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Diplomska naloga opisuje preračun valjev, ki so del kontinuirnega papirnega stroja v podjetju Papirnica Količevo d.o.o. V nalogi je predstavljen celoten postopek od preučevanja obstoječe dokumentacije in računalniškega modeliranja valjev do numeričnega preračuna po metodi končnih elementov. V nadaljevanju je izveden še analitični preračun kritičnih mest in določitev faktorjev varnosti. Vzporedno s praktičnim delom naloge je predstavljeno tudi teoretično ozadje, ki pripomore k razumevanju vsebine izvedenega preračuna. Na koncu naloge so predstavljeni rezultati obeh izvedenih metod (napetosti in pomiki) za vsak valj posebej. This diploma work describes the calculation of rollers, which are part of a continuous paper machine at the company Papirnica Količevo d.o.o. The thesis presents the whole process from the study of the existing documentation and computer modelling of the rollers to the numerical calculation according to the finite element method. Furthermore, analytical calculations of critical sites and determination of safety factors have been carried out. In parallel with the practical part of the task, the theoretical background is also presented, which helps to understand the content of the performed calculations. At the end of diploma, the results of both performed methods (stress and strain) are presented, separately for each roller.

The aim of this research is to develop a physical model useful for measuring the influence of ageing, temperature and water content on the high voltage behavior of oil-paper insulation. The insulation model, made in accordance with the instrument transformer design practice, is placed in a specifically designed capsule in which those parameters can be controlled. All the parts of the capsule were electrically optimized using finite element method-based software. A procedure for insulation preparation that quantifies the water content has been developed. The partial discharge tests verify the applicability of the designed capsule. Thermal testing verifies the model’s useful temperature range up to 120 °C.

Understanding heat transfer in corrugated fibreboard is important to the design of more effective packaging for industries which involve the freezing and chilling of food. In this work the thermal conductivity of papers which compose corrugated fibreboard were measured and used to validate finite element models of heat transfer in fibreboard. The results showed paper to be highly anisotropic, with thermal conductivity in the machine and cross machine directions being almost an order of magnitude larger than in the thickness direction. The finite element models showed good agreement with experimental results and demonstrated that the majority of heat transfer in corrugated fibreboard is though the fluted medium. Based on the finite element models, simple models for the prediction of the thermal performance of corrugated board were evaluated and shown to be very effective in reproducing the results of the more complex finite element methods. These simple methods can be used to perform corrugated fibreboard design calculations, and the models with and without radiation can be used to provide estimates of the lower and upper bounds of the thermal resistance for a given board design.

The finite element model for paper honeycomb was constructed, and the finite element method of out-of-plane compression for the paper honeycomb was studied. Then four kinds of paper honeycomb with different structural parameters were simulated and analyzed using finite element software ABAQUS. Moreover, the results obtained from finite element method were verified based on the existing theoretical research results and experimental results, respectively. The results show that stress–strain curves obtained from finite element method clearly show the four deformation stages of the paper honeycomb under out-of-plane compression, which is basically consistent with the trend of the typical curve. The values of initial peak stress, plateau stress and densification strain are close to the theoretical results. The stress–strain curves and deformation contours coincide with experiments well. The differences of initial peak stress σpk, plateau stress σpl and densification strain εD between theoretical, finite element method and experimental results are less than 15%. Therefore, the finite element method can be used to analyze the stress–strain curves and deformation characteristics of paper honeycomb. In addition, the results also show that the thickness of specimen has little effect on the stress and strain. However, people often prefer to use the thicker paper honeycomb to get better cushioning effect in practical applications, which was explained.

Papirnica Količevo Karton d.o.o. želi povečati svojo zmogljivost delovanja papirniških strojev. Stroji in strojni deli bodo zato posledično veliko bolj obremenjeni pod novimi pogoji delovanja. V diplomskem delu smo prikazali nosilnost valjev papirniškega stroja pod novimi obremenitvami in opisali tehnologije izdelave papirja, ki jih uporabljajo v papirnici Količevo. S pomočjo računalniškega programa Solidworks smo naredili geometrijske modele po načrtih, ki jih je posredovalo podjetje. Simulacije valjev smo izdelali pod novimi obremenitvami, ki jih je posredoval naročnik. Simulacije valjev so narejene s pomočjo programske opreme Abaqus in so izdelane po metodi končnih elementov (MKE). Naredili smo tudi analitični preračun valja. Na koncu je prikazana še primerjava rezultatov, podani pa so tudi faktorji varnosti za posamezen valj papirniškega stroja. Paper Mill Količevo Karton d.o.o. would like to increase the production capacity of their paper machines. The machines and their components will be experiencing more load with these new conditions. In this diploma we showed the paper machine rollers' capacity with new load and described the technologies which are used for paper making in the paper mill Količevo. With help of the application Solidworks we made geometric models in accordance with the plans we acquired at the company. The simulation of rollers was done with new load. The roller simulation were carried out with the finite element method, with help of the Abaqus application. We also did an analytical conversion of the roller. At the end we presented the comparison of results. We also presented safety factors for individual paper machine rollers.

The frequency domain spectroscopy (FDS) of the transformer oil-paper insulation can be simulated by using the finite element method (FEM). However, the effect of nonuniform aging on calculation results has not been included in previous simulation models. Given this issue, a novel simulation model including non-uniform aging is reported. In the present work, the oil-paper samples with various aging degrees are prepared to develop the composite structure of the oil-paper system. Then, the simulation models are constructed based on FEM. The comparison of measured FDS and simulated FDS is used to verify the feasibility of the proposed model. Present findings prove that the proposed model could predict the FDS of the transformer oil-paper insulation under non-uniform aging, which might be utilized to analyze its dielectric response property under non-uniform aging conditions.

Eco-friendly products have gained importance in recent years. The paper bottle is a sustainable packaging solution for carbonated beverages. The moulding process is a two-stage process. At first, pulp is poured in the forming mould and fibers are formed in the desired shape. Wet bottle is then transferred to the drying mould to remove bound water. The drying process makes use of an inflatable core, which not only prevents the shrinkage of fibers but also helps in attaining good fiber compaction. Preliminary investigations reported uneven fiber compaction in changing curvatures and sharp corners. A cause of uneven thickness distribution in the geometry is uneven compaction pressure during core expansion. A FEM approach is developed to predict the occurrence of non-conformities in the bottle. Hyperelastic core material is modelled using Mooney-Rivlin material model from the elastic strain density function. The model can be used to optimize the core shape, thus developing a robust tooling solution.

Paper materials have a long history of use as a packaging material, although traditional paper-based packaging is limited in its shape, complexity, and design. In order to better understand the deformation and failure mechanisms during 3-D forming, two experimental studies of paper materials have been conducted. Furthermore, constitutive modeling combined with explicit finite element modeling have been validated against numerous experimental setups and utilized to develop further understanding of 3-D forming processes. Two experimental studies were necessary to further investigate and model the 3-D formability of paper materials. The combined effect of moisture and temperature on the uniaxial mechanical properties of paper was investigated, providing new insights into how moisture and temperature affect both the elastic and plastic properties of paper materials. Furthermore, the in-plane, biaxial yield and failure surfaces were experimentally investigated in both stress and strain space, which gave an operating window for 3-D forming processes as well as input parameters for the constitutive models. The constitutive modeling of paper materials and explicit finite element modeling were directed towards two 3-D forming processes: deep drawing and hydroforming. The constitutive models were calibrated and validated against simple (typically uniaxial) mechanical tests, and the explicit finite element models (which utilize the developed constitutive models) were validated against 3-D forming experiments. Hand-made papers with fibers partially oxidized to dialcohol cellulose, which has greater extensibility than typical paper materials, was furthermore characterized, modeled, and 3-D formed as a demonstration of the potential of modified paper fiber products for 3-D forming applications. Papper har länge framgångsrikt använts som förpackningsmaterial, men traditionella pappers- och kartongförpackningar är begränsade i form och design. Två experimentella studier har utförts för att få bättre förståelse för deformations- och brottmekanismer under 3D formning. Resultat från konstitutivmodellering i kombination med explicit finit element modellering har validerats mot ett flertal experimentella uppställningar och använts för att utveckla bättre förståelse för 3D formningsprocesser. Två experimentella studier var nödvändiga för att ytterligare undersöka och modellera pappersmaterials 3D formbarhet. I den första undersöktes den kombinerade effekten av fukt och temperatur på pappers enaxliga mekaniska egenskaper, vilket gav nya insikter om hur fukt och temperatur påverkar både de elastiska och de plastiska egenskaperna hos papper. I den andra har biaxiella (i planet) flyt- och brottytor undersökts experimentellt i både spännings- samt töjningsrymden, vilket gav ett processfönster för 3D formningsmetoder samt ingångsparametrar för de konstitutiva ekvationerna. Konstitutiv modellering av pappersmateriel samt explicit finit element modellering riktades mot två 3D formningsprocesser: djupdragning och hydroformning. De konstitutiva modellerna kalibrerades och validerades mot enkla (oftast enaxliga) mekaniska experiment, och explicita finita elementmodeller (som utnyttjar de utvecklade konstitutiva modellerna) validerades mot 3D formningsexperiment. Handark med fibrer delvis oxiderade-reducerade till dialkohol cellulosa, som har större töjbarhet än andra pappersmateriel, har dessutom karakteriserats, modellerats, samt 3D formats som en demonstation av potentialen hos modifierade pappersfiberprodukter i 3D formning. QC 20170104

Esta tese objetiva apresentar um método inovador concebido para estudar como ocorre o fenômeno de migração de umidade no interior de sistemas isolantes papel-óleo de transformadores de potência. A ferramenta é composta por: a) um modelo matemático bidimensional, que representa a dinâmica da umidade no conjunto papel-óleo contemplando variações no carregamento elétrico, e que foi desenvolvido utilizando ferramental matemático, estudos existentes e a experiência de especialistas/analistas; e b) um método de classificação desenvolvido para estudar alguns dos efeitos nocivos da umidade em transformadores de potência, considerando a possibilidade de formação de bolhas e de água livre. O ineditismo da tese é composto por um método numérico, consistido em uma metodologia de cálculo que contempla a utilização do método dos elementos finitos - em duas dimensões - aplicado aos conceitos de transferência de massa e modelagem térmica do carregamento do transformador, considerando as diferenças de temperatura entre dois enrolamentos. Além disso, a novidade da metodologia de classificação consiste na criação de: a) um sistema de classificação para o conjunto transformador – carregamento elétrico em cinco níveis, de “A” a “E”, com as respectivas ações recomendadas; e b) uma análise que envolve a variação dos diferentes níveis de carregamento aplicados ao equipamento. Esta tese contribui com a literatura ao fornecer uma ferramenta eficaz, implementada em software, que fornece subsídios para a tomada de decisão da equipe de manutenção, quando da ocorrência de fenômenos e condições desfavoráveis ​​que podem afetar criticamente a vida útil dos equipamentos, em especial o seu isolamento. Esta tese apresenta ainda alguns estudos de caso de transformadores em operação, em condições reais de carga, em que a validação dos dados é realizada através da comparação dos resultados obtidos com a coleta e análise de amostras de óleo, tanto por métodos laboratoriais quanto por uso de dispositivo de monitoramento. Portanto, este trabalho é útil ao apoiar na classificação e diagnóstico em transformadores de potência, através da predição dos níveis de umidade no sistema isolante papel-óleo, auxiliando a evitar falhas nestes equipamentos e prejuízos aos proprietários dos transformadores e consumidores de energia supridos por estes. This thesis aims to present an innovative tool designed to study how the phenomenon of moisture migration occurs inside insulating paper-oil systems of power transformers. The tool consists of a two-dimensional mathematical model, representing the dynamics of humidity in the oil-paper set and including the variations in electrical charging, which was developed using mathematical tools, existing studies, and the experience of specialists/analysts. Furthermore, this study includes a classification method developed to investigate some of the harmful effects of moisture in power transformers, considering the possibility of bubbles and free water formation. The novelty of this numerical method consists of a calculation methodology that contemplates the use of the finite element method - in two dimensions - applied to the concepts of mass transfer and thermal modeling of the transformer loading, considering the temperature differences between two windings. Additionally, the classification method includes the creation of: a) a categorization system for the coupling of a transformer and electric charging in five levels, from “A” to “E”, with the respective recommended actions; and b) an analysis that involves varying the different levels of loading applied to the equipment. The contribution of this work is an efficient method, implemented via a computational algorithm, which provides support for the maintenance team's decision making when unfavorable phenomena and conditions occur that can critically affect the useful life of the equipment, especially its insulation. This thesis presents some case studies of transformers in operation, under real load conditions, in which the data validation is performed through the comparation of obtained data with experimental collection and analysis of oil samples and the results of monitoring device. Therefore, this work is useful in supporting the classification and diagnosis of power transformers, through the prediction of humidity levels in the oil-paper isolating system, assisting on failure prevention in this equipment and capital loss to the owners of the transformers and consumers supplied by these.

As a basic mechanical component, the sealing ring is widely used in industrial, aerospatial, and other fields. In this study, an elastic metal C-shaped sealing ring with a wave structure was taken as an example, and its performance was analyzed theoretically and measured experimentally. First, an experimental study was performed on the C-ring seal. The proposed method for experimental measurement of the contact stress of the C-ring seal involved innovative use of a universal electronic testing machine and pressure sensitive paper, in conjunction with the hue&ndash, saturation&ndash, brightness (HSB) method. Based on the discoloration of the pressure sensitive paper after contact stress, computer software was used for analysis, the discoloration was digitized, and the contact stress was established. Second, a theoretical calculation model of the C-ring seal was established using ANSYS software, and a finite element theoretical calculation of the mechanical properties of the sealing ring was established. Finally, the contact stress results were compared with the model calculation results of the C-ring seal. The error between the two was small (4.8%), which proved the validity of the calculation model and the scientificity of the experimental method.

As a non-intrusive measurement method, frequency domain spectroscopy (FDS) is widely used to diagnose the global defects (such as aging and dampness) of the insulation body in power equipment. However, the FDS method can only map the holistic dielectric response (DR) characteristics of composite oil-impregnated-paper (OIP) insulation that usually comprises both the insulation paper and oil. Under irregular insulation structure, the DR of each dielectric cannot be simply distinguished, which is unconducive to detect the insulation weakness therein. In this paper, a novel inverse problem model to analyze the separate DR of each dielectric within a compound insulation structure is proposed. Built on the modified Cole-Cole formula, the inverse problem is solved by an optimization process which combines the finite element method and GA-LMA numerical algorithm, and the dielectric variables of insulating oil and paper are back-calculated respectively. By comparing the error of the measured and reconstructed FDS traces, it is evidenced that the proposed model of DR inverse problem and its solution method are suitable for FDS measurements, which signifies new indications for refined state evaluation of OIP insulation by enabling inspecting the separate DR information of each dielectric within a real-life complex insulation structure.

Bushing is the most important part of transformer to connect external component. Bushing fault is one of the prime reasons causing transformer faults. Moisture is an important factor leading to aging of bushing insulation, so it is necessary to evaluate the moisture content of bushing. In the current research, it can confirm whether the oil-paper insulation bushing is uniform damp. But there is no research related to the moisture location of oil-paper insulation bushing. We use Comsol software to carry out a simulation study of the finite element analysis method for nonuniform damp bushing. And the distribution characteristics of hydronium ions and hydroxide ions under electrode polarization can be obtained from the simulation analysis. In this paper, the polarization and depolarization current (PDC) experimental platform was set up and models of nonuniform damp bushings were made. The position information of the high-moisture capacitive screen can be obtained through two different wiring methods. The validity of the method can be verified by the distribution law of hydrolysis ions in this simulation.

The research hypothesis states that the impregnation of the honeycomb paper core of lightweight sandwich panels with modified starch, sodium silicate and epoxy resin (LiquidWood&reg, ) resin has a significant effect on its elastic properties. In this study, a recycled paper was used in three thicknesses, seven types of cell shapes, including two after numerical optimization and three types of impregnating agents. The method of digital image analysis determined the elastic constants of manufactured paper cores, which were subjected to axial compression in two directions. Based on the experimental results, elastic constants of the cores were calculated and compared with the results of numerical calculations. It has been shown that each of the impregnating solutions used improved the stiffness of the paper core. The best results were obtained for LiquidWood&reg, epoxy resin and modified starch. An important parameter of cell geometry affecting their rigidity is the angle of the cell wall &phi, as well as the arrangement of the common cell wall in relation to the direction of load. The numerical models developed were positively verified.

Uniform standard in the structural design for insulated tubular bus is not available both at China and abroad, and there are few reports about insulated tubular bus, which causes a waste of resources and even leads to grid failure. In this paper, epoxy/paper composites insulated tubular bus was investigated and a two-dimensional model was preferred in the simulation due to the axial symmetry of insulated tubular bus. The distribution of electric field and temperature in composite insulated materials were studied with the changes of the diameter/thickness of copper pipe and the thickness of insulation materials. According to the results simulation results, the structure of insulated tubular bus was optimized, the thickness of copper pipe conductor and insulation had been greatly reduced. Compared to the non-optimized initial structure, the amount of copper pipe conductor used for the optimized insulated tubular bus was reduced by 48%, the amount of insulation materials were reduced by 52.5%, and the current density of copper pipe conductor increased by 92.2%.

The moisture-induced degradations during the use of paper are of growing concern for the existing paper materials stored in libraries, archives and museums. Knowing the moisture profiles is therefore a primary step in order to understand paper deterioration and give an assessment of degradation rate of library collections in their preservation. In this paper, the theoretical models based on 2-D scanning electron microscope real image microstructure were established for describing moisture transport in paper sheet in response with external humidity and the moisture diffusion profiles. The acid-catalyzed hydrolysis kinetic in combination with moisture diffusion theory gave the complementary explanation for the time-dependent natural aging process of a paper sheet and book stacks. The differential equations were solved by a numerical approach based on the finite element method implemented in commercial COMSOL Multiphysics. The 2-D simulation results, with a mesh based directly on SEM characterization of microstructure, could show the equilibrium moisture contents and the degradation rates as a function of relative humidity in cellulose pores and cellulose fibers across the transverse section of paper. For the stacks composed of books, the air gaps between the books provided convenient channels for diffusion and transport, accelerating the moisture transport process in the book stacks.

Paper-like electronics with thin multi-layer structures, which can be repeatedly bent and twisted like paper, are promising for diverse innovation application. Employing surface-mounted flexible strain sensors is a general way to monitor the bending characteristics of each layer inside paper-like electronics, however, the deviation of measured strain will reach up to 15% on account of the layer-to-layer interface sliding, neutral axes offset resulted from the extra effect of the flexible strain sensor. Here, we proposed a precise measurement method to evaluate the surface bending strain of paper-like electronics by using flexible sensors. In combination with the effects of the thickness, length, etc, a strain compensation model has been established to compensate the measurement deviation. Meanwhile, a slip failure model has been developed to guide the design of the sensitivity unit within the non-sliding area of the flexible sensor. Validated by finite element analysis and experiment, the bending strain of paper-like electronics (eg., ∼50 μm) can be evaluated much more accurate compared to the frequent access one. The newly-proposed method provides a powerful basis for further research of paper-like electronics.

In order to study the nonuniform aging of the transformer main insulation, this paper designs an experiment and carries out frequency domain dielectric spectroscopy (FDS) testing and conductivity measurement to obtain material performance parameters required for simulation. Using the Comsol simulation software, a two-dimensional simulation model of the main insulation inside the transformer was established, and the finite element analysis in the frequency domain was carried out. The differences of field strength distribution, current density mode and space charge density between the models under uniform aging conditions and those under nonuniform aging conditions were compared and analyzed. Compared with the uniform aging, at low frequencies, nonuniform aging causes that high electric field strength is concentrated on the outermost insulating pressboard; the current flow path changes, and most of it flows through the oil gap-barrier; the accumulation position of free carriers changes.

Capacitive pressure sensors have several advantages in areas such as robotics, automation, aerospace, biomedical and consumer electronics. We present mathematical modelling, finite element analysis (FEA), fabrication and experimental characterization of ultra-low cost and paper-based, touch-mode, flexible capacitive pressure sensor element using Do-It-Yourself (DIY) technology. The pressure sensing element is utilized to design large-area electronics skin for low-cost prosthetic hands. The presented sensor is characterized in normal, transition, touch and saturation modes. The sensor has higher sensitivity and linearity in touch mode operation from 10 to 40 kPa of applied pressure compared to the normal (0 to 8 kPa), transition (8 to 10 kPa) and saturation mode (after 40 kPa) with response time of 15.85 ms. Advantages of the presented sensor are higher sensitivity, linear response, less diaphragm area, less von Mises stress at the clamped edges region, low temperature drift, robust structure and less separation gap for large pressure measurement compared to normal mode capacitive pressure sensors. The linear range of pressure change is utilized for controlling the position of a servo motor for precise movement in robotic arm using wireless communication, which can be utilized for designing skin-like structure for low-cost prosthetic hands.

In order to satisfy the demands for both safety and global warming reduction, a high-strength seismic reinforced steel bar is required in the structural steel market. Recent developments in computational thermodynamics and related application software have made it possible to design a suitable material as well as support engineers of steel manufacturing companies in the production of the designed material with minimum benchmarks in practical operations. This paper reports our recent success in developing grade 600 MPa reinforced steel bars for seismic safety in South Korea. First, conventional alloy design based on CALPHAD-type computational thermodynamics was carried out. For this purpose, a typical alloy system of Fe-0.30C-0.23Si-1.37Mn-0.14V-0.22Cu (in wt%) was selected, and thermodynamic and kinetic calculations were carried out using MatCalc and JMatPro software. Second, in order to reduce V content in the steel for economic reasons, a cooling process designed using finite element (FE) simulation based on the thermodynamic database was performed. For this application, Fe-0.34C-0.22Si-1.34Mn-0.04 V (in wt%) alloy was chosen, and the FE software ABAQUS was applied for modeling the TempCore process. The mechanical properties of the steel products with a diameter of 32 mm produced based on the simulated results satisfy the required properties for grade 600 MPa seismic reinforced steel bars.

Damage detection and localization in civil engineering constructions using dynamic analysis has become an important topic in recent years. This paper presents a methodology based on non-destructive detection, localization and quantification of multiple damages in simple and continuous beams, and a more complex structure, namely two-dimensional frame structure. The proposed methodology makes used of Firefly Algorithm and Genetic Algorithm as optimization tools and the Coordinate Modal Assurance Criterion as an objective function. The results show that the proposed combination of Coordinate Modal Assurance Criterion and Firefly Algorithm or Genetic Algorithm can be easily used to identify multiple local structural damages in complex structures. However, the convergence rate becomes slower for the case of multiple damages compared to the case of single damage. The effect of noise on the algorithm is further investigated. It is found that the proposed technique is able to detect the damage location and its severity with high accuracy in the presence of noise, although the convergence rate became slower than in the case when no noise is present. It is also found that the convergence rate of Firefly Algorithm is much faster than that of Genetic Algorithm.

According to metallurgy, a stainless steel material can be characterized by the presence of a minimum of 10.5% alloying element in the form of Chromium, thereby providing excellent resistance to the adverse and corrosive environments. Stainless steels are divided into five families amongst which the Precipitation hardening alloys are characterized based on the heat treatment method deployed. Precipitation hardening, also referred to as age hardening is one of the heat treatment methods used to enhance the strength levels for most of the malleable materials including stainless steels. Custom 465® stainless is a martensitic precipitation hardenable alloy. This alloy can attain an ultimate tensile strength over 1724 MPa and has been a relatively newer addition to the category of Stainless steel under the precipitation hardenable family. This material finds potential interest with the structural members in aerospace, automotive, medical applications. The high strength characteristic and the composition of this alloy translate directly to machining challenges. This review paper summarizes a literature survey on the effect of various alloying elements present in this alloy, development of process parameters for the conventional turning operation on custom 465® alloy and their optimization by the implementation of Design of Experiments through the finite element analysis.

To explore the application of environmental protection material-paper straw board in cold-formed thin-walled steel (CFS) structures and further develop the sheathing system, an innovative CFS framing wall sheathed by paper straw board (CFSSB) is proposed. Eight CFSSB composite wall specimens and one CFS frame without sheathing were tested under monotonic and reversed cyclic horizontal loads to study the shear performance of the CFSSB composite wall. Also, the shear performance of the wall specimens can be obtained. The key parameters include the value of the vertical load and the form of the CFS frame in this experimental program. By analyzing the specimen’s failure forms and failure process, the characteristic values of the bearing capacity, lateral stiffness, ductility coefficient and energy dissipation coefficient are obtained. The results show that the existence of paper straw board and adding diagonal braces to the CFS frame can significantly improve the shear capacity of CFSSB composite walls. The favorable seismic performance of the CFSSB composite wall was demonstrated in the experiment. In addition, a finite element model for CFSSB composite wall is developed using the software package ANSYS. The finite element analysis (FEA) results show a good agreement with the experiment results in terms of failure modes and skeleton curves, which verify the feasibility of the FEA model. Furthermore, extensive parametric analysis was carried out to analyze the factors affecting the shear capacity of the CFSSB composite wall. The FEA results show that the spacing of studs and self-tapping screws greatly influences the shear capacity of walls. Moreover, based on the failure of the screw connections, a formula for calculating the shear capacity of the CFSSB composite wall is proposed. The results of the formula calculation show good agreement with the experiment and FEA results, and it can provide a reference for engineering design.

Ionic polymer metal composites (IPMCs) are a class of soft electroactive polymers. IPMCs comprise a soft ionic polymer core, on which two stiff metal electrodes are plated. These active materials exhibit large bend- ing upon the application of a small driving voltage across their electrodes, in air or in aqueous environments. In a recent work, we presented compelling theoretical and numerical evidence suggesting that ionic polymer membranes exhibit complex multiaxial deformations neglected by reduced-order structural models. Where most beam theories (including Euler-Bernoulli, Timoshenko, and most higher-order shear deformation models) would suggest vanishing through-the-thickness deformation, we discover the onset of localized deformation that rever- berates into axial stretching. Building upon this effort, here we investigate the role of the electrodes and shear on multiaxial deformations of IPMCs. We establish a novel structural theory for IPMCs, based on the Euler- Bernoulli kinematics enriched with the through-the-thickness deformation in the ionic polymer, computed from a Saint-Venant-like problem for uniform bending. While considering boundary conditions that elicit non-uniform bending, we compare the results of this model against classical Euler-Bernoulli beam theory without enrichment and finite element simulations, encapsulating the nonlinear response of the material. We demonstrate that our theory can predict the macroscopic displacement of the IPMC, along with the localized deformation in the ionic polymer at the interface with the electrodes, which are not captured by the classical Euler-Bernoulli beam theory. This work paves the way to the development of more sophisticated structural theories for IPMCs and analogous active materials, affording an accurate description of deformations at a limited computational cost.