Composite Element Research Articles

Stress-strain state of a composite tractive element with a broken structure due to elastomer shell rheology

Purpose. Establishing a dependency of change in a stress-strain state for a rubber-cable tractive element with broken structure due to rheology of a rubber shell. Methods. Analytical solution of a model of a rubber-cable tractive element with a broken structure due to rheology of a rubber shell. Results. An algorithm for determining a stress-strain state of a rubber-cable tractive element with a broken structure due to rheology of a rubber shell is developed. The suggested algorithm involves splitting the rope into two parts, which allows considering the influence of a dependency of shear modulus on deformations in a form of a broken line constructed of two segments. Splitting the rope in the area of integrity breakage into three or more parts allows considering a more complex dependency of shear modulus on shear deformations. A mechanism of changing a stress-strain state of a rubber-cable rope due to rheology of a rubber shell is established. The local influence of changes in properties of elastic material interacting with a damaged cable on a stress-strain state of a rubber-cable tractive element with a broken structure is analyzed. Scientific novelty. A mechanism of influence of a shear modulus of rubber shell material in the rubber-cable rope (belt) with a cable integrity breakage on stress-strain state of composite tractive element is established to be time-varying and nonlinearly dependent on deformations. Practical significance. Consideration of shell rubber rheology makes it possible to predict a rope stress state considering a non-linear law of changes in properties of rubber during its use and to increase safety and operational reliability of rubber-cable tractive elements. A local change in mechanical parameters does not increase the danger of using a rope with continuity breakages of cables. An increase in lengths of redistribution of forces and displacements requires an increase in length of steps in butt-joint connections.

Orthotropic composite slabs for road bridges

AbstractLarge increases in traffic loads led to extensive fatigue damages to existing orthotropic steel deck slabs of road bridges. Reinforced concrete bridges and conventional composite bridges are less susceptible to fatigue but considerably heavier. The ortho‐composite slab is a lightweight and robust alternative construction method, which retains the advantages of the previously mentioned construction methods, but eliminates their disadvantages. Within the framework of the AiF‐FOSTA research project P1265 [1], the construction of the bridge deck was developed using dowel strips as composite elements with high load‐bearing capacity and fatigue resistance. The principle of area composite with loading of the dowel strips in longitudinal and transverse direction was used. Extensive experimental and structural mechanics studies were conducted, particularly investigating the load‐bearing capacity and fatigue strength of the ortho‐composite slab under local load application. The following article describes the load‐bearing structure of the ortho‐composite slab and the motivation for the research project P1265. It gives an overview of the experimental investigations carried out. Finally, the article presents pilot projects that were carried out to apply the construction method. In further articles on Eurosteel, the experimental investigations and structural‐mechanical calculations are described in more detail (see [2] and [3]).

Mambaleh Nan Talipek Terinspirasi Dari Kegiatan Manganyam Kampia Di Matua Kabupaten Agam

The Mambaleh Nan Talipek dance work departs from manganyam kampia activities in Matur, Agam Regency. The creators chose to transform the woven techniques such as the lipek technique and the twisting technique onto the dancer's body, so that in making the work they are more focused on developing the woven technique into the structure of the dance work by Mambaleh Nan Talipek which is divided into three parts. In the first part, the artist transforms the lipek technique using his hands, feet and body. The second part transforms the weaving technique by using the properties of the cloth and in this part the dancers perform complementary movements. In the third part, the artist shows the woven Kampia into dance. In this section, Kampia is used to show how the results of the two techniques are formed. This work is strengthened by live music and other compositional elements, the methods used in composing this work are methods of exploration, improvisation, observation, and formation. This work is supported by seven female dancers, with cultural themes and non-dramatic types.

Effect of seasonal temperature shifts on body homeostasis, biochemical parameters and chemical composition of green ormer (Haliotis tuberculata) in the Northern Adriatic.

Seasonal responses of green ormer in terms of antioxidant capacity and lipid peroxidation, proximate and fatty acid tissue composition, trace and macro elements concentrations over the seasons were studied in relation to temperature shifts in the Northern Adriatic Sea. Overall antioxidative defenses (SOD, TBARS, TAS, LDH) varied significantly (p<0.001) according to seasons (primarily spring and summer). The proportions of overall SFA were highest in summer. The proportions of MUFA increased in autumn, with significant differences between genders in spring and summer, and spring, summer and autumn for C18:1n7 and C20:4n6. The only fatty acid lacking significant variation between seasons was C22:5n3. Significant overall differences were observed in summer vs. winter samples for As, Ba, Co, Ni, Mn, Pb, Sb, and Se content in soft tissues, however, gender variations were not significant. The data obtained in the study are of utmost importance for the management of this under-investigated species.

Numerical Investigation of a Sustainable Composite Connection

AbstractDuring the last decade there is an increasing awareness towards sustainable construction solutions. The reason of this shift is that the construction sector contributes to approximately 40 % of the global output of CO2 emissions, thus making it essential to act in lowering this high amount. A key aspect in the successful implementation of sustainable construction solutions is the use of construction materials that can be 100% recycled, such as steel, and that come from renewable sources, such as timber. Therefore, the interest in using steel‐timber composite (STC) elements and connections has grown since they can provide a robust alternative construction technique to traditional ones. The aim of this paper is to investigate the structural performance of a bolted STC shear connection using finite element analysis. The connection under study consists of two dahurian larch glulam elements that are bolted to the flanges of an H‐profile steel element by means of four M6 bolts for each timber component. The numerical model has been validated using the results of an experimental study where a pull‐out test of the same connection is performed [1]. Overall, the numerical results have shown good accuracy. The bolt failure has occurred when 47.5 kN of force had been applied. This amount of load is about 12% less than the failure load found in the experiment. The slip of the numerical model has been found equal to 5.4 mm whereas the slip measured in the experiment has been measured equal to 7.5 mm. In addition, the failure mode that has developed in the numerical model is governed by the formation of two hinges on the bolts which coincides to the experimental one. To sum up, the numerical model has managed to capture to a great extent the structural performance of the composite connection as presented in the experimental findings.

Survey and Interview Findings of an Environmental Scan of Perioperative Geriatric Models of Care in Canada.

Best practice recommendations support the implementation of perioperative geriatric care models that tailor to the specific needs of older adults undergoing surgery. The objective of this study was to describe the current proactive perioperative geriatric programs and pathways in Canadian hospitals. A survey of geriatricians, surgeons, and anesthesiologists practicing in Canada combined with phone interviews of a subset of participants were used to determine characteristics of perioperative geriatric pathways or programs including eligibility, team composition, and intervention elements. Analysis of 132 survey respondents and 24 interviews showed 47% (40 out of 85) of hospitals described had elements of a perioperative geriatrics program and 20% had two or more elements. Eleven themes emerged including: how perioperative geriatric care programs built geriatric competencies in other health-care providers; geriatric assessment identified risks not captured in standard perioperative risk assessment; perceived value for patients and the health-care team; delirium prevention was addressed; most programs were reactive; most programs were informal; virtual care may be used to meet demand; successful implementation required system buy-in with collaboration across subspecialties; mechanisms to drive improvement were accountability and data evaluation; few clinicians with geriatric expertise; and other priorities limited program implementation. There were few hospitals in Canada with perioperative geriatric care models and even fewer with elements spanning the entire perioperative pathway. Strengths, weaknesses, opportunities, and threats to inform the implementation and sustainability of perioperative geriatric care in the Canadian context were identified in this national environmental scan.

Структурно-семантические модели простых повторов в английской разговорной речи

The aim of the study is to identify the models of sentences with duplication of sentence composition elements presented in the works of American playwrights. The paper analyzes the main typical models of simple repetitions without explication of additional components in the sentence structure based on the notion of informative-syntagmatic duplication proposed by Professor M. Ya. Blokh within the theory of paradigmatic syntax. The study makes it possible to take a fresh look at the problem of the classical rhetorical figure of repetition, considering it from the perspective of grammar and information theory. The study is novel in that it is the first to highlight the models of simple repetitions at the sentence level and assess their functionality in question-and-answer interaction. As a result of the analysis, it was found that despite the emerging structural and semantic redundancy of the repetition models without modification of duplicated elements, it gives the utterance an emotionally expressive content, serves as a means of logical emphasis for important information and allows solving various stylistic tasks.

Analysis of the Closing Section of Line Chat in Japanese-Korean Contact Situations : Focusing on Closing Patterns, Composition Elements and Expression Forms

Analysis of the Closing Section of Line Chat in Japanese-Korean Contact Situations : Focusing on Closing Patterns, Composition Elements and Expression Forms

Interface adhesion of fresh-on-fresh cast ultra-high performance concrete–normal concrete: Effect and mechanism of pour delay and ambient humidity

The Ultra-high performance concrete (UHPC)-normal concrete (NC) composite element in this study was created using the fresh-on-fresh casting process with NC placed over UHPC. The impact of the pour delay of 0, 25 min, 1 h, 3 h, 7 h, 10 h, and 24 h as well as the placement environment of standard curing and dry indoors conditions on the interface bond strength were investigated. The findings demonstrate that, under standard curing conditions, a suitable pour delay can not only guarantee the interface bond strength but also decrease the dispersion; While when the pour delay exceeds a certain limit, the interface bond strength decreases linearly until the final setting of UHPC. However, in the dry condition, only a short exposure time will lead to a significant decline in the interface bond strength. From the combination result of computerized tomography (CT) and backscattered electron (BSE) test, it is found that the interface bonding is due to the synergistic effect of aggregate interlocking, fiber anchoring and staggered growth of hydration products. While in a dry condition, the evaporation of water led to the formation of a thin hardening layer on the surface of UHPC, which hindered the interaction between UHPC and NC, and finally led to the rapid loss of interface bond strength.

Effects of Additives on the Mechanical and Fire Resistance Properties of Pultruded Composites.

Under high temperatures, fiber-reinforced polymers are destroyed, releasing heat, smoke, and harmful volatile substances. Therefore, composite structural elements must have sufficient fire resistance to meet the requirements established by building codes and regulations. Fire resistance of composite materials can be improved by using mineral fillers as flame-retardant additives in resin compositions. This article analyzes the effect of fire-retardant additives on mechanical properties and fire behavior of pultruded composite profiles. Five resin mixtures based on vinyl ester epoxy and on brominated vinyl ester epoxy modified with alumina trihydrate and triphenyl phosphate were prepared for pultrusion of strip profiles of 150 mm × 3.5 mm. A series of tests have been conducted to determine mechanical properties (tensile, flexural, compression, and interlaminar shear) and fire behavior (ignitability, flammability, combustibility, toxicity, smoke generation, and flame spread) of composites. It was found that additives impair mechanical properties of materials, as they the take place of reinforcing fibers and reduce the volume fraction of reinforcing fibers. Profiles based on non-brominated vinyl ester epoxy have higher tensile, compressive, and flexural properties than those based on brominated vinyl ester epoxy by 7%, 30%, and 36%, respectively. Profiles based on non-brominated epoxy resin emit less smoke compared to those based on brominated epoxy resin. Brominated epoxy-based profiles have a flue gas temperature which is seven times lower compared to those based on the non-brominated epoxy. Mineral fillers retard the spread of flame over the composite material surface by as much as 4 times and reduce smoke generation by 30%.

State Administrative and Contractual Character of Labor Law Relations of Civil Servants

Purpose: The place of labor law relations of civil servants in the system of relations between state administration and labor contract, its theoretical-conceptual and legal basis were analyzed in the article. There were touched upon the elements which combine labor of civil servants in the system of relations of state administration and labor contract character. Theoretical framework: Labor relations of civil servants have complex composition elements. Implementation of these relations in state bodies is one of the main factors which stipulates the complexity of its composition. Another factor includes the possibility of implementation of mainly two constitutional rights of the citizens of the Republic of Azerbaijan – right to work and right to take part in governing the state. Design/methodology/approach: This research uses a type of mixed method. Along with the organization and activity of state power and state administrative bodies in accordance with the legislation, state administrative relations, in accordance with their status and competence, arises in connection with the implementation of the objectives and functions of the state. Public relations forming the subject of legal regulation of civil service relations are the legal model of public relations fixed in the legislation on civil service. Findings: Labor relations of civil servants act as the part of system of civil service legal relations. Here mainly, legal relations on two aspects attract more attention. One of these relations is the legal relations arising on state administration based on the principle of power-subordination. And the other are the legal relations arising on the implementation of the constitutional right to work in state bodies based on the principle of freedom of labor and on the labor contract. The main subject of the both legal relations is civil servants. This aspect combines labor law relations of civil servants in the system of relations of state administration and labor contract character. Research, Practical &amp; Social implications: The state administrative relations are established, changed and terminated in relation with organization and activity of the state government and state administrative bodies in accordance with the current legislation, as well as implementation of missions and functions of the state in accordance with their status and authorities. Administrative relations making the subject of legal regulation of civil service relations are legal model of the administrative relations identified in the legislation on civil service. Originality/value: The civil service is one of the main provision means of implementation of state government and state administration.

Exploring the application of composite materials in ceramic design based on fuzzy numerical analysis

Abstract Compared with traditional monolithic carbide ceramics, Cu-based composite ceramics have the advantages of higher hardness, good wear resistance and oxidation resistance and are a new type of structural ceramics with wide application prospects. This paper first proposes a novel bi-directional freezing technique to construct a three-dimensional long-range ordered layer network hierarchical structure based on the pressure infiltration process. Secondly, a composite finite element model based on fuzzy numerical analysis is proposed for the vibroacoustic analysis of the periodic composite coupled system (PCSAS). Finally, thermal analysis experiments and mechanical property tests verify the effectiveness of Cu-based composites applied to ceramic matrices. The experimental results show that the toughness of Cu-based composite ceramics increases with the increase of TiC content, and the toughness increases from 2.15±0.27Mpa.m1/2 to 4.21±0.25Mpa.m1/2 compared with that of conventional monolithic carbide ceramics. The Cu-based composite ceramics designed in this paper give full play to the advantages of the high strength of ceramic particles and high toughness of metal matrix and develop an effective method to prepare structural metal-ceramic composites. This paper has developed an efficient route for preparing structural metal-ceramic composites, which can provide a reference for materials researchers to develop high-toughness composite ceramics.

Analysis of Picture Composition in Teaching Contemporary Photographic Art

The study of photographic composition is a transitional stage from the basic course to the creative course, and it is required to cultivate students' photographic consciousness and photographic means of expression in the process of teaching composition. Through the description of the basic theory of photographic composition elements, this paper focuses on the three main characteristics of contemporary photographic art picture composition, from what problems need to be solved in photographic picture composition to the elaboration of the connotation and purpose of photographic picture composition, and analyzes the research method and basis of picture composition. The photography course mainly teaches the general rules of picture composition, mainly cultivates students' observation ability and the ability to instantly organize the picture, and requires students to focus on the use of the subject to tell the content of the work, to convey the idea, and to make clear how to make all-round modeling of the subject, so as to lead the viewers' sights to the subject that the photographer wants to express. It emphasizes that picture composition is the process of reproducing the thoughts of the photographer.

Analysis of Steel–Concrete Composite Elements Considering the Branson Equation for Cracking Simulation

Analysis of Steel–Concrete Composite Elements Considering the Branson Equation for Cracking Simulation

Vibration suppression of the blisk based on intentional mistuning of piezoelectric shunt damping patches

In this paper, the finite element model of the mistuned blisk with intentional mistuning of piezoelectric shunt damping patches (PSDPs) is established. In the process of modeling, the piezo-blisk substrate composite element and the substrate thickness variation element are analyzed. Then, compared with the experimental results, the feasibility and accuracy of the finite element model are verified. Finally, the impact of the circumferential position mistuning of PSDPs and piezoelectric shunt parameter mistuning on the vibration reduction of the blisk is analyzed. The results indicate that better vibration suppression effect can be obtained by reasonably designing the mistuned mode of PSDPS.

Physical interaction between MSL2 and CLAMP assures direct cooperativity and prevents competition at composite binding sites.

MSL2, the DNA-binding subunit of the Drosophila dosage compensation complex, cooperates with the ubiquitous protein CLAMP to bind MSL recognition elements (MREs) on the X chromosome. We explore the nature of the cooperative binding to these GA-rich, composite sequence elements in reconstituted naïve embryonic chromatin. We found that the cooperativity requires physical interaction between both proteins. Remarkably, disruption of this interaction does not lead to indirect, nucleosome-mediated cooperativity as expected, but to competition. The protein interaction apparently not only increases the affinity for composite binding sites, but also locks both proteins in a defined dimeric state that prevents competition. High Affinity Sites of MSL2 on the X chromosome contain variable numbers of MREs. We find that the cooperation between MSL2/CLAMP is not influenced by MRE clustering or arrangement, but happens largely at the level of individual MREs. The sites where MSL2/CLAMP bind strongly in vitro locate to all chromosomes and show little overlap to an expanded set of X-chromosomal MSL2 in vivo binding sites generated by CUT&RUN. Apparently, the intrinsic MSL2/CLAMP cooperativity is limited to a small selection of potential sites in vivo. This restriction must be due to components missing in our reconstitution, such as roX2 lncRNA.

A novel GATA2 distal enhancer mutation results in MonoMAC syndrome in 2 second cousins

AbstractMutations in the transcription factor GATA2 can cause MonoMAC syndrome, a GATA2 deficiency disease characterized by several findings, including disseminated nontuberculous mycobacterial infections, severe deficiencies of monocytes, natural killer cells, and B lymphocytes, and myelodysplastic syndrome. GATA2 mutations are found in ∼90% of patients with a GATA2 deficiency phenotype and are largely missense mutations in the conserved second zinc-finger domain. Mutations in an intron 5 regulatory enhancer element are also well described in GATA2 deficiency. Here, we present a multigeneration kindred with the clinical features of GATA2 deficiency but lacking an apparent GATA2 mutation. Whole genome sequencing revealed a unique adenine-to-thymine variant in the GATA2 –110 enhancer 116,855 bp upstream of the GATA2 ATG start site. The mutation creates a new E-box consensus in position with an existing GATA-box to generate a new hematopoietic regulatory composite element. The mutation segregates with the disease in several generations of the family. Cell type–specific allelic imbalance of GATA2 expression was observed in the bone marrow of a patient with higher expression from the mutant-linked allele. Allele-specific overexpression of GATA2 was observed in CRISPR/Cas9-modified HL-60 cells and in luciferase assays with the enhancer mutation. This study demonstrates overexpression of GATA2 resulting from a single nucleotide change in an upstream enhancer element in patients with MonoMAC syndrome. Patients in this study were enrolled in the National Institute of Allergy and Infectious Diseases clinical trial and the National Cancer Institute clinical trial (both trials were registered at www.clinicaltrials.gov as #NCT01905826 and #NCT01861106, respectively).

Design, fabrication and testing of a high frequency broadband hydroacoustic transducer for sonar systems

A high frequency broadband hydroacoustic transducer was fabricated for applications such as small target detection and fine imaging in sonar systems. The utilization of the structure design of multimode coupling theory is employed to expand the operational bandwidth of the transducer by leveraging the characteristics of 1–3 type piezoelectric composites that possess a broad frequency range. Piezoelectric composite sensitive elements of varying thicknesses were developed through optimization of dimensional parameters using theoretical and finite element simulation analyses. These composite sensitive elements were then bonded to a spiral stepped backing to enable lateral stacking, ultimately resulting in the fabrication of a high frequency broadband hydroacoustic transducer. The outcomes of the underwater performance evaluation indicate that the transducer's central frequency is 310 kHz, with a −3 dB bandwidth capable of reaching 100 kHz. The maximum transmit voltage response is 159 dB, while the maximum receive sensitivity is −182 dB. Additionally, the directional beam opening angle of −3 dB at the center frequency is roughly 9°, which effectively broadens the transducer's bandwidth.

An accurate and efficient 4-noded quadrilateral plate element for free vibration analysis of laminated composite plates using a refined third-order shear deformation plate theory

An accurate, efficient and reliable four-noded quadrilateral plate element is developed for the free vibration analysis of laminated composite plates. The element formulation is based on a refined third-order shear deformation plate theory (TSDT) and the quasi-conforming element technique. The equations of motion and the variational consistent mass matrix are derived through Hamilton’s principle. The resulting composite plate element is free from shear locking. Furthermore, both its element stiffness and mass matrices are computed explicitly. The convergence and accuracy of the present element are evaluated by the standard static and dynamic examples of isotropic plates. The accuracy of the computed natural frequencies of laminated composite plates is verified by the examples with various lamination schemes, elastic modulus ratios, aspect ratios and boundary conditions and by the comparison with other results. The effect of the associated boundary conditions in different TSDTs is also evaluated through numerical results. The influence of the higher-order and coupling mass matrices on the frequencies of higher-mode vibration is conducted too. The numerical results clearly demonstrate that the present plate element is not only very efficient but also capable of yielding accurate natural frequencies of both the fundamental and the higher-mode vibrations of laminated composite plates.

Parametric analysis and numerical optimisation of spinach root vibration shovel cutting using discrete element method

Shovelling the soil and cutting the roots is the first step in harvesting the whole spinach plant, which determines the movement state of spinach plants, the state of soil fragmentation and root soil separation force. Therefore, it is necessary to thoroughly study the process of shovelling the soil and cutting the roots. Firstly, micromechanical and macromechanical models of shovel cutting were built. It was induced that vibration shovel cutting was conducive to soil fragmentation and root-soil separation by the theoretical models. Secondly, a vibration shovel cutting mechanism was proposed. In order to study the interaction mechanism of root-soil-shovel, a root-soil composite discrete element model was established and calibrated. Vibration shovel cutting simulation test was carried out based on the model. The effects of three vibration shovel cutting parameters (vibration amplitude, vibration frequency and cutting speed) on the number of bond by bonding (BOND) breakage, root-soil movement law, soil uplift height and root-soil separation in normal vibration, tangential vibration and non-vibration were analyzed. BOND breakage was conducive to spinach aggregation and root-soil separation by simulation analysis. As determined by response surface analysis, the optimal combination of parameters for the maximum number (80363) of BOND breakage and the minimum soil uplift height (19.4 mm) was vibration amplitude of 3 mm, vibration frequency of 40 Hz and cutting speed of 0.3 m/s. Finally, the vibration shovel cutting model was verified experimentally by field tests. This study provides a method to study the interaction mechanism of root-soil-shovel.