Types Of Mechanical Damage Research Articles

Interference of mechanical damage on the physiological performance of corn seeds

Corn (Zea mays L.) is cultivated and consumed globally due to its nutritional qualities and short production cycle. However, during harvesting, processing, transportation, and storage, seeds are susceptible to various types of damage that can compromise their productive capacity, affecting both germination and plant vigor. Therefore, this study aimed to evaluate the physiological quality of corn seeds subjected to different types of mechanical damage. The experiment was conducted at the Laboratory of Storage and Processing of Agricultural Products at the Federal University of Campina Grande, Campina Grande, Paraíba, Brazil. Corn seeds were subjected to four types of mechanical damage: hammering, cutting, abrasion, and perforation, alongside a control sample that did not undergo any mechanical damage. Each treatment (mechanical damage) consisted of 200 seeds, which were evaluated through germination tests, including first count, germination rate, germination speed index (GSI), seedling dry weight, and root length. The experiment was conducted in Completely Randomized Design. Data were subjected to Analysis of Variance, and means were compared using the Scott-Knott test (P ≤ 0.05) when necessary. Mechanical damage reduces the germination and vigor of corn seeds. Cutting-type damage affects corn seeds more severely, reducing germination by an average of 80% and impairing vigor.

Fracturas Supracondíleas Humerales Pediátricas. Comparación de dos Técnicas de Reducción

Objective: To analyze the results of the surgical technique placement of Kirschner pins lateral versus crossed in the management of supracondylar fractures of the humerus in pediatric patients. Methodology: All pediatric patients with humeral supracondylar fracture who required surgical intervention and were subsequently evaluated 24 hours and 6 months after surgical treatment to observe and compare the differences between each patient. surgical technique used. Taking into account the acute and late complications that occurred, through an analysis with the Mann-Whitney test. Results: For the present studies, 44 pediatric patients were evaluated, of whom 70% were men and 30% women, in whom nerve and angular complications presented without any significant importance with the sex and age of the patients, with ulnar nerve involvement being the most frequent with 33% in cross placement. When carrying out the comparison with discrimination of variables, it is obtained that the placement laterally presents fewer early and late post-surgical complications and that such are not due to chance. Or the present study, it is considered that a placement of Kirschner pins laterally regardless of the member, age, gender or classification; leads to better post-surgical results. Limitations or implications: In the present study, the type of mechanical damage that causes this type of fracture was not included, nor was the Baumann angle considered. Another limitation inherent in the pediatric population is the ability of the examiner to detect a neurological deficit, especially in young patients since reports of a physical examination are always subjective. Furthermore, given the limited details of the specific damage mechanism, the number of damages caused by high-energy mechanisms may be underestimated. Originality or value: Its importance lies in the fact that both surgical techniques were performed by the same surgeons and that it is a study in the mexican population, being a contribution to the literature of this country. Findings or conclusions: Both surgical techniques present post-surgical results with cases of nerve injury, angular deformity, pain and persistent edema, but the one that presents them less frequently in the technique of placement of Kirschner pins laterally, in addition to causing statistical significance in terms of the decrease of presenting cubitus valgus in the late follow-up of the patients.

Combining Chitosan, Stearic Acid, and (Cu-, Zn-) MOFs to Prepare Robust Superhydrophobic Coatings with Biomedical Multifunctionalities.

There is an urgent need to develop a series of multifunctional materials with good biocompatibility, high mechanical strength, hemostatic properties, antiadhesion, and anti-infection for applications in wound care. However, successfully developing multifunctional materials is challenging. In this study, two superhydrophobic composite coatings with good biocompatibility, high mechanical strength, strong antifouling and blood repellency, fast hemostasis, and good antibacterial activity areprepared on cotton fabric surface by simple, green, and low-cost one-step dip-coating technology. The results discussed in the manuscript reveals that the two superhydrophobic composite coatings can maintain good mechanical stability, strong water repellency, and durability under various types of mechanical damage, high-temperature treatment, and long-term strong light irradiation. The coatings also exhibit good repellency to various solid pollutants, highly viscous liquid pollutants, and blood. In vitro and in vivo hemostatic experiments show that both composite coatings havegood hemostatic and anticlot adhesion properties. More importantly, this superhydrophobic coating prevents bacterial adhesion and growth and released Cu2+ and Zn2+ ions and chitosan to achieve bactericidal properties, thereby protecting injured skin from bacterial infection. The two superhydrophobic coatings enhance the antifouling, antiadhesion, hemostatic, and antibacterial functions of blood-repellent dressings and therefore have broad application prospects in medical and textile fields.

Mechanical Branch Wounding Alters the BVOC Emission Patterns of Ficus Plants

Tree leaves emit biogenic volatile organic compounds (BVOCs) in response to mechanical wounding by insect folivores. However, BVOCs are also released from leaves in response to damage to other tree organs. In this study, we hypothesized that if trees utilize BVOCs to defend against leaf herbivory, BVOCs emitted in response to leaf wounding would be different from those emitted in response to other types of mechanical damage. To test this hypothesis, we measured BVOCs emitted from the leaves of four Ficus species in response to leaf-cutting, branch-cutting, leaf-branch-cutting, and control (constitutive BVOCs). We found that leaf-cutting triggered the emission of BVOCs, but their emission patterns were species-specific, and the overall BVOC composition did not significantly differ from that of constitutive BVOCs. In contrast, branch-cutting triggered the emission of many BVOCs, some known as parasitoid attractants and herbivore deterrents. Our study suggests that plant defense mediated by BVOCs is highly species-specific and not effective for attracting herbivore enemies when unrelated disturbances such as tree falls and windstorms occur. Additionally, we recommend avoiding ex situ BVOC sampling of cut plants, as this method alters BVOC emission patterns from both intact and damaged leaves.

Deep Learning Empowered Structural Health Monitoring and Damage Diagnostics for Structures with Weldment via Decoding Ultrasonic Guided Wave.

Welding is widely used in the connection of metallic structures, including welded joints in oil/gas metallic pipelines and other structures. The welding process is vulnerable to the inclusion of different types of welding defects, such as lack of penetration and undercut. These defects often initialize early-age cracking and induced corrosion. Moreover, welding-induced defects often accompany other types of mechanical damage, thereby leading to more challenges in damage detection. As such, identification of weldment defects and interaction with other mechanical damages at their early stage is crucial to ensure structural integrity and avoid potential premature failure. The current strategies of damage identification are achieved using ultrasonic guided wave approaches that rely on a change in physical parameters of propagating waves to discriminate as to whether there exist damaged states or not. However, the inherently complex nature of weldment, the complication of damages interactions, and large-scale/long span structural components integrated with structure uncertainties pose great challenges in data interpretation and making an informed decision. Artificial intelligence and machine learning have recently become emerging methods for data fusion, with great potential for structural signal processing through decoding ultrasonic guided waves. Therefore, this study aimed to employ the deep learning method, convolutional neural network (CNN), for better characterization of damage features in terms of welding defect type, severity, locations, and interaction with other damage types. The architecture of the CNN was set up to provide an effective classifier for data representation and data fusion. A total of 16 damage states were designed for training and calibrating the accuracy of the proposed method. The results revealed that the deep learning method enables effectively and automatically extracting features of ultrasonic guided waves and yielding high precise prediction for damage detection of structures with welding defects in complex situations. In addition, the effectiveness and robustness of the proposed methods for structure uncertainties using different embedding materials, and data under noise interference, was also validated and findings demonstrated that the proposed deep learning methods still exhibited a high accuracy at high noise levels.

Effects of VA Rating on the Fault Diagnosis of Power Transformer Using SFRA Test

The electric power transformer is an essential part of an electrical power system since it is used to step up or down voltage levels to maintain the system performance as well as possible. Frequency response analysis (FRA) is one of the most widely used techniques for detecting various types of mechanical damage in transformers. The equivalent circuit of the transformer will be represented by a complex network of R, L, and C elements in the FRA technique. For transformer faults diagnosis, various calculation techniques and diagnostic techniques may be used, such as acoustic emission analysis, thermal images of electromagnetic radiation, transformer temperature, and humidity analysis. SFRA test is one of these techniques that could be used to determine the fault type based on its response over a wide frequency range. The main challenge of the SFRA test is that the functional interpretation requirement for this test is not universally accepted Also statistical features are defined for this SFRA response to be used in fault detection and classification. In this paper, the effect of the transformer rating on the fault diagnosis techniques using SFRA is tested. Also, the effect of the transformer VA rating on the statistical parameters and the classification rules of fault diagnosis is discussed. Finally, the features used in fault diagnosis are ranked according to its independence of the transformer rating resulting in a more accurate matching fault diagnosis technique.

Bruise Damage Susceptibility and Fruit Quality Assessment of Pear

Introduction: Bruising is a type of mechanical damage that challenges fresh horticulture production efforts, which occurs mainly due to excessive compression and impact forces during postharvest operations resulting in quality deterioration of fresh produce and reduction in economic value. Objective: This study aims to assess the bruise susceptibility of imported pears and determine its effect on pear quality attributes. Materials and Methods: Each Pyrus communis, variety ‘D'Anjou’ imported pears was impacted by a known mass steel ball at three different drop heights (20, 40, and 60 cm). Bruised fruit was stored at 22°C with 45±5% RH and 10°C with 85±5% RH for 48 hours storage period. Pears were also subjected to different quality analyses like color, firmness, weight loss, and total soluble solids (TSS). The analysis was conducted by performing two factorial balanced analyses of variance (ANOVA). Results: Bruise area, bruise volume, and bruise susceptibility were the highest at higher drop impact (60 cm) on pears stored at 22°C and the lowest were at lower drop impact (20 cm) on pears stored at 10°C. Furthermore, there was a statistically significant impact of drop height and temperature on bruising susceptibility. Besides, statistics showed a significant impact of the studied factors (temperature and drop height) on quality parameters of pears such as lightness (L*), redness-greenness (a*), weight loss, and firmness after 48 hours of storage Conclusion: Mechanical damages like bruising can be affected by many factors like storage temperature and impact level force. Finally, it was concluded that mechanical damages like bruising can be affected by many factors like storage temperature and impact force. Overall, this study can consider as a guideline for workers during postharvest operations and handling.

Study Explores Mechanisms of Surface Damage on Coiled Tubing

This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper SPE 194254, “Study on Mechanism of Coiled Tubing Surface Damage in Injector Heads,” by Zhihong Zhou, Guofeng Zhang, Fayong Yuan, Tang Wang, Yunwei Gao, and Weijia Wang, Jianghan Shale Gas Development Technical Service Company, prepared for the 2019 SPE/ICoTA Well Intervention Conference and Exhibition, The Woodlands, Texas, USA, 26–27 March. The paper has not been peer reviewed. Although several kinds of mechanical damage cause coiled tubing (CT) failure, longitudinal plowing marks (LPMs) account for a large portion of such damage. Understanding the mechanisms of LPM damage on CT surfaces will help reduce the occurrence of this type of damage. In this paper, the authors study the stress status of CT string held by gripper blocks, the axial force distribution of gripper blocks, and the longitudinal resonance of CT strings in vertical wells. Introduction The overwhelming majority (greater than 80%) of CT failures have been classified into four categories: corrosion, mechanical damage, string-manufacturing issues, and human error. Of these, failures caused by mechanical damage constitute almost 30% of all CT failures. Further study of these types of mechanical damage reached the following two important conclusions: LPMs, which are injector-related, account for 46% of mechanical damage observed on CT strings from 2006 to 2017. Recent periods that have seen dramatic increases in mechanical damage coincide with plug milling and higher-grade-CT operations. The authors propose that the pressure in the CT string plays a role in mechanical damage. Contact Status Between CT and Gripper Blocks The gripper blocks carried by chains are used to hold CT strings in place. The gripper blocks are divided into single-pitch and two-pitch categories. The engagements between the CT string and the gripper blocks are sometimes suboptimal. The contact area between the gripper and CT string is only at the end-point of the arc, and the contact stress is much higher there than at the point at which the gripper blocks grip the original CT string. According to the von Mises yield criterion, if the von Mises stress is larger than the yield stress at any point, the material at that point will yield and plastic strain will be produced. Distribution of Gripper-Block Lifting Forces in the Injector Commonly, several pairs of gripper blocks engage the CT string to provide the friction forces needed for deployment and retrieval of the tubing into and out of the wellbore. How the axial loads of these pairs of gripper blocks are distributed is essential to safe operation and avoidance of CT damage. To obtain the axial load distribution of all pairs of gripper blocks, a mechanical model is created by the authors and discussed in the complete paper.

Analysis of roof membranes damaged by mechanical and climatic loads – pilot research

Realization of roof construction has many hidden risks, especially in buildings with diverse architecture. There is a problem about cooperation of individual works (vertical and horizontal constructions) on roof in this type of architecture, during the process of realization. Purpose of this research is to reveal risks in form of the group of major source of defects by mechanical damages. The most often types of mechanical damages were chosen in this research, which then were applied on individual types of roof membranes. Response of this damage was found out during the test procedure of water pressure by special laboratory machines. Furthermore, samples of roof membranes were subjected to the Impact test, which was actually focused on damage by hailstone impact from the atmosphere. The final outcomes of the measurements show that the material composition of each roof membrane can influence their whole waterproofing after application of certain type of mechanical damage. In the Impact test, samples were suffered from impact of the hails. This test signified that the choice of base material of thermal insulation below the roof membrane plays an important role.

Erratum to: Leaf area lost, rather than herbivore type, determines the induction of extrafloral nectar secretion in a tropical plant (Clerodendrum philippinum)

Plants produce extrafloral nectar (EFN) as indirect defense against herbivores. How different types of herbivores and types of damage affect EFN secretion rates are still not fully understood. In this study, a common shrub, Clerodendrum philippinum, was exposed to three different herbivores (with the two smaller species exposed at two densities), as well as three different types of mechanical damage. Feeding by a large generalist herbivore, the locust Atractomorpha sinensis, resulted in a significantly higher EFN secretion rate than the control treatment, while the other two herbivores, the specialist beetle Hoplasoma unicolor and generalist weevil Hypomeces squamosus, only caused significant increases in EFN secretion rate when present in high densities. Under these higher-density conditions, leaf area lost also increased. With respect to mechanical damage, a significant increase in EFN secretion rate, compared to control treatments, occurred only in the treatment with leaves damaged by scratching, but not in the treatments in which leaves had a hole punched in them or were cut from the stem. The significant regression of the change in EFN secretion rate on the amount of leaf area lost also indicates that leaf area lost to chewing insects may be an important factor in EFN secretion rate change. This research suggests that the induced response of EFN secretion in C. philippinum is a matter of the amount of the leaf area lost, more than a response to whether an insect is a generalist or specialist.

An Assessment and Estimation of the Damage Progression Behavior of IN738LC under Various Applied Stress Conditions Based on EBSD Analysis

In order to characterize the damage progression behavior of IN738LC and the influence of applied stress, the average misorientation within grains was evaluated using the electron backscattered diffraction (EBSD) method, by measuring over a million data points located across almost the whole zone of the tested specimens. It has been shown under various test conditions such as differing temperatures and strain rates that the average misorientation increases linearly with the increase of creep strains. As a result, it is confirmed that it is possible to assess the remaining creep fracture life from its average misorientation value regardless of the testing temperature and strain rate. In addition, the deformation and fracture mechanisms of various types of mechanical damage, such as tensile, impact, and creep conditions, were discussed by evaluating the characteristics of misorientation distribution. As a result, it has been revealed that creep damage affects a large area of the material, but it is localized near grain boundaries, which is completely different from that of tensile or impact damage. In conclusion, detailed investigation into the cross section of fracture samples using the EBSD misorientation analysis allows for the qualitative estimation of the fracture mode under various applied stress conditions, the cause of the fracture.

Mechanical properties and damage analysis of jute/polypropylene hybrid nonwoven geotextiles

Hybrid needlepunched nonwoven geotextiles are prepared in defined weight proportions of jute and polypropylene fibres. Subsequently, a comparison is made between various physical and mechanical properties of hybrid needlepunched nonwoven geotextiles. It was found that 40 wt.% jute was an optimum level in hybrid nonwoven geotextiles that had a comparable tensile strength and higher secant modulus specifically in the cross-machine (preferential) direction in comparison to 100% polypropylene based nonwoven geotextiles. Two types of mechanical damage (i.e., a horizontal cut and a circular hole) were artificially induced in the hybrid nonwoven geotextiles and their notch-sensitive behaviour and the failure mechanisms are reported.

Damage analysis and notch sensitivity of hybrid needlepunched nonwoven materials

Needlepunched nonwovens are complex three-dimensional (3D) entangled fibrous materials which are extensively used for a range of technical and industrial applications. The micromechanisms of deformation and fracture behavior of these materials are complicated and least understood. In this study, the tensile behavior of virgin and notched samples is investigated for hybrid needlepunched nonwoven materials consisting of polypropylene and viscose fibers in defined proportions. The notches in nonwovens were induced by two types of mechanical damage (circular hole and vertical cut) in three spatial positions of hybrid nonwovens tested in the machine, 45°, and cross-machine directions. The notch sensitivity of hybrid nonwovens was demonstrated by localized fiber failures occurring around the region of induced damages. It was established that the shape and spatial position of induced damage have significant influence on the tensile behavior of hybrid nonwoven materials. Higher viscose contents (60–80 wt%) in notched hybrid nonwovens yielded minimal tensile strength reduction specifically in the preferential (cross-machine) direction.

A Multi-resolution Experimental Methodology for Fatigue Mechanism Verification of Physics-based Prognostics


 
 
 An experimental methodology is proposed in this paper for mechanism verification of physics-based prognosis of mechanical damage, such as fatigue. The proposed experimental methodology includes multi-resolution in-situ mechanical testing, advanced imaging analysis, and mechanism analysis based on digital measurements. A case study is presented for fatigue crack growth mechanism investigation. In-situ fatigue testing at lower resolutions, i.e., optical microscopy, and digital image correlation is used to analyze the plastic deformation behavior and strain distribution near crack tips. In-situ fatigue testing under higher resolutions, i.e., scanning electron microscopy, and automatic image tracking is used to obtain detailed crack tip deformation and crack growth kinetics at the nanometer scales. Following this, the proposed experimental methodology is applied to two different metallic materials, aluminum alloys and steels. Very different experimental observations are observed and the underlying mechanisms are discussed in detail. The impact on the prognosis algorithm development is also discussed. Finally, the potential application of the proposed experimental methodology to other materials systems and to other types of mechanical damage is discussed.
 
 

Mathematical Comparison Methods to Assess Transfer Functions of Transformers to Detect Different Types of Mechanical Faults

The transfer function (TF) these days is a well-known method to detect different types of mechanical damage in power transformers. The most important mechanical faults mentioned by the authors and researchers, which are most likely to be detected using the TF and occur frequently in transformers, are disc-space variation, radial deformation, and axial displacement. These faults are investigated in this paper using three different similar-size test objects. Since the TF method is a comparative method and the measured results should be compared with the reference results, some mathematical methods are studied to compare different TFs. A complete fault detection, which means determining the type, location, and level of the faults by using TF analyses is the main aim of this paper.

Design and development of a new device for measuring susceptibility to impact damage of fresh produce

Bruising is the most common type of mechanical damage affecting fresh horticultural produce. Several mechanical devices have been reported in the literature for assessing fruit susceptibility to bruising. However, a major limitation of existing devices is the lack of objective measure of the rebound height, which is required to determine the actual impact energy absorbed during damage. In the present study, a new device was designed and developed for objective determination of the rebound height during a pendulum test for bruise susceptibility of whole produce specimens. Using a video camera as an objective benchmark, the new device compared favourably better than subjective visual assessment of the rebound height. The new device provides a simple and cost‐effective tool for fruit impact damage research and education.

Test Method to Evaluate Bruising During Impacts to Apples and Compare Cushioning Materials

Abstract Developing simplified and accurate test methods to quantify and compare performance of impact levels to sensitive produce is a challenge. Despite a variety of packaging options available today, bruising damage is commonplace for post-harvest apples throughout the supply chain. The major sources of bruising are compression, impact, or vibration forces. Understanding where these forces occur can help reduce this type of mechanical damage to apples. The purpose of this study was to investigate the impact characteristics of foam net and corrugated board when applied as wrapping for individual apples. Two grades (count numbers 80 and 100) of “Fuji” cultivar apples imported to Thailand from China were studied. A simple ballistic pendulum test device was developed to measure bruise volume to impact energy relationship. A linear relationship for both types of apples was observed. Bruise volume occurrence probability and impact energy relationship fitted by linear regression were created for cushioned and bare apples. Absorbed energy of various cushioning materials was also calculated under compressive forces.

Some factors affecting the in-soil load–strain behaviour of virgin and damaged nonwoven geotextiles

This paper presents a study on the tensile response of virgin and damaged nonwoven geotextile tested in isolation under different conditions of confinement. Five geotextiles, four confinement conditions and different types of mechanical damage were investigated. The influences of the intrusion of soil particles and the shape of these particles on the load–strain relation of the geotextiles were also examined. The results obtained show that confinement reduces the detrimental effects of mechanical damage on the tensile behaviour of nonwoven geotextiles. The amount and shape of the soil particles that intrude the geotextile pores also influence the tensile stiffness. The results show the potential of nonwoven geotextiles as reinforcement for reinforced soil structures of low to moderate sizes where the use of stiffer reinforcements may not be necessary or may be cost-prohibitive.

Effect of defoliation on onion crop yield

Results of five trials to determine the effects of different defoliation treatments on onion (Allium cepa L.) crop yield carried out in southern Navarre, in the Central Ebro Valley (Spain) are presented. Yield losses caused by defoliation levels of 0, 33, 66, and 100% inflicted using shears at different plant growth stages were evaluated. The results demonstrated a relationship between yield loss, the defoliation treatment applied, and plant phenological stage. Onset of bulb formation was the most critical growth stage for determining the effect of defoliation on the yield, and yield losses increased with increasing the defoliation treatment. The results were employed to calculate a set of regression equations used in turn to construct curves applicable in evaluating final crop yield losses in onions due to defoliation from such causes as hail storms, wind, insect attack, and other types of mechanical damage.

Effect of σ phase on pitting corrosion of 22-5 duplex stainless steel

AbstractThe effect of σ phase content on the pitting potential of 22-5 duplex stainless steel has been investigated in aqueous solutions of O·6M NaCl, with and without nitrogen purging, at both room temperature (22°C) and 80°C. A scratching technique was used to simulate the type of mechanical damage that may occur during service, resulting in localised attack due to disruption of the passive film, particularly in chloride containing environments. The amount of σ phase in the test specimens was varied up to a maximum of 18% by thermal treatment at 850°C for periods of time of up to 3 h to simulate microstructural changes due to welding. The test results showed that σ phase markedly decreases the pitting potential of 22-5 duplex stainless steel at both 22 and 80°C. Furthermore, the extent to which σ phase reduced the pitting potential was found to be strongly temperature dependent, being more pronounced at the higher temperature. Indeed, the increase in test temperature had a greater effect on the pitting ...