimized hardness, strength, and modulus compared to that of polyurethane. Due to the multiscale energy dissipation mechanisms, the resulting normalized absorbed energy (≈8.557MJ m-3) is ≈20 times higher than polyurethane foams under 50% quasi-static compression. The bioinspired composites provide superior protection for structural materials (CFRP, glass, and steel), surpassing polyurethane films under impact loadings. It is shown CFRP coated with the designed materials can withstand more than ten impact loadings (in energy of 10 J) without obvious damage, which otherwise delaminates after a single impact. This biomimetic design strategy holds the potential to offer valuable insights for the development of lightweight, energy-absorbent, and impact-resistant materials.

A Force-Matched Approach to Large-Strain Nonlinearity in Elasticity Imaging for Breast Lesion Characterization.

Ultrasound elasticity imaging is a class of ultrasound techniques with applications that include the detection of malignancy in breast lesions. Although elasticity imaging traditionally assumes linear elasticity, the large strain elastic response of soft tissue is known to be nonlinear. This study evaluates the nonlinear response of breast lesions for the characterization of malignancy using force measurement and force-controlled compression during ultrasound imaging. 54 patients were recruited for this study. A custom force-instrumented compression device was used to apply a controlled force during ultrasound imaging. Motion tracking derived strain was averaged over lesion or background ROIs and matched with compression force. The resulting force-matched strain was used for subsequent analysis and curve fitting. Greater median differences between malignant and benign lesions were observed at higher compressional forces (p-value < 0.05 for compressional forces of 2-6N). Of three candidate functions, a power law function produced the best fit to the force-matched strain. A statistically significant difference in the scaling parameter of the power function between malignant and benign lesions was observed (p-value = 0.025). We observed a greater separation in average lesion strain between malignant and benign lesions at large compression forces and demonstrated the characterization of this nonlinear effect using a power law model. Using this model, we were able to differentiate between malignant and benign breast lesions. With further development, the proposed method to utilize the nonlinear elastic response of breast tissue has the potential for improving non-invasive lesion characterization for potential malignancy.

Flexural Torsional Buckling of a Beam from the Dee Bridge of 1846 - Analytical and Finite Element Analyses

The Industrial Revolution in Victorian England was a period marked by rapid development of the machine industry, accompanied by new technologies in metallurgy and a need for transport between economic areas that was fast, cheap and convenient. This is a period when the railway transport arose and in a short time acquired an image familiar to us to this day. Passage of train sets across rivers and hard-to-reach areas requires transport facilities. In this period, an extremely large number of bridges and aqueducts were built, which have different constructive solutions, different technologies are applied and they are made of different materials, depending on the preference of their creator. This paper examines the collapse of one of the beams of the Dee Bridge on 24 May 1847. The analysis carried out shows the irrationality of the cross-sectional dimensions and types of girder supports witch generate large compressive forces in the beam, leading to flexural torsional buckling.

Study on non-linear analysis of arch bridges subjected to ground motion

Thanks to the cantilever launching technique, arch bridge building has once again become popular throughout the world. Today, these structures are one of the three main types of long-span bridges, along with suspension and cable-stayed bridges. Arch bridge structures have a complex behavior during powerful earthquakes because the arch rib is an element that is primarily susceptible to a large axial compression force brought on by dead loads. The nonlinear dynamic analysis of an arch bridge using STAAD Pro V8i software with earthquake loading is the subject of this research. Due to their easy load bearing qualities, arch bridges with short and medium spans are currently being constructed frequently for traffic bypass. Therefore, it is necessary to assess its stability in the event of a powerful earthquake. The STAAD-modeled arch bridge's nonlinear, time history analysis. The research in this study uses pro. For Time History analysis, data from the Bhuj Earthquake of 2001 is used, and the Rudramata Bridge, which collapsed during the Bhuj Earthquake, is researched. The primary focus of this study is on the analysis of the displacement, time-velocity, and time- acceleration responses of an arch bridge to lateral loads. And the results demonstrate that the displacement for the arch bridge is less than that for the Rudramata Bridge in all three directions.

Motivation to Decrease Discharge Cost Results in Improper Discharge of Regulated Medical Wastes from Small Clinics: Inspectional and Statistical Evidence in the Tokyo Metropolitan Area.

Regulated medical waste (RMW) management, particularly, improper discharges of RMW from small-scale medical institutions (less than 20 sickbeds), has drawn attentions. This study investigated improper discharges of RMW containers from small clinics to analyze improper discharge mechanisms. Inspectional survey categorized improper discharges into improper sealing, container deformation, overweight, container contamination, container damaging, etc. The inspection surveys were performed from April 2018 to March 2019. In total, 2364 containers were inspected, which was equivalent to 64317 Litters in container volume and around 13.19 Mg in weight. About 38% of RMW containers were categorized to improper discharges. They consist mainly of improper sealing (67.0%), container deformation (24.6%), and overweight (6.31%). It was hypothesized that frequent RMW discharges allow short interval of container discharge, which prevents clinic staff from human errors due to forgetting and might reduce improper discharges. However, the inspection results rejected this hypothesis. The survey proposes that improper discharges were likely not sporadic events, which possibly occurred in any clinics, but repeated events in certain clinics. It was also hypothesized that saving discharge cost likely induced overpacking of RMW to containers, particularly larger volume containers, and caused improper sealing, container deformation, and eventually overweight. The inspection results and statistical analyses validated this hypothesis. This study also validated one more hypothesis that large compressive force required for complete sealing might cause improper sealing. The measurement results rejected it. However, they also suggest that gender and age of clinic staff might be partially associated with improper sealing. Improper discharges of RMW containers seem to be non-random events. Specific clinics likely repeat improper discharges using larger volume containers. It is proposed that decreasing discharge cost induces overpacking of RMW to containers, and causes subsequent problems like container deformation.

A musculoskeletal simulation study on the biomechanics of the lower extremity during the golf swing

Purpose This study aimed to investigate the mechanisms of the human body dynamics during the golf swing through a musculoskeletal simulation for different types of subjects to better understand the biomechanical aspects of the golf sport. Methods The lower extremity model of the AnyBodyTM modeling system was adapted to a more advanced knee model to capture the large knee axial rotations during golf swing using an inverse dynamic musculoskeletal approach. Swings from three golfers, one with apparent osteoarthritis in both knee joints, one with bilateral total knee replacement, and one healthy, were captured in a motion capture laboratory and simulated. Results The golf swing generated a high axial rotation in the knee joint (approximately 25°-31°). Ball impact represented the most critical time event, near which maximum loading of the lower extremity was observed, e.g., knee compression force raised to a maximum of 329% body weight. The fast rate of knee loading by large compression forces prior to ball impact was identified as a potential cause of knee injury for golfers. Conclusions Our findings are comparable with previous experimental and computational studies, and the proposed musculoskeletal model can be employed to provide valuable information to clinicians and scientists, e.g., on the biomechanics of the lower extremities after total knee replacement for golf swing.

Behaviour of Concentrically Braced Steel Frames under Fire Loading

Knowing how a steel structure behaves under fire loading is of vital importance, given a large number of events in recent years have proved the vulnerability of steel structures under this type of hazard. Older concentrically braced frames have been widely used in buildings without observing seismic provisions and details. Although the vulnerability of this type of structural system, here referred to as non-seismic braced frames, has been studied under earthquake loading before, its behaviour under fire loading has not been investigated yet. This paper investigated the behaviour of global and local responses of the mentioned structural system under various uniform fire scenarios. The heating and cooling phases of fire were taken into account for different building stories using the finite element method. The results of analyses showed that the braces buckled at high temperatures due to the large compressive axial forces and expansion of lateral constraints. This phenomenon led to the early loss of lateral resistance of stories, which, in turn, resulted in the failure of columns. Consequently, the underlying floor collapsed under fire. The analysis results contribute to a better understanding of the behaviour of steel braced frames under fire conditions and the corresponding local and global responses.

Effects of Wheel Defects on Dynamic Track Buckling in Transition Zones of Open-Deck Steel Bridges

AbstractTrack buckling potential can be higher in the transition zones of steel bridges due to the combination of contact loads and large compressive forces present in this region because of rail a...

Numerical study of reinforced concrete coupled shear walls based on a two-dimensional finite element model

The reinforced concrete (RC) coupled shear wall is used extensively in high-rise buildings due to its extraordinary lateral resistance performance. Although massive individual RC shear wall as well as RC coupling beam specimens were tested, both the experimental and numerical studies on the seismic performance of RC coupled shear walls are insufficient. Considering the difficulties in large-scale coupled shear wall tests, finite element analysis (FEA) is carried out in this study to reveal quantitatively the effects of coupling beams with different aspect ratios and reinforcement layouts, as well as the behavior of coupling beams in the complex boundary conditions between adjacent wall piers. First, the finite element model based on a two-dimensional fixed crack constitutive model is proposed and validated by twelve coupling beam tests and the results demonstrate that buckling of diagonal bars should be reasonably considered. Then three coupled shear wall specimens are simulated, verifying the high accuracy of the proposed model. The effects of slabs on the coupled shear wall as well as coupling beams are also discussed. Finally, twenty coupled shear wall models with different degrees of coupling (DOCs) and diagonal bar ratios of coupling beams are analyzed. The results demonstrate that coupled shear walls with the diagonal bar ratio of 25–75% exhibit equivalent seismic performance with the diagonal bar ratio of 100%. In order to make full use of the energy dissipation of coupling beams, the DOC value should be no larger than 66%. With the constraint of adjacent wall piers, large axial compressive and tensile forces are induced, and their effects on the coupling beams should be considered.

Superconducting qubits in a flip-chip architecture

Flip-chip architectures have recently enabled significant scaling-up of multi-qubit circuits and have been used to assemble hybrid quantum systems that combine different substrates, for example, for quantum acoustics experiments. The standard flip-chip method uses superconducting galvanic connections between two substrates, typically implemented using sophisticated indium wafer-bonding systems, which give highly reliable and temperature-cyclable assemblies, but are expensive, somewhat inflexible in design, and require robust substrates that can sustain the large compressive forces required to cold-weld the indium bonds. A much simpler method is to assemble dies using very low-force contacts and air-dried adhesives, although this does not provide a galvanic contact between the dies. Here, we demonstrate that the latter technique can be used to reliably couple superconducting qubit circuits, in which the qubits are on separate dies, without the need for a galvanic connection. We demonstrate full vector qubit control of each qubit on each of the two dies, with high-fidelity single-shot readout, and further demonstrate entanglement-generating excitation swaps as well as benchmark a controlled-Z entangling gate between the two qubits on the two dies. This exemplifies a simple and inexpensive assembly method for two-plus-one-dimensional quantum circuit integration that supports the use of delicate or unusually shaped substrates.

Effects of screw pile installation on installation requirements and in-service performance using the discrete element method

Existing guidance on the installation of screw piles suggest that they should be installed in a pitch-matched manner to avoid disturbance to the soil that may have a detrimental effect on the in-service performance of the pile. Recent insights from centrifuge modelling have shown that installing screw piles in this way requires large vertical compressive (or crowd) forces, which is inconsistent with the common assumption that screw piles pull themselves into the ground requiring minimal vertical compressive force. In this paper, through the use of the discrete element method (DEM), the effects of advancement ratio, i.e., the ratio between the vertical displacement per rotation to the geometric pitch of the helix of the screw pile helix, on the installation resistance and in-service capacity of a screw pile is investigated. The findings are further used to assess the applicability of empirical torque capacity correlation factors for large diameter screw piles. The results of the investigation show that it is possible to reduce the required vertical compressive installation force by 96% by reducing the advancement ratio and that although over-flighting a screw pile can decrease the subsequent compressive capacity, it appears to increase the tensile capacity significantly.

Application of hybrid simulation method for seismic performance evaluation of RC coupling beams subjected to realistic boundary condition

SummaryIn a building subjected to seismic loading, large compressive force may develop in reinforced concrete (RC) coupling beams because of axial restraint imposed by the neighboring shear walls against the elongation of the coupling beams during the failure process. The axially compressive force can increase the shear stiffness and strength of the coupling beam and may change its failure mode. In this paper, a novel coupling beam testing procedure adopting hybrid simulation method is proposed in which the axial restraint is determined through hybrid simulation and the calculated axial restraint is imposed on a specimen during the test. RC coupling beams were tested by adopting both the proposed test procedure and the conventional testing approach in which the effect of the axial restraint is not accounted for. Test results depict a clear difference in the response of the coupling beam, such as shear capacity and failure mode, depending on the consideration of the axial restraint during the test. The test outcome demonstrates the usefulness and applicability of the proposed test procedure.

The effects of the surrounding viscoelastic media on the buckling behavior of single microfilament within the cell: A mechanical model

In the present study, a mechanical model is applied to account the effects of the surrounding viscoelastic media on the buckling behavior of single microfilament within the cell. The model immeasurably associates filament\'s bending rigidity, neighboring system elasticity, and cytosol viscosity with buckling wavelengths, buckling growth rates and buckling amplitudes of the filament. Cytoskeleton components in living cell bear large compressive force and are responsible in maintaining the cell shape. Actually these filaments are surrounded by viscoelastic media consisting of other filaments network and viscous cytosole within the cell. This surrounding, viscoelastic media affects the buckling behavior of these filaments when external force is applied on these filaments. The obtained results, indicate that the coupling of viscoelastic media with the viscous cytosol greatly affect the buckling behavior of microfilament. The buckling forces increased with the increase in the intensity of surrounding viscoelastic media.

Pseudo height anomaly over Indonesia in respect of GRACE gravity

This paper presents an overview of the recent height anomaly over Indonesia region in respect of Global Geopotential Model 2008 (EGM2008) which known as the most advance Global Geopotential Model. Recent height anomaly over Indonesia computed from Gravity Recovery and Climate Experiment (GRACE) satellite mission long term static solution using Bruns’ formula with degree and order up to 180. The results indicate that the deviation between geoid undulation with pseudo height anomaly deviation vary up to 12 meters with the largest deviations occur in several zones. Further investigation still needed to deduce the causes of the high height anomaly deviation that occur in several places in Borneo, Celebes and Papua, whether it is caused by a large compression forces or any other.

Thermomechanical modelling for the linear friction welding process of Ni-based superalloy and verification

This paper presents a fully coupled thermomechanical model for the linear friction welding process of Inconel-718 nickel-based superalloy by using the finite element method. Friction heat, plastic work, and contact formulation were taken into account for two deformable plastic bodies oscillating relative to each other under large compressive force. The modelling results of the thermal history at the weldline interface and thermal field at a distance away from the rubbing surfaces were compared to instrumented data sourced from related publications for model verification. Optimal linear friction welding process parameters were identified via comparison of weld temperature to the liquidus temperature of Inconel-718 alloy. Comparison of interface temperature showed a consistent range of values above the solidus melting temperature (1250 ℃) and below the liquidus melting temperature (1360 ℃) of Inconel-718 alloy. For the first time, a visible linear friction welding process window is identified using a thermomechanical computational modelling method. Through computational modelling, the influence of welding process parameters on the heat transfer and deformation of weld was systematically investigated.

Experimental Hybrid Testing of a Concrete Filled Steel Tube (CFST) Bridge Pier Subjected to Vertical and Horizontal Ground Motions

Hybrid simulation is a form of advanced testing that combines both numerical and experimental techniques to achieve an economical seismic response assessment of structures. The technique utilises the best feature of computer simulations and combines these with experimental testing. This makes hybrid simulation a powerful platform for experimentally studying the seismic responses of structures to collapse. This paper presents an application of hybrid simulation for tracing the seismic responses of a concrete filled steel tube (CFST) column subjected to combined horizontal and vertical ground accelerations. A state-of-the-art testing facility, known as the multi axis substructure testing (MAST) system, was used to impose complex boundary effects on the physical specimen using mixed load and deformation modes. The column was subjected to five increasing ground motion levels. During the test, the column experienced large axial force variations of up to 2.2 MN and reached a maximum drift of 8.8% without significant damage. The results demonstrate that this CFST column is thus capable of resisting large compression and tension forces, offering high levels of ductility without collapse.

Effect of the Microstructure on the Wear Resistance of a Pearlitic Steel

Abstract Despite the experimentation of bainitic and martensitic microstructures in wheel-rail steels, pearlitic microstructure remains dominant in railway track. The wear resistance behavior of bainitic and pearlitic microstructures is still a matter of controversy. In this study, pin-on-disc sliding wear tests were performed to analyze the effects of the microstructure on wear resistance. The AISI 1080 steel was isothermally treated at five temperatures using a dilatometer in order to obtain pearlite, bainite and martensite structures. After these treatments, bainitic and martensitic samples were tempered at 500°C. It was possible to achieve pearlitic specimens with interlamellar spacing ranging from 70 ± 4 nm to 243 ± 9 nm. It was found that the wear resistance increases with decreasing the interlamellar spacing, fine pearlite showed 30% lower mass loss than coarse pearlite. The severe deformation and dislocation accumulation in different depth from the contact surface were analyzed by electron backscattered diffraction technique. The results showed that the first 10 µm depth from the contact surface was severely deformed and a high number of random high-angle boundaries developed due to the large compressive force. Fine pearlitic structure tends to present a better wear performance when compared to bainitic or martensitic structures.

Relationship Between Insertion Torque and Compression Strength in the Reverse Total Shoulder Arthroplasty Baseplate.

Reverse shoulder arthroplasty is a well-established procedure, however, there is limited data in the literature regarding adequate insertion torque and the resulting compression for glenoid baseplate fixation. In this biomechanical study, we evaluated the relationship between insertion torque and baseplate compression by simultaneously measuring the insertion torque and axial compressive forces generated by two reverse shoulder arthroplasty baseplates with central screw design. Three different bone surrogates were chosen to mimic clinical scenarios where differences in compression achieved during baseplate insertion may exist due to varying bone quality. Epoxy resin sheets were combined with the bone surrogates to simulate the glenoid vault. A digital torque gauge was used to measure insertion torque applied to the baseplate, while compression data were collected continuously from a load cell. A strong positive correlation was found between baseplate compression and insertion torque. Among the lower density bone surrogates, neither baseplate design reached maximum insertion torque (6.8 Nm) due to material strip-out. This phenomenon did not occur in denser bone surrogates. Both baseplate designs experienced a significant increase in mean baseplate compression as insertion torque increased and were found to behave similar in the denser bone surrogates. The results presented here suggest that larger compressive forces can be achieved with an increase in insertion torque in denser bone surrogates, but caution must be used when trying to achieve fixation in poor-quality bone. Clinically, this could be useful preoperatively to minimize baseplate failure, and in further studies regarding baseplate design for improved initial fixation and stability. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 38:871-879, 2020.