Force-deformation Curves Research Articles

A Quantitative Study of Axial Performance of Rockbolts with an Elastic–Debonding Model

Full-length anchorage rockbolts are widely used in roadway reinforcement and rock controlling in underground mining. This article proposes using an elastic–debonding (ED) model to analyse the axial performance of rockbolts. The advantage of this ED model was that the full force–deformation curve of rockbolts comprised only three phases, which was relatively simpler to calculate. Its effectiveness was compared with experiment tests. Based on the ED model, a series of parameter studies was conducted. Results showed that for cross-section area of rock, there was a critical range. Once the cross-section area of rock was beyond that critical range, external rock had a mild impact on the axial performance of rockbolts. Rockbolt diameter significantly affected the axial performance of rockbolts. When rock diameter increased, the peak force of rockbolts increased linearly, while deformation at the peak force decreased non-linearly. The corresponding calculation equation between the peak force, deformation at the peak force, and rockbolt diameter was obtained. Borehole diameter had a mild impact on the axial performance of rockbolts. Increasing rockbolt length benefits improving the peak force of rockbolts. Rockbolt modulus of elasticity had a more apparent impact on the deformation at peak force. Mechanical properties of the bolt/grout (b/g) face affected the axial performance of rockbolts. Increasing the b/g face strength improved the peak force of rockbolts. Slippage at the ultimate load had a more apparent impact on the turning point between the elastic phase and the elastic–softening phase.

Studying Impact of Moisture, Node Position and Loading Rate of Paddy Straw on its Mechanical Properties

In this study, mechanical properties of paddy straw such as bending strength, shear strength and Young's modulus were determined through force-deformation curve using textural analyzer with 50 kg load cell. The mechanical properties were determined at three moisture contents, i.e., 18.4% (M1), 13.5% (M2) and 10.8% (M3), at three node positions, i.e., N1, N2 and N3 and three loading rates, i.e., 25, 30 and 35 mm min-1, respectively. The results revealed that moisture content and loading rate at different node positions significantly (p<0.01) affected the bending strength, shear strength, and Young's modulus of straw, whose values varied from 5.35 to 17.34 MPa, 4.99 to 7.35 MPa, 0.43 to 1.39 GPa, respectively, through N1 to N3 with decrease in moisture content; likewise, other findings also indicated increase in output values on increasing loads through N1 to N3. Cutting force was also significantly affected (p<0.01) by shear angle and moisture content, which varied from 6.39 to 22.9 N, and cutting energy ranged from 142 to 511 J by Straw Management System serrated blade and was found to be minimum at 20° shear angle. The mechanical property of the straw for residue management in the context of cutting force for node position N3 at the initial moisture content was found optimum.

On the suitability of additively manufactured gyroid structures and their potential use as intervertebral disk replacement - a feasibility study.

Intervertebral disk degeneration is a growing problem in our society. The degeneration of the intervertebral disk leads to back pain and in some cases to a herniated disk. Advanced disk degeneration can be treated surgically with either a vertebral body fusion or a disk prosthesis. Vertebral body fusion is currently considered the gold standard of surgical therapy and is clearly superior to disk prosthesis based on the number of cases. The aim of this work was the 3D printing of Gyroid structures and the determination of their mechanical properties in a biomechanical feasibility study for possible use as an intervertebral disc prosthesis. Creo Parametric 6.0.6.0 was used to create models with various Gyroid properties. These were printed with the Original Prusa i3 MK3s+. Different flexible filaments (TPU FlexHard and TPU FlexMed, extrudr, Lauterach, Austria) were used to investigate the effects of the filament on the printing results and mechanical properties of the models. Characterization was carried out by means of microscopy and tension/compression testing on the universal testing machine. The 3D prints with the FlexHard and FlexMid filament went without any problems. No printing errors were detected in the microscopy. The mechanical confined compression test resulted in force-deformation curves of the individual printed models. This showed that changing the Gyroid properties (increasing the wall thickness or density of the Gyroid) leads to changes in the force-deformation curves and thus to the mechanical properties. The flexible filaments used in this work showed good print quality after the printing parameters were adjusted. The mechanical properties of the discs were also promising. The parameters Gyroid volume, wall thickness of the Gyroid and the outer wall played a decisive role for both FlexMed and FlexHard. All in all, the Gyroid structured discs (Ø 50mm) made of TPU represent a promising approach with regard to intervertebral disc replacement. We would like to continue to pursue this approach in the future.

An Assessment of Some Mechanical Properties of Harvested Potato Tubers cv. Spunta

Mechanical properties of vegetables or crop materials play a noteworthy part in designing new related implements. These properties can be extracted from force–deformation curves. Several factors, such as soil preparation, irrigation, and pre- and post-harvest treatments influence them. The core objective of this investigation work was to analyze force–deformation curves obtained from compression, penetration, and shear tests of potatoes (Spunta cv.) produced with three tillage implements. The potatoes cv. Spunta were cultivated in loamy sand soil under the center-pivot irrigation system. The tillage implements used were a disc harrow plow, chisel plow, and moldboard plow. The trials were performed at a constant planting depth (15 cm) below the soil and a single plowing speed of 5.4 km/h. All data were expressed as an average of five replicates ± standard deviation. The force–deformation curves analysis showed that the modulus of elasticity for potatoes cv. Spunta ranged from 4.32 to 5.8 N/mm, the bioyield force ranged from 84.25 to 114.12 N, and rupture forces ranged from 100.90 to 139.78 N. Furthermore, the results showed that the average values of the elastic and plastic ranges were 3.0 and 2.1 mm, respectively. The mean value of hardness was 1671.53 N·mm. No significant differences were observed with respect to the two planting seasons, but tillage implements had a significant impact on the characteristics extracted from the compression tests. The mean of the maximum forces required to penetrate the potato during the penetration stage were 41.24 N, 44.86 N, and 47.16 N for potatoes produced with the disc harrow plow, chisel plow, and moldboard plow, respectively. Similarly, the means of the maximum forces required to cut the potato in the shear stage were 724.38 N, 761 N, and 773.43 N for the disc harrow plow, chisel plow, and moldboard plow, respectively. The force–deformation curves showed that additional information might be required to obtain a complete description of the potato quality necessary to harvest potatoes cv. Spunta using harvesting and handling equipment with reduced economic loss. An extensive study of the soil characteristics and the above-mentioned properties is also recommended. The results obtained about the mechanical characteristics of potatoes cv. Spunta can be useful in providing information that aids in designing potato harvesting machines and in potato products factories.

Improving the lateral load resistance capacity of cellular lightweight concrete (CLC) block masonry walls through ferrocement overlay

Cellular lightweight concrete (CLC) block masonry is an eco-friendly building material gaining popularity in both developed and developing countries. Despite its increasing use, the material's behavior under seismic loading remains insufficiently understood. This research involved quasi-static testing of two full-scale CLC blocks masonry walls strengthened with ferrocement overlay. One of the strengthened walls was subjected to confinement, while the other was unconfined. The aim was to assess their seismic performance by comparing force deformation curves, damping, stiffness degradation, and structural performance levels with non-strengthened walls. The findings indicate that the strengthened masonry outperformed the unreinforced version, suggesting that CLC block masonry exhibits potential for effective performance in low to moderate seismic zones.

An efficient nonlinear hybrid model of energy dissipation piers utilizing fiber beam and self-developed hysteretic spring elements

Energy dissipation piers comprised of concrete filled steel tubular (CFST) columns and steel shear links can exhibit good seismic performance by reasonable collaborative optimization design of columns and links. Considering the time and economic costs of experiments and fine element analysis (FEA), an efficient and accurate numerical model is critical to investigate the hysteretic behavior of energy dissipation piers under earthquake action. Therefore, a hysteretic constitutive law for steel shear links is first proposed including the theoretical shear force-deformation skeleton curve and the unloading and reloading rules during hysteretic loading. Next, a hysteretic spring model is developed for efficiently simulating the hysteretic mechanical behavior of steel shear links, which is validated to have good accuracy with comparison to fine FEA and experimental results. Then, a simplified hybrid model consisting of the self-developed spring model and fiber beam model and two multi-scale FEA models with different levels of refinement are established for nonlinear analysis of energy dissipation piers, respectively. The comparison of numerical and test results confirms that the innovative fiber beam-spring hybrid model can accurately describe the hysteretic performance of energy dissipation piers, especially the detailed mechanical behavior of steel shear links and column feet, which provides an efficient numerical tool for analysing the collaborative working mechanism of energy dissipation piers and similar energy dissipation structures.

Increasing design flexibility by manually adapting the solution space for crashworthiness

The solution space methodology, as presented in 2013, was meant to guide developers at the very beginning of the development process of a new mechanically crashworthy car. Several attempts were already made to use this methodology at later development stages. However, they all encountered problems related to its very strict and demanding corridors, thus constricting the design parameters. To allow more flexibility, two different approaches were proposed to relax the initial strict conditions. The first introduced temporal dependencies to widen the corridors. The second locally changed the corridors to adapt to the needs of the development, introducing dependencies between components. We, on the contrary, propose a new method to increase flexibility without introducing any kind of dependencies. We manage this by computing the intervals of solution space under user-defined conditions, hence selecting a custom set of independent corridors that fits the data gathered during development; i.e.: force-deformation curves that can be measured during a drop-tower test simulation. This new methodology of the adaptive solution space allows designers to edit the corridors, in order to have more flexibility for fulfilling high-level requirements when independently designing new components.

Biyo-Hibrit Çarpışma Kutusu Tasarımının Sayısal Analizi ve Eğik Darbe Altında Enerji Sönümleme Performanslarının İncelenmesi

Designs inspired by nature are used in several areas as automotive, aerospace and defence industry. In studies on the axial crushing analysis of thin-walled structures such as crashworthiness, a critical role of developments of design aspects have been achieved by the bioinspired perspective. The energy absorption performance of the crashworthiness which shapes the basis of the crushing analysis is the main aspects of the numerical and experimental solution methods. In order to verification of finite element model, the energy absorption characteristic specifications were performed the square tube under axial loads. Using the proposed of lotus-inspired design performances of axial load condition, the newly design was prepared square tube included lotus bifurcation as called "bio-hybrid". To compare the axial and oblique loads performances of the L (lotus) and BH (bio-hybrid) structures, force-deformation curves was evaluated with characteristic properties as EA, CFE, SEA, MCF and PCF. The numerical analysis showed that the square outer frame included lotus bifurcation of crashworthiness is less suitable than natural circular lotus configuration under oblique loads. However, the lotus-inspired configuration is advantageous under axial loads

Instrumental mechanical parameters related to hand-feel touch firmness of blueberries

Hand-feel touch firmness is a sensory method reported to be used by the blueberry industry to characterise individual fruit firmness quality. A ‘soft’ blueberry may be considered unmarketable. However, firmness assessed by a hand touch is questionable due to being highly influenced by the assessor's subjective judgment. Objective instrumental methods are preferred to measure firmness and create a reliable and consistent dataset. This research aimed to study the relationship between sensory hand-feel touch firmness measured by a trained sensory panel and instrumental mechanical parameters of blueberry ‘Centurion’. To our knowledge, this is the first attempt to relate instrumental mechanical parameters to hand firmness using a sensory panel setting and reference samples to exemplify hand-feel intensity differences. Seven assessors were trained to evaluate hand touch firmness in a sensory panel setting. References samples resembling a blueberry were made of silicone and used to calibrate assessors’ performance by exemplifying four blueberry firmness scores (‘very soft’, ‘soft’, ‘firm’ and ‘very firm’). Six sensory sessions were conducted, where each session represented a harvest date and storage time combination (3 harvest dates X 2 storage times). Each sensory session considered blueberries exposed to five storage relative humidity (71 %, 88 %, 95 %, 97 % and 100 % RH). As a result, assessors were able to discriminate differences in hand touch firmness as influenced by storage relative humidity (water loss differences). In addition, mechanical parameters measured by the slope of force-deformation curve using a plate probe on a compression test (hardness slope) or a needle probe on a penetration test (skin break slope) were best related to sensory hand-feel firmness. Average hardness slope and skin break slope higher than 1.7 kN m−1 and 0.42 kN m−1, respectively, were associated with a very low (≤5 %) likelihood of observing unmarketable (‘soft’ + ‘very soft’) 'Centurion' blueberries in a batch. Our study provides a basis for the standardisation of mechanical methods that can be used to assess blueberry quality based on its ability to represent consumer sensation preferences of texture.

Effect of alumina nano‐particles on collapse behavior and energy absorption of laterally loaded glass/epoxy composite tubes

AbstractDue to its exceptional mechanical and crashworthiness properties, lightweight nanocomposites have recently been used more and more in aviation, defense, nautical, and automotive applications. Nanocomposite cylinders could be effectively employed in this respect as energy‐absorbing components for decreasing the impact energy during vehicle crashes. The current work examined the crashworthiness response of nano‐alumina (Al2O3) filled glass fiber reinforced epoxy (GFRE) composite tubes using quasi‐static lateral compressive loads. Crushing profiles and crush force–deformation curves of all representative samples were recorded and discussed. The total absorbed energy (AE) and specific absorbed energy (SEA) for tested specimens were assessed. Furthermore, a multi‐attribute decision making (MADM) technique known as complex proportional assessment (COPRAS) was used to compute the optimum nano‐Al2O3 wt%. Based on the experimental results, the addition of 1, 2, and 3 wt% of nano‐Al2O3 enhanced AE by 7.69%, 18.14%, and 51.21% and SEA by 3.43%, 13.98%, and 39.84%, respectively. While deteriorations of 6.59% and 17.41% in AE and SEA, respectively, were recorded with the addition of 4 wt% of nano‐Al2O3. Overall findings showed that (GFRE) composite tubes with 3 wt% of nano‐Al2O3 have a special potential to absorb energy.Highlights The designed tubes, that is, GFRE tubes filled with 0, 1, 2, 3, and 4 wt% of nano‐alumina (Al2O3) were created using wet‐wrapping by hand lay‐up technique. The fabricated tubes were subjected to lateral compression loads to investigate their crashworthiness behavior. The crashing load and absorbed energy versus displacement responses for the laterally loaded tubes were exposed. The histories of deformation were also examined. Complex proportional assessment (COPRAS) was used to find the optimum nano‐Al2O3 wt%.

Mechanical fatigue testing in silico: Dynamic evolution of material properties of nanoscale biological particles

Biological particles have evolved to possess mechanical characteristics necessary to carry out their functions. We developed a computational approach to "fatigue testing in silico", in which constant-amplitude cyclic loading is applied to a particle to explore its mechanobiology. We used this approach to describe dynamic evolution of nanomaterial properties and low-cycle fatigue in the thin spherical encapsulin shell, thick spherical Cowpea Chlorotic Mottle Virus (CCMV) capsid, and thick cylindrical microtubule (MT) fragment over 20 cycles of deformation. Changing structures and force-deformation curves enabled us to describe their damage-dependent biomechanics (strength, deformability, stiffness), thermodynamics (released and dissipated energies, enthalpy, and entropy) and material properties (toughness). Thick CCMV and MT particles experience material fatigue due to slow recovery and damage accumulation over 3-5 loading cycles; thin encapsulin shells show little fatigue due to rapid remodeling and limited damage. The results obtained challenge the existing paradigm: damage in biological particles is partially reversible owing to particle's partial recovery; fatigue crack may or may not grow with each loading cycle and may heal; and particles adapt to deformation amplitude and frequency to minimize the energy dissipated. Using crack size to quantitate damage is problematic as several cracks might form simultaneously in a particle. Dynamic evolution of strength, deformability, and stiffness, can be predicted by analyzing the cycle number (N) dependent damage, [Formula: see text] , where α is a power law and Nf is fatigue life. Fatigue testing in silico can now be used to explore damage-induced changes in the material properties of other biological particles. STATEMENT OF SIGNIFICANCE: Biological particles possess mechanical characteristics necessary to perform their functions. We developed "fatigue testing in silico" approach, which employes Langevin Dynamics simulations of constant-amplitude cyclic loading of nanoscale biological particles, to explore dynamic evolution of the mechanical, energetic, and material properties of the thin and thick spherical particles of encapsulin and Cowpea Chlorotic Mottle Virus, and the microtubule filament fragment. Our study of damage growth and fatigue development challenge the existing paradigm. Damage in biological particles is partially reversible as fatigue crack might heal with each loading cycle. Particles adapt to deformation amplitude and frequency to minimize energy dissipation. The evolution of strength, deformability, and stiffness, can be accurately predicted by analyzing the damage growth in particle structure.

Experimental assessment of retrofitted damaged mortarless dry stacked interlocking masonry walls

The aim of this research study is to experimentally investigate the effectiveness of ferrocement overlay on the seismic capacity of damaged mortarless dry stacked masonry constructed with self-interlocking compressed earth blocks. For the achievement of the aim, two full scale damaged walls were retrofitted with ferrocement overlay technique. To study the effects of openings, one wall was provided with a window, while the other one was a solid wall. Retrofitting materials consist of 18-gauge galvanized steel welded wire mesh having opening size of 12.5 × 12.5 mm (0.5" × 0.5″) and 1:4 conventional cement-sand mortar. The walls were tested with displacement-controlled quasi static cyclic loading protocols. The seismic performance of the retrofitted walls under a combination of vertical axial load and lateral reverse cyclic loading was compared to the specimens before retrofitting. Damage patterns and different seismic parameters such as force deformation curve, energy dissipation, stiffness degradation and performance levels were assessed. The results show that the seismic capacity of damaged mortarless dry stacked interlocking masonry can be restored and enhanced as the overall response of the structure is significantly improved.

Seismic performance of bidirectional bolted drilled cut RBS-CFT connections under cyclic loads

Welded connections were widely used in different regions of the world for ease of fabrication and good performance under gravity load. However, Northridge (1994) and Kobe (1995) earthquakes demonstrated that seismic performance of welded connections has been inferior as compared to that of bolted connections. Reduced beam section (RBS) has been one of the effective methods to enhance seismic performance in terms of energy dissipation capacity and ductility. Drilled-cut RBS-CFT connections have been gaining acceptance for enhancing overall seismic performance of steel moment resisting frames. However, no comparative study has been reported in the literature on RBS-CFT connection with bidirectional bolts for evaluation of their seismic performance. In view of the above, experimental study has been carried out for evaluation of seismic performance of two variants of RBS-CFT connections with constant drilled cut (CD-cut) and varied drilled cut (VD-cut) RBS. Both the drilled cut RBS-CFT connections are found to be semi-rigid in nature and exhibited stable hysteretic behavior. Test results showed that the cumulative energy dissipation capacity in the VD-cut connections is marginally higher than CD-cut connection. VD-cut RBS-CFT connections effectively reduced the lateral-torsional deformation. The load-carrying capacity and stiffness degradation ratio of VD-cut RBS-CFT connection is higher than CD-cut RBS-CFT connection. Damping of the both connections are nearly of similar order. Recorded strain data of both connections showed that plastic hinge confined only on drilled zone of the beam. Further, a detailed numerical simulation of force-deformation envelope curve of RBS-CFT connections was carried out using ABAQUS software. Simulated force-deformation envelope curves are found to be in close agreement with those obtained from experimental investigation. Both connections meet the seismic requirements of the AISC specified for composite special moment-resisting frames (SMRFs) by achieving rotational capacity of 0.04 radians without any damage in the joint panel region.

Seismic performance evaluation of plastered cellular lightweight concrete (CLC) block masonry walls

The current research presents a novel and sustainable load-bearing system utilizing cellular lightweight concrete block masonry walls. These blocks, known for their eco-friendly properties and increasing popularity in the construction industry, have been studied extensively for their physical and mechanical characteristics. However, this study aims to expand upon previous research by examining the seismic performance of these walls in a seismically active region, where cellular lightweight concrete block usage is emerging. The study includes the construction and testing of multiple masonry prisms, wallets, and full-scale walls using a quasi-static reverse cyclic loading protocol. The behavior of the walls is analyzed and compared in terms of various parameters such as force–deformation curve, energy dissipation, stiffness degradation, deformation ductility factor, response modification factor, and seismic performance levels, as well as rocking, in-plane sliding, and out-of-plane movement. The results indicate that the use of confining elements significantly improves the lateral load capacity, elastic stiffness, and displacement ductility factor of the confined masonry wall in comparison to an unreinforced masonry wall by 102%, 66.67%, and 5.3%, respectively. Overall, the study concludes that the inclusion of confining elements enhances the seismic performance of the confined masonry wall under lateral loading.

Experimental and numerical investigation on the deformation behaviors of large diameter steel tubes under concentrated lateral impact loads

Large diameter steel tubes are widely used in bottom fixed and floating offshore wind turbines. Offshore wind turbines (OWTs) operating in the oceans are exposed to the risk of collisions when ships pass and dock at turbines. Thus, it is extremely important to investigate the impact mechanics of ship-OWT collisions and propose practical designs for methods to protect OWTs from collision loads. This paper presents a series of experimental and numerical studies on the deformation behaviors of large diameter steel tubes from a NREL 5 MW spar-type floating offshore wind turbine (FOWT) under lateral impact loads. These studies consider the effects of different impact velocities, attached masses, diameters and thicknesses of the tubes on their response to impact loading. In these experiments, a rigid indenter was mounted on a pendulum system and accelerated to strike the tubes; the scale was 1:30. The dimensions of the indenter head were much smaller than the tube diameter in order to concentrate the impact load. Global motions of the impacted tubes were modeled by springs introduced at the boundaries, and their stiffnesses were determined according to an equivalent single-degree-of-freedom (SDOF) model. Numerical simulations of the experiments were conducted using the nonlinear finite element (FE) software LS-DYNA. The experimental and numerical results were compared and discussed with respect to force-deformation curves, deformation modes and energy dissipation. Existing theoretical solutions for the lateral indentation resistance of tubes were also compared to the experimental and numerical simulation data. The results indicated needs for new solutions when the impact loads become concentrated.

Simulation and Experiment Study on Energy Absorption of a Thin-Walled Tube Component with Vertical Strip

In order to better solve anti-impact problem of hydraulic support, based on the previous study of anti-impact device by the author’s team, a thin-walled tube component with vertical strip which works as an energy absorbing component is designed and simulation model of the component is established, and energy absorption characteristics of the component is studied. Experimental verification is done and the simulation model is optimized based on the experimental data. Based on the above works, parameters of the component are re-optimized and energy absorption characteristics of the component are tested. Through supporting reaction force–deformation curve of the thin-walled tube component with vertical strip, it can be seen that deformation stability of the component is high, and the initial peak force difference ratio of energy absorbing components before and after structural optimization is reduced from 4.8% to 1.04%. The results show that energy absorption characteristics of the thin-walled tube component with vertical strip are further improved, and accuracy of the simulation model is also further improved.

Measurement of Contact Force–Deformation Curves of Colliding Two Identical Spheres

Measurement of Contact Force–Deformation Curves of Colliding Two Identical Spheres

Bending mechanics test and parameters calibration of ramie stalks

Research and development of ramie harvesting equipment is a key link to revitalize ramie industry, problems such as the tendency of stalks to tangle and clog the machine are very problematic, seriously affect the quality and fluency of the harvester. The structure of ramie stalk is complex, and the mechanical properties of each component vary greatly, collision between stalk and machine creates complex stress relationship. By building a finite element model, it is possible to analyze the stress state of the stalk during bending from a microscopic perspective, and to analyze the complex stress–strain situation within the stalk. The purpose of this paper is to establish a standard ramie stalk bending finite element model to provide a theoretical basis for the subsequent kinematics and dynamics. Firstly, material experiments were carried out on ramie straw. The structural and mechanical parameters of the straw components were obtained through measurement and calculation tests, and the force–deformation curves for straw bending were obtained. Bending finite element simulations were carried out on the basis of mechanical tests, and the parameters such as dynamic friction coefficient, wood Poisson's ratio and bast Poisson's ratio were determined by the central combination design. Then established an accurate bending finite element simulation model of ramie stalk, the accuracy of the model was verified at the end. In this paper, the key parameters of the ramie stalk model were calibrated through a combination of material tests and simulations. All parameters of the ramie stalk model were finally obtained, and the bending mechanical properties of the ramie stalk were analysed by applying finite element analysis. This bending mechanics simulation model can be used for kinematic and dynamics simulation analysis of conveying and baling to provide a theoretical basis for the structural design of the harvester. The methods explored here can be applied to other slender straw crops.

Solvent-free encapsulation of β-carotene in natural flaxseed oil bodies induced via tepidity-physical field treatment: Formation, characteristic and stability

As a natural plant-derived oil-in-water emulsion, oil bodies (OBs) with fine membrane structure have a great potential to be a typical green entrapping system. The dense membrane of OBs protects the interior readily oxidizable substance, but also severely blocks the passage of biologically active substances. Given full considerations of both the mobility and rigidity of the OBs membrane, in this work, tepidity-ultrasonic (TU) method was firstly applied to incorporate β-carotene within flaxseed oil bodies (FOB). Laser Scanning Confocal Microscopy (LSCM), Atomic force microscopy (AFM) and Cryo-Scanning Electron Microscope (Cryo-SEM) measurements demonstrated that TU could induce the transformation of FOB membrane and greatly promoted β-carotene encapsulation into FOB interior. In consistent with rheology, the infrared, ultraviolet and fluorescence spectra of the membrane protein, as well as force-deformation curves confirmed that the inserted β-carotene weaken the interaction of components in the membrane to a sharp reduction in membrane stiffness. The subsequent ultrasonic triggered interfacial membrane remodeling and particle size reduction, causing a significant improvement of interfacial membrane stiffness nearly back its original state and ultimately improving the stability of the system. The optimal encapsulation rate of β-carotene (96.88%) could be obtained at optimized ultrasonic condition. After 30-day storage, the relative encapsulation efficiency of β-carotene in FOB-β-TU remained at 84.06%. Thus, this paper reveals that the synergistic effect of tepidity-stirring and ultrasonic provides the possibility for solvent-free assisted encapsulation of hydrophobic bioactive substances in natural OBs. This easily applicable method is also conducive to fulfill its application in multiple food processing.

基于单轴压缩物理试验和虚拟仿真的钙果力学模型构建

The mechanical parameters of Cerasus humilis are the basic data for subsequent studies on fruit deformation, damage, and movement characteristics during harvesting and transportation, but these parameters are rarely reported. Relevant mechanical parameters of whole fruit compression are calculated by comparing physical tests and virtual simulations. The orthogonal rotating combined experimental design was used to arrange the simulation tests, with the elastic modulus (E), yield limit (Ey), and tangent modulus (Et) as the influence factors and compression force as the result. Response surface optimization was employed to find the closest test point to the force–deformation curve of the physical test. The parameters of the pulp test point are as follows: E = 0.923 MPa, Ey = 0.0897 MPa, and Et = 0.478 MPa. Results show that the step on the force–deformation curve was not the beginning of the pulp yield, which was substantially earlier than the strain rate at the simulation step. The region of increased stress in the pulp first appeared at the junction with the core due to stress concentration. Combining virtual and physical tests to solve the mechanical parameters of fruits is more suitable than testing the standard pulp sample.