Experimental Study on the Crushing Properties of Corn Stalks in Square Bales

With the development of straw baling mechanization technology, straw is stored in the form of square baling or round baling. At present, hammer mill or the guilt-cutting and rubbing combined mill is widely used to crush square bales of straw. These two kinds of crushing equipment have disadvantages such as low productivity, large power consumption, and poor crushing effect. This paper aims to study and analyze the crushing characteristics of square baled straw after unbaling, and lay a theoretical foundation for the later research and development of a special square baled straw crusher with high productivity, low power consumption, good crushing effect, and the simulation of the square baled corn straw crushing process. For this purpose, this study carried out a corn bale crushing experiment on the Instron 8801 fatigue test machine, and studied the effects of blade angle, water content and loading speed on corn bale crushing force through the response surface method. Test results showed that the crushing process includes the compression stage and shearing stage; in terms of single factor effect, with the increase in water content and blade angle, the crushing force of the corn bale increased, but the loading speed had no significant effect on the crushing force of the corn bale. In terms of interaction effect, there was interaction effect between moisture content and blade inclination angle, when moisture content was 10%, with the increase in blade inclination angle, the incremental speed of the crushing force also increased gradually. When the blade inclination angle was 10°, with the increase in moisture content, the incremental speed of the crushing force also increased, and the interaction effect of them jointly acted on the crushing force of the corn bales.

Autonomous Instrumentation for Measuring Electromagnetic Radiation from Rocks in Mine Conditions—A Functional Analysis

This paper analyses the function of an innovative integrated receiver for the measurement of electromagnetic field emissions. The autonomous receiver measures and registers the elevated emission levels of both components of the EM field originating from rocks subjected to increased mechanical stress. The receiver’s sensitivity of 60 µV/m, its dynamic range of 98 dB, and its impulse response of 0.23 V/µs were determined in laboratory conditions. Real EM field signals from hard coal samples subjected to crushing force were recorded using an autonomous receiver. The observed and recorded results confirm that the receiver operates in the full range of amplitudes of the EM field signal emitted from the rock. The results determine the band of characteristic signals for EM field emission from hard coal. The system created on the basis of autonomous EM receivers can support the existing seismic safety systems in real mine conditions by predicting the possibility of mine collapse hazards.

Finite Element Modelling Approach for Progressive Crushing of Composite Tubular Absorbers in LS-DYNA: Review and Findings

Robust finite element models are utilised for their ability to predict simple to complex mechanical behaviour under certain conditions at a very low cost compared to experimental studies, as this reduces the need for physical prototypes while allowing for the optimisation of components. In this paper, various parameters in finite element techniques were reviewed to simulate the crushing behaviour of glass/epoxy tubes with different material models, mesh sizes, failure trigger mechanisms, element formulation, contact definitions, single and various numbers of shells and delamination modelling. Six different modelling approaches, namely, a single-layer approach and a multi-layer approach, were employed with 2, 3, 4, 6, and 12 shells. In experimental studies, 12 plies were used to fabricate a 3 mm wall thickness GFRP specimen, and the numerical results were compared with experimental data. This was achieved by carefully calibrating the values of certain parameters used in defining the above parameters to predict the behaviour and energy absorption response of the finite element model against initial failure peak load (stiffness) and the mean crushing force. In each case, the results were compared with each other, including experimental and computational costs. The decision was made from an engineering point of view, which means compromising accuracy for computational efficiency. The aim is to develop an FEM that can predict energy absorption capability with a higher level of accuracy, around 5% error, than the experimental studies.

Fabrication of Ni-NiO Foams by Powder Metallurgy Technique and Study of Bulk Crushing Strength

Despite the importance of Nickel Oxide (NiO) in diverse functional applications, very little information is available on the mechanical properties of bulk or porous NiO or, mostly unnoticed. In this study, porous Ni-NiO foam was synthesized using space holding-powder metallurgy and sintering methods to produce opened-cell structure with macrogravel and Neolamarckia cadamba (Cadamba flower) like surface morphology. Four different types of porous Ni-NiO with different pore diameter of 35.65 ± 12.77, 36.10 ± 8.85, 68.20 ±7.36 and 62.45 ± 17.48 µm were fabricated for evaluating the effect of porosity on the mechanical properties of bulk porous Ni-NiO foam. The mechanical properties such as bulk crushing force of as synthesized Ni-NiO foam with various porosities such as 20.55, 27.35, 27.85 and 28.82 % exhibited the average crushing load of 115.40, 39.95, 138.10 and 151.20 N, respectively. This study suggests that crushing load of Ni-NiO foam is not only depending on the porosity but also on the sintering temperature and crystallite sizes of NiO. HIGHLIGHTS Ni-NiO foam is synthesized using space holding-powder metallurgy and sintering methods Different pore diameter is fabricated for evaluating the effect of porosity on the mechanical properties of bulk porous Ni-NiO foam Crushing strength of Ni-NiO foam is not only depending on the porosity but also on the sintering temperature and crystallite sizes of NiO GRAPHICAL ABSTRACT

New source material for improving raspberry assortment in the Central region of Russia

The aim of the research is to search new sources of the main economically valuable traits for further breeding of raspberry. Nineteen previously created selected forms were studied for winter resistance components under controlled conditions, for resistance to major fungal diseases, productivity components, strength and biochemical composition of fruits. The zoned Gusar variety was used as the control. The work was carried out in 2018-2020 according to generally accepted techniques. Artificial freezing of raspberry stems was carried out in the climate chamber TH-6 JEIO TECH. According to the results of the studies, selected forms 8-10х-1, 6-125-4, which have an increased resistance to certain components of winter resistance, have been identified. Hybrids 2-115-1 and 1-188-1 have cumulative resistance to winter damage factors. Based on the integrated resistance of raspberry hybrids to the main fungal diseases, new sources have been revealed: forms 1-124-1, 2-115-1, 2-115-2, 1-111-21, 1-8-2, 2-35-1, 2-90-3, 6-125-4, 3-4-2, 8-10х-1, 4-33-21 and 4-122-2. The degree of their damage did not have a significant influence on winter hardiness, productivity and quality of berries. As the result of study of components of the raspberry productivity, selected forms (1-111-21, 2-90-2 and 2-90-3), forming fruits with an average weight of more than 4.0 g, and genotypes with large and one-dimensional fruits (1-176-21, 2-35-1, 4-33-21, 1-124-1) not growing smaller from picking to picking were identified. The highest potential productivity was noted for selections 2-115-1, 1-111-21, 1-188-1, 4-46-2, 2-90-2 and 2-90-3, capable to form a yield of more than 1.3 kg per bush. The selections 1-124-1, 2-90-2 and 2-90-3 are distinguished by an increased strength of the fruits. They form fruits with a crushing force exceeding 5.0 N, which ensures the safety of integrity and transportability when manually harvested. No complex sources of increased accumulation of biologically active substances have been identified. Genotypes with a high content of individual biochemical substances were selected. The highest accumulation of soluble solids and sugars was noted in the samples 2-90-3, 18-11-4 and 2-115-1. Highest accumulation o the vitamin C was observed in the samples 6-125-4 (59.8 mg/100 g) and 2-90-3 (61.5 mg/100 g). As new sources in breeding to improve the taste characteristics of raspberry, it is necessary to use selected forms 2-90-2, 2-115-1 and 6-125-4, approaching in taste to the standard variety Novost Kuzmina. Selected forms 2-90-2, 2-90-3 and 2-115-1 are new sources in raspberry breeding, combining a complex of economically valuable traits at a high level.

Numerical Optimization for the Impact Performance of a Rubber Ring Buffer of a Train Coupler

Shock and vibration caused by mechanical motion bring huge potential threats to the service life and assembly reliability of mechanical systems. Rubber materials have been widely used in aircraft, trains, and other engineering fields, due to their excellent properties in shock and vibration absorption. This paper aimed to study the rubber ring buffer applied to a certain type of Chinese locomotive. Firstly, the finite element model was established and verified through experimental data. Based on the verified simulation model, the influence of the constitutive parameters (C01/C10 ratio height H and contour radius R) of the rubber ring on its energy absorption and peak crushing force under impact loading was studied in a numerical environment. Finally, the design of the experiment was carried out by the optimized Latin hypercube method, and the response surface model was established, which intuitively demonstrated the influence of the relevant parameters of the rubber ring on the change trend of the energy absorption and peak force. Based on the proxy model, the parameters that improve the crashworthiness of the rubber ring buffer were found quickly by the NSGA-II optimization algorithm, and the problems of a long calculation time and low optimization efficiency when using the conventional finite element method were avoided. The optimization results stated that when H = 107.57 mm and R = 85.70 mm, C01/C10 = 0.0571 of the energy absorption of the optimized buffer was increased by 59.03%, and the peak force was decreased by 14.37%, compared with the original structure. The optimized rubber ring buffer is expected to reduce the peak crushing force, enhance the energy absorption capacity, and mitigate the damage to the train system caused by shock and vibration.

Energy Absorption Performance of Bio-inspired Honeycombs: Numerical and Theoretical Analysis

Energy absorption performance has been a long-pursued research topic in designing desired materials and structures subject to external dynamic loading. Inspired by natural bio-structures, herein, we develop both numerical and theoretical models to analyze the energy absorption behaviors of Weaire, Floret, and Kagome-shaped thin-walled structures. We demonstrate that these bio-inspired structures possess superior energy absorption capabilities compared to the traditional thin-walled structures, with the specific energy absorption about 44% higher than the traditional honeycomb. The developed mechanical model captures the fundamental characteristics of the bio-inspired honeycomb, and the mean crushing force in all three structures is accurately predicted. Results indicate that although the basic energy absorption and deformation mode remain the same, varied geometry design and the corresponding material distribution can further boost the energy absorption of the structure, providing a much broader design space for the next-generation impact energy absorption structures and systems.

A Numerical and Experimental Study on the Energy Absorption Characteristics of Deployable Origami Tubes

Energy absorption devices are widely used to mitigate damage from collisions and impact loads. Due to the inherent uncertainty of possible impact characteristics, passive energy absorbers with fixed mechanical properties are not capable of serving in versatile application scenarios. Here, we explore a deployable design concept where origami tubes can extend, lock, and are intended to absorb energy through crushing (buckling and plasticity). This system concept is unique because origami deployment can increase the crushing distance between two impacting bodies and can tune the energy absorption characteristics. We show that the stiffness, peak crushing force, and total energy absorption of the origami tubes all increase with the deployed state. We present numerical and experimental studies that investigate these tunable behaviors under both static and dynamic scenarios. The energy-absorbing performance of the deployed origami tubes is slightly better than conventional prismatic tubes in terms of total absorbed energy and peak force. When the origami tubes are only partially deployed, they exhibit a nearly-elastic collapse behavior, however, when they are locked in a more deployed configuration they can experience non-recoverable crushing with higher energy absorption. Parametric studies reveal that the geometric design of the tube can control the nonlinear relationship between energy absorption and deployment. This concept for deployable energy-absorbing origami tubes can enable future protective systems with on-demand properties for different impact scenarios.

Energy absorption characteristics of thin-walled steel tube filled with paper scraps

The specific energy absorption of a thin-walled tube can be improved by filler. This study examined the potential use of a cheaper biomass filler, paper scraps, to enhance the energy absorption characteristics of the structure while reducing its cost, compared to that with a traditional filler such as foam material. Quasi-static crushing tests and finite element simulations were performed by using the explicit non-linear finite element software LS-DYNA to determine the improvements to the mean crushing force and specific energy absorption of the steel tube when filled with different densities of paper scraps. The mean crushing force and specific energy absorption of the empty tube, the paper scraps, and thin-walled tube filled with paper scraps were determined, and corresponding numerical simulations were performed. The simulation and test results showed that the impact performance of tube filled with paper scraps was greatly improved when paper scraps density was 0.35 g/cm3. By optimizing paper scraps filling structure, a new structure that could further enhance the specific energy absorption was obtained. The optimal scheme could increase the specific energy absorption of Q345 steel tube by 11.35%.