Load Penetration Research Articles

Unique structures and material properties of the skin in different body regions of three species of fish.

Benefitting from its unique helically arranged fiber structures, fish skin is a superior biological protective tissue. Reported here is a study of the microscopic morphological characteristics and mechanical properties of the skin of three species of fish, that is, Taihu white fish (Erythroculter ilishaeformis), grouper (Cichlasoma managuense), and yellowfin seabream (Ditrema temminckii Bleeker), revealing the special protective mechanisms of fish skin. Experiments involving scanning electron microscopy show that the stratum compactum is the main part of fish skin and comprises helically stacked fibers, with the helical ply angles of the fibrous layers differing significantly for the different fish species and in different regions of their bodies. Tension and penetration experiments show that fish skin provides a fish's body with considerable mechanical protection from lacerations and bites inflicted by its natural enemies. Moreover, the mechanical tests show that fish skin has two different defensive mechanisms against tension and penetration loads, thereby offering a novel idea for designing body armor that is both flexible and tough.

Design and verification of flexible penetrometer for planetary subsurface exploration

In-situ extraction of geological information from planetary subsurfaces is of great importance. To achieve this goal with low power consumption and deep penetration, a novel subsurface sounding system for planetary regolith exploration is proposed based on the operating principle of tape measures. Penetration model analysis and validation were conducted. The penetration mechanics of the penetrator head and body were modeled separately, and static penetration tests were performed to verify the feasibility of the penetrator and modify the penetration load model. As the structural design of the penetrator was completed, a cam-based impact clamping scheme was proposed. The impact system dynamics model was established to analyze the effect of pene-tration resistance and kinetic parameters on the penetration capability of the penetrator. The principle prototype of the penetrator was developed, and a load-free simulated planetary regolith penetration test system was built to verify the correctness of the design. This study may provide technical support for the future application of flexible detectors in planetary exploration.

Economic Feasibility of a Renewable Integrated Hybrid Power Generation System for a Rural Village of Ladakh

This paper mainly dealt with the technical and economic feasibility of an off-grid hybrid power generation system for a remote rural Turtuk village of Ladakh, located in the northern part of India. The study showed that the proposed configured renewable integrated hybrid system, using Hybrid Optimization of Multiple Energy Resources (HOMER) software, efficiently met the energy demand, exhibiting optimum performance with low investment. The proposed PV(115 kW)/Wind(1 kW)/Battery(164 strings of 6 V each)/DG(50 kW) hybrid system was a highly commendable, feasible solution preferred from a total of 133,156 available solutions resulting from HOMER simulations. The net present cost and energy cost of the proposed configuration were $278,176 and $0.29/kWh, respectively. The proposed hybrid configuration fulfilled local load, with 95.97% reduced dominant harmful carbon dioxide emission, as compared to the sole us of a diesel generator power supply system. The technical performance of the hybrid system was ensured, with advantages including the highest renewable penetration and least unmet load. Furthermore, the analysis exclusively evaluated the impact of the system’s economic parameters (namely, its expected inflation rate, nominal discount rate, and project lifetime) on the net present cost and cost of energy of the system using a noble single fix duo vary approach.

Under voltage load shedding and penetration of renewable energy sources in distribution systems: a review

ABSTRACT The growing energy demand and the emerging environmental concerns across the globe caused increasing penetration of renewable energy sources (RESs) in distribution systems. One of the major issues faced by modern distribution systems with high RESs penetration is voltage instability. Generally, voltage instability can lead to voltage collapse, which is one of the key drivers for blackout incidents around the world. Under voltage load shedding (UVLS) schemes are usually executed as the final option to prevent a large-scale blackout or voltage collapse. But ever-increasing integration of RESs in distribution systems creates an additional threat to the existing UVLS schemes. Therefore, new UVLS methods are necessary to provide the appropriate corrective scheme for distribution systems, particularly when connected with RESs. This paper reviews and updates the recent UVLS methods emphasizing on distribution network application. In addition, the contributions and limitations of the conventional, adaptive, and computational intelligence techniques of UVLS are highlighted. Moreover, this paper provides an overview of the voltage stability indices applied for UVLS methods. Also, at the end of this review article, the further research directions to improve the safety of modern distribution systems during emergencies using UVLS are drawn as the conclusion.

Dimensionless Analysis to Determine Elastoplastic Properties of Thin Films by Indentation

By assuming the elastoplastic properties of thin-film materials, a reverse analysis method is proposed by deriving a dimensionless function for the indentation process. The substrate effect is taken into account by assuming a perfect interface between thin-film and substrate materials. In order to obtain the applied load–penetration depth (P-h) curves, the indentation process is numerically modeled as an axisymmetric problem with a rigid-body Berkovich indenter on the semi-infinite substrate when performing finite element (FE) simulations. As a typical soft film/hard substrate problem, the elastic substrate is assumed and the power–law model is used to describe the constitutive properties of thin-film materials. Varying elastic modulus (10–50 GPa), yield strength (60–300 MPa), and hardening exponent (0.1–0.5) characterize different elastoplastic mechanical properties of thin-film materials with film thickness of 10–30 μm. Owing to the good trending P-h curves with the maximum indentation depth up to the 2/3 film thickness for different elastoplastic thin-film materials, a dimensionless function is derived and validated based on the predictions by reliable FE simulations. The proposed dimensionless function elegantly elucidates the essential relationship between the elastoplastic mechanical properties of the thin-film material and indentation responses (e.g., loading and unloading variables). The elastoplastic constitutive curves predicted by the proposed reverse method are confirmed to be in good agreement with the stress-strain curves of materials by FE simulations with the randomly selected elastoplastic mechanical properties and film thicknesses. This study provides a theoretical guidance to understand the explicit relationship between elastoplastic mechanical properties of the thin-film material and indentation responses.

Robust control of adaptive power quality compensator in Multi-Microgrids for power quality enhancement using puzzle optimization algorithm

The primary purpose of this paper is to design a novel multi-microgrid connection that uses power compensation methods to improve voltage profiles and reduce harmonic distortions using specific compensation devices in low inertia systems. The utilized compensation device is an adaptive power quality compensator (APQC) which includes series and shunt compensators. Thyristor controlled series capacitor (TCSC) is used as a series compensator to alleviate the dynamic voltage profile as well as diminish transient voltage. A shunt active power filter (SAPF) is utilized as a shunt compensator to improve the power factor and lessen voltage and current harmonics. The TCSC has a power level of error of the PID controller, while the SAPF has a dynamic multi-level of errors of the PID controller. Further, the recent swarm intelligence-based puzzle optimization algorithm is employed to get the best self-tuning of the PID controller gains to reveal the act of the APQC typology. The efficacy of the presented APQC with the multi-level mechanism approach, assessed using Matlab/Simulink time-domain simulations, has been compared with the recently reported literature. Two operation modes are addressed, one for the island mode and the other for the grid-connected mode with significant renewable generation penetration and nonlinear loads. APQC successfully enhances the power quality of multi-microgrids (MMGs), according to theoretical research and simulation statistics. Finally, three comparative study assessments of numerous optimization approaches, with a unified power flow conditioner (UPFC), and with other series-shunt compensators like distributed power condition controller (DPCC) are proposed to attain efficacy and strength of the compensator.

Effect of Hybrid Weave Patterns on the Mechanical Performance of Woven Fabrics

ABSTRACT Improvement in mechanical properties of the natural fiber reinforcement for potential use in the composite for mechanical performance is a key focus of researchers in recent years. However, few studies are available in the literature on the mechanical performance of hybrid-woven fabrics. In this article, the effect of the weave structure of reinforcing fabric on mechanical performance has been investigated. Jute-based woven fabrics having four different weave structures (matt, sateen, and hybrid-weave A/B) were developed in the in-house lab using a shuttle dobby weaving machine. The tensile test and puncture tests were performed to evaluate the mechanical performance by varying the weave architecture. The sateen weave exhibited maximum penetration load during a puncture test. The results demonstrated a significant improvement in the tensile strength by using a hybrid weave in the warp direction. However, sateen woven fabric demonstrated enhancement in the tensile attributes in the weft-wise direction. Similarly, a hybrid weave consisting of a combination of sateen and matt weave exhibited a maximum stiffness value. To check the statistical significance of the results, ANOVA analysis was performed. The findings of ANOVA suggest that the results are statistically significant. This research will open a new avenue in the field of reinforcement composite material.

Risk-aware energy management of a microgrid integrated with battery charging and swapping stations in the presence of renewable resources high penetration, crypto-currency miners and responsive loads

The penetration of renewable resources and electric vehicles has increased in recent years due to various benefits such as reducing environmental pollution. This paper optimizes the energy management of a microgrid integrated with battery charging and swapping stations in the presence of renewable resources and crypto-currency miners as an emerging critical load with high energy consumption. In such structures, the fluctuation of renewable energies decreases reliability and increases energy market trading. Hence, the conditional value-at-risk index is utilized to analyze the risk of uncertainties. Furthermore, the influence of responsive local loads and incoming vehicles into the stations is investigated using demand response programs. In order to implement the presented programming, a real distribution network in Kermanshah, Iran, is selected as the case study. The results show that the risk-averse strategy with α = 0.85 and β = 0.8, reduces the expected revenue by about 636.355 $ compared to the risk-neutral strategy. In addition, the swapping station can be used as a bulk storage, where it stores about 43.56 MWh in low-price times and injects about 20.04 MWh in high-price times to support the local system. The demand side management also increases the revenue even under the worst-case conditions by about 79.623 $.

Determine the unique constitutive properties of elastoplastic materials from their plastic zone evolution under nanoindentation

The evolution of the plastic zone underneath the indenter is challenging to be described during nanoindentation, which is recently known to be crucial to establish a constitutive model that features the plastic properties of the substrate materials based on their indentation responses. Using molecular dynamics and axisymmetric finite element (FE) simulations in this study, we show that the plastic zone shape in the elastoplastic materials is hemispherical in a broad range of length scales under a three-sided pyramid-shaped Berkovich indenter. By considering the critical factors of the applied load–penetration depth (P–h) curve, dimensional analysis is performed to derive dimensionless functions regarding the radius of the hemispherical plastic zone. For the loading and unloading stages in extensive FE simulations, a set of polynomial functions are proposed by associating the instantaneous and residual plastic zone radii with constitutive parameters. In addition to Young's modulus and the hardening exponent, the ratio of the representative stress to the reduced modulus is found to be crucial for predicting the plastic deformation. Lastly, the proposed dimensionless function reveals that the plastic zone radii are drastically different for three representative materials with identical P–h curves as confirmed by three independent methods. This result suggests that the proposed plastic zone radius in the dimensionless analysis helps to overcome the challenging uniqueness issue for decades to determine the unique elastoplastic properties of materials based on nanoindentation responses.

Unambiguous Identification of Crystal Plasticity Parameters from Spherical Indentation

Identification of elastic and plastic properties of materials from indentation tests received considerable attention in the open literature. However, unambiguous and automatic determination of parameters in the case of the crystal plasticity (CP) model is still an unsolved problem. In this paper, we investigate the possibility to unambiguously identify the CP parameters from spherical indentation tests using finite element method simulations combined with evolutionary algorithm (EA). To this aim, we check the efficiency and accuracy of EA while fitting either load–penetration curves, surface topographies, or both at the same time. By fitting the results against simulation data with known parameters, we can verify the accuracy of each parameter independently. We conclude that the best option is to fit both load–penetration curve and surface topography at the same time. To understand why a given fitting scheme leads to correct values for some parameters and incorrect values for others, a sensitivity analysis was performed.

The mechanism of stab resistance of carbon fiber reinforced polymer

In this paper, the puncture resistance of carbon fiber reinforced polymer (CFRP) with different thicknesses under various puncture energy was studied by in-situ observation. The puncture failure process of CFRP was analyzed using a high-speed camera and thin-film pressure sensor in terms of damage image and local pressure change. The experimental results show that the puncture threshold load (PTL) representing material penetration is usually located at the initial loss position of material stiffness. The penetration load can be divided into linear growth and delamination failure zones. Image localization was used to mark the puncture feature points on the puncture force–displacement curve to help characterize the puncture failure process. The theoretical equations of puncture force and displacement before material penetration are proposed and verified by introducing yield stress and friction force, and the correlation between the material thickness and the puncture resistance was proved. In addition, the failure modes and fracture morphology of CFRP after puncture are analyzed and summarized. After puncture impact, fiber fracture, pull out and slip deformation under the action of tensile force and cutting force, and matrix fracture and peel damage. The increase of impact energy leads to a broader range of impact damage but does not change the failure modes.

Effect of key design parameters on high temperature performance of asphalt mixtures

• Four key design parameters were selected to study their effect on the high temperature performance of asphalt mixtures. • The uniaxial penetration shear test was applied to analyze the variation of high temperature performance of asphalt mixtures. • The multi-way (one way and two-way) ANOVA was adopted to understand the role of factors on the high temperature performance of asphalt mixtures. Rutting is one of the main distresses for asphalt pavements and it has adverse effect on service life. It is associated with the high temperature performance of asphalt mixtures. The paper attempts to investigate the effect of key design parameters on high temperature performance of asphalt mixtures. Initially, the factors consisting of air void ratio, compaction effort, maximum nominal particle size and asphalt binder grade were selected and then the uniaxial penetration shear test was applied to analyze the variation of high temperature performance of asphalt mixtures. Accordingly, the maximum penetration load and the shear strength were used as evaluating indicators. Eventually, the multi-way (one way and two-way) ANOVA was adopted to understand the role of factors on the high temperature performance. The results indicate that the high temperature performance increases an average of 30 % when compaction effort and maximum nominal particle size rise. In contrast, the raise of asphalt grade and air void ratio decrease of 10 %∼30 % of high temperature performance. At the same time, the increase of compaction effort improves the high temperature performance about 20 %∼50 % at two variables condition. In one-way ANOVA, there is no statistically significant difference in the maximum penetration load when changing the air void ratio levels. The compaction effort, maximum nominal particle size, asphalt binder grade significantly influence the change of maximum penetration load. In terms of two-way ANOVA, any combined two factors significantly affect the high temperature results. This provides some guidance for design of asphalt mixtures to elevate high temperature performance.

White Shark Optimizer for Multi-Objective Optimal Allocation of Photovoltaic Distribution Generation in Electrical Distribution Networks Considering Different Kinds of Load Models and Penetration Levels

White Shark Optimizer for Multi-Objective Optimal Allocation of Photovoltaic Distribution Generation in Electrical Distribution Networks Considering Different Kinds of Load Models and Penetration Levels

Honey Badger Algorithm Based Network Reconfiguration and Integration of Renewable Distributed Generation for Electric Vehicles Load Penetration

Honey Badger Algorithm Based Network Reconfiguration and Integration of Renewable Distributed Generation for Electric Vehicles Load Penetration

Numerical analysis on impact response of ice sheet against impactor penetration loading

ABSTRACT Damage features of the ice sheet have been achieving increasing attention due to its important engineering applications, but there still lacks related research concerning the ice damage characteristics under impacting load. In this paper, the JH-2 constitutive model is applied to describe the ice material properties. The numerical simulations of ice material suffering failure mode were conducted to validate the effectiveness of ice material. With the validated ice material model, studies are conducted to investigate the general damage features of ice sheets subjected to impacting load. The influence factors including head shapes of the impactor, water support and non-dimensional mass and length to ratios of impactor on ice damage are investigated. Moreover, the penetration load and combination of underwater explosion load acting on the ice sheet are discussed. The results show that the head shape of the impactor has a significant influence on ice damage characteristics during the whole ice-breaking process.

Soil profile analysis based on the identification of the bevametric parameters using cone penetrometer

The navigation in a deformable soil is related to the determination of traction and motion resistance via the soil strength. This strength is a function of parameters that are usually estimated using the bevameter tool. However, this tool is not usually available, hence the usage of another tool called cone penetrometer. In this study a new relationship was developed to estimate the bevameter parameters. This relation combines all bevameter parameters; (shear strength parameters and load penetration parameters), with a measurement called cone index. This equation is compared to another equation existing in the literature, that use only the load penetration parameters as a function of cone index, and then validated using experimental data obtained from Waterways Experiment Station (WES). The result shows that our equation is optimal compared to others existing in the literature. Finally, this equation is used to find all bevametric parameters of the soil inside the greenhouse strawberries.

Probabilistic site characterisation using monitored spudcan installation data

Predicting spudcan penetration is essential for reducing risk during the installation of an offshore mobile jack-up platform. However, predictions made prior to installation often deviate from those recorded in practice, mainly because inherent uncertainties in seabed soils are not adequately considered. In this paper, the characteristics of the seabed are quantified using monitored spudcan installation data by developing a Bayesian framework coupled with Metropolis algorithm-based Markov chain Monte Carlo (MCMC) simulation. Applied to sand overlying clay conditions multiple readings from the load–penetration curve are used to derive statistical interpretations of seabed parameters such as sand thickness, sand friction angle and the undrained shear strength profile of clay. Illustrative examples demonstrate the proposed method using data from geotechnical centrifuge tests and a monitored offshore jack-up. The accuracy of the method is also retrospectively examined against a database of 66 centrifuge tests. The results show that the proposed method can provide consistent soil parameters with reduced uncertainty regardless of the influence of the updating sequence, number of MCMC chains, scale factors and the prior distributions applied. This method offers the offshore industry a new methodology to statistically interpret seabed conditions by incorporating monitored data. Potentially it could be combined with spatial interpolation methods to infer ground conditions and more accurately predict future spudcan installations.

Optimal Planning of Electric Vehicle Charging Station along with Multiple Distributed Generator Units

Saving energy through the minimization of power losses in a distribution system is a key activity for efficient operation. Distributed Generation (DG) is one of the most efficient approaches to minimize losses. With increase in installation of Electric Vehicle Charging Stations (EVCSs) for Electrical Vehicles (EVs) in larger scale, optimal planning of EVCSs becomes a major challenge for distribution system operator. With increased EV load penetration in the electricity system, generation-demand mismatch and power losses increases. This results in poor voltage level, and deterioration in voltage stability margin. To mitigate the adverse impacts of increasing EV load penetration on Radial Distribution Systems (RDS), it is essential to integrate EVCSs at appropriate locations. The EVs integration into smart distribution systems involves Grid-to-Vehicle (G2V) and Vehicle-to-Grid (V2G) in charging and discharging modes of operation respectively for exchange of power with the grid thus resulting in energy management. The inappropriate planning of EVCSs causes a negative impact on the distribution system such as voltage deviation and an increase in power losses. In order to minimize this, DG units are integrated with EVCSs. The DGs assist in keeping the voltage profile within limitations, resulting in reduced power flows and losses, thereby enhancing power quality and reliability. Therefore, the DGs should be optimally allocated and sized along with the EVCS to avoid problems such as protection, voltage rise, and reverse power flow problems. This paper showcases a method to minimize losses using optimal location and sizing of multiple DGs and EVCS operating in G2V and V2G modes. The sizing and location of different types of DG units including renewables and non-renewables along with EV charging station is proposed in this study. This methodology overall reduces the power losses and also improves voltages of the network. The implementation is done by using the Simultaneous Particle Swarm Optimization technique (PSO) for IEEE 15, 33, 69 and 85 bus systems. The results indicate that the proposed optimization technique improves efficiency and performance of the system by optimal planning and operation of both DGs and EVs.

Mixed-Integer Linear Programming for Decentralized Multi-Carrier Optimal Energy Management of a Micro-Grid

Increasing the load demand and penetration of renewable energy sources (RESs) poses real challenges for optimal energy management of distribution networks. Moreover, considering multi-carrier energy systems has increased the efficiency of systems, and provides an opportunity for using the advantages of RESs. In this regard, we adopted a new framework based on the new challenges in the multi-carrier energy micro-grid (MEMG). In the proposed method, a comprehensive MEMG was modeled that benefits from a large assortment of distributed energy resources (DERs), such as micro-turbines, fuel cells, wind turbines, and energy storage. Considering many DERs is necessary, because these resources could cover one another’s disadvantages, which have a great impact on the total cost of the MEMG and decrease the emission impacts of fossil-fuel-based units. Furthermore, waste power plants, inverters, rectifiers, and emission constraints are considered in the proposed method for modeling a practical MEMG. Additionally, for modeling the uncertainty of stochastic parameters, a model based on a multilayer neural network was used in this paper. The results of this study indicate that using a decentralized model, along with stochastic methods for predicting uncertainty, can reduce operational costs in micro-grids and computational complexity compared with optimal centralized programming methods. Finally, the equations and results obtained from the proposed method were evaluated by experiments.

An Eagle Strategy Arithmetic Optimization Algorithm for Frequency Stability Enhancement Considering High Renewable Power Penetration and Time-Varying Load

This study proposes a new optimization technique, known as the eagle strategy arithmetic optimization algorithm (ESAOA), to address the limitations of the original algorithm called arithmetic optimization algorithm (AOA). ESAOA is suggested to enhance the implementation of the original AOA. It includes an eagle strategy to avoid premature convergence and increase the populations’ efficacy to reach the optimum solution. The improved algorithm is utilized to fine-tune the parameters of the fractional-order proportional-integral-derivative (FOPID) and the PID controllers for supporting the frequency stability of a hybrid two-area multi-sources power system. Here, each area composites a combination of conventional power plants (i.e., thermal-hydro-gas) and renewable energy sources (i.e., wind farm and solar farm). Furthermore, the superiority of the proposed algorithm has been validated based on 23 benchmark functions. Then, the superiority of the proposed FOPID-based ESAOA algorithm is verified through a comparison of its performance with other controller performances (i.e., PID-based AOA, PID-based ESAOA, and PID-based teaching learning-based optimization TLBO) under different operating conditions. Furthermore, the system nonlinearities, system uncertainties, high renewable power penetration, and control time delay has been considered to ensure the effectiveness of the proposed FOPID based on the ES-AOA algorithm. All simulation results elucidate that the domination in favor of the proposed FOPID-based ES-AOA algorithm in enhancing the frequency stability effectually will guarantee a reliable performance.