Elementary Behaviors Research Articles

Record of albinism in European ground squirrel (Spermophilus citellus) (Rodentia: Sciuridae) in Slovakia

The European ground squirrel is a mammalian species whose populations are declining and has therefore become the target of various conservation projects in recent years. Currently, there are only a few dozen isolated populations in the Central European region. Increased interest in these animals has contributed to the first record of albino specimens of this species. A total of four juvenile individuals from two litters from one colony were observed, and in addition to the documentation itself, elementary behaviour notes were also made. All specimens did not survive to adulthood, confirming the low survival rate of aberrant individuals in the wild.

Influence of different axis-translation techniques using ceramic disks/microporous membrane filters on mechanical/hydraulic behavior of unsaturated soil

Element tests, such as water retention tests and triaxial tests, are efficient and widely used methods for investigating the elementary hydro-mechanical behavior of unsaturated soil. In recent research, discrepancies observed in unsaturated test results using axis-translation techniques (ATTs) with ceramic disks and microporous membrane filters (MM filters) have indicated that misunderstandings might be hiding behind the perceived elementary behavior seen in element tests. In this study, triaxial tests with ceramic disks and MM filters were firstly conducted on specimens of unsaturated completely decomposed granite sand, referred to as Masado in Japan, to compare the influence of different techniques on the test results. Then a soil–water-air coupled finite element-finite difference (FE-FD) method, based on a newly proposed unsaturated/saturated constitutive model coupled with a deformation-dependent water retention curve (WRC), was utilized to simulate triaxial tests as boundary value problems (BVPs) because of the non-uniform deformation of the specimens. Drained/vented triaxial tests showed that the stress–strain relation of Masado is basically the same regardless of the applied technique, while the amount of drainage discharge and degree of saturation during the shearing stage are quite different. The calculated average stress–strain relation basically reproduced a tendency similar to that of the tests. It was also shown from the calculation that the ATT with ceramic disks or MM filters significantly influences the distributions of saturation and stress within the specimens during shearing. It should be emphasized that unsaturated triaxial tests with the ATT are basically BVPs instead of so-called element tests.

МЕТОД ФОРМАЛІЗАЦІЇ ПРОЦЕСУ ПРИЙНЯТТЯ РІШЕННЯ ЩОДО ЗАПОБІГАННЯ НЕБЕЗПЕЧНИХ СИТУАЦІЙ В СИСТЕМІ E-NAVIGATION

The study aims to improve the safety of ship traffic by improving the methods of formalizing the decision-making process for preventing dangerous situations in a single e-navigation concept. The goal is achieved by a clear statement of the problem and the choice of appropriate approaches to its solution. The main stages of the decision-making cycle performed by the navigator in collision prevention are analysed. Particular attention is paid to the operations performed at the decisionmaking stage on the further movement of the vessel. The ship's movement plan is described by models of elementary behaviour, each of which consists of elementary actions represented by a set of fuzzy logic rules for performing a certain subtask. The structure of a system that implements the behavioural approach to decision-making by a navigator is proposed. Emphasis is placed on the need to coordinate vessels when deciding to plan a route based on models of elementary behaviours, and a method for coordinating the planning of the vessel's trajectory is developed. The sequence of stages of the method for coordinating the planning of the ship's trajectory is performed cyclically until the target point of the route is reached. At each stage of the vessel's movement, the navigation obstacles and other vessels entering the area of interest of the navigator are monitored and potential hazards from them are identified. A method for tracing the vessel's movement and existing vessels in the navigator’s interest area has been developed, which allows for predicting the location at subsequent moments and identifying the coordinates of the conflict site where a situation of dangerous proximity occurs. To formalize the areas dangerous for vessel traffic, a method for generating a map of navigational hazards and conflict situations in the navigator’s interest area has been developed, based on a modified method of potential fields. To formally describe the space, only the concept of a potential function is used to represent the space as a matrix of values. The most significant scientific result is the proposed approach to solving the problem of supporting the decision-making of a navigator based on a combination of methods using fuzzy logic and allowed domains, which allows obtaining options for actions that ensure the safety of ship movement in a dangerous situation. Keywords: ship, navigator, collision, navigation situation, navigation systems, e-navigation, tracing method, navigation hazard, navigation hazard map

Merging and diverging operations: benchmark of three European microscopic simulation tools and comparison with analytical formulations

PurposeWe benchmark three European microscopic simulation software’s ability to reproduce congested patterns at merges and diverges by comparing their macroscopic outputs to validated analytical formulations. The capacity drop and, in the specific case of merges, the priority ratio are assessed. At the microscopic scale, the spatial distribution of lane changes at merges is examined.MethodA single reference state is built for all three simulation tools. A point-based diverge and an extended merge are reproduced in the simulation tools. Under traffic conditions ranging from free-flow to congestion, vehicles counts and vehicles trajectories are collected to compute the selected indicators, which help to conclude for the considered reference state.ResultsThe considered simulation tools correctly reproduce the merges and diverges elementary behaviors. However, their default configuration does not, entirely or partially, reproduce the traffic conditions induced by insertions and desertions as predicted by the analytical models.DiscussionThe study could be enriched by including the benchmark of other simulation tools. In addition, the networks studied are elementary and may not reflect completely the traffic situations encountered on the highways.

The Impact of Physical Motion Cues on Driver Braking Performance: A Clinical Study Using Driving Simulator and Eye Tracker.

Driving simulators are increasingly being incorporated by driving schools into a training process for a variety of vehicles. The motion platform is a major component integrated into simulators to enhance the sense of presence and fidelity of the driving simulator. However, less effort has been devoted to assessing the motion cues feedback on trainee performance in simulators. To address this gap, we thoroughly study the impact of motion cues on braking at a target point as an elementary behavior that reflects the overall driver's performance. In this paper, we use an eye-tracking device to evaluate driver behavior in addition to evaluating data from a driving simulator and considering participants' feedback. Furthermore, we compare the effect of different motion levels ("No motion", "Mild motion", and "Full motion") in two road scenarios: with and without the pre-braking warning signs with the speed feedback given by the speedometer. The results showed that a full level of motion cues had a positive effect on braking smoothness and gaze fixation on the track. In particular, the presence of full motion cues helped the participants to gradually decelerate from 5 to 0 ms-1 in the last 240 m before the stop line in both scenarios, without and with warning signs, compared to the hardest braking from 25 to 0 ms-1 produced under the no motion cues conditions. Moreover, the results showed that a combination of the mild motion conditions and warning signs led to an underestimation of the actual speed and a greater fixation of the gaze on the speedometer. Questionnaire data revealed that 95% of the participants did not suffer from motion sickness symptoms, yet participants' preferences did not indicate that they were aware of the impact of simulator conditions on their driving behavior.

Unified discrete‐element approach applying arbitrary undrained loading paths in element testing for granular soils

AbstractThe discrete element method (DEM) is crucial in investigating and modeling the elementary behavior of granular materials under varying loading conditions, especially those that cannot be adequately investigated via conventional laboratory testing. However, the application of the DEM in simulations that involve complex loading paths under undrained conditions is scarce, primarily owing to the inability to maintain a constant‐volume condition. This paper presents a unified discrete element approach that can apply arbitrary loading paths while satisfying the equivalent undrained condition. The proposed method comprises two parts: (1) a novel strategy that determines the virtual pore pressure under complex undrained loading conditions, and (2) an advanced undrained servomechanism that can simultaneously control each stress component independently. Numerical algorithms corresponding to three new undrained loading paths, that is, true triaxial test, rotational shear, and traffic loading path that have never been simulated using DEM are successfully implemented in a unified manner. Macroscale simulation results under these loading paths are qualitatively in good agreement with their experimental counterparts, thereby confirming the practicality and robustness of the proposed approach. Furthermore, in‐depth discussions on the DEM results from these three new loading paths are presented from microscopic perspective.

Advantages, Pitfalls, and Developments of All Optical Interrogation Strategies of Microcircuits in vivo.

The holy grail for every neurophysiologist is to conclude a causal relationship between an elementary behaviour and the function of a specific brain area or circuit. Our effort to map elementary behaviours to specific brain loci and to further manipulate neural activity while observing the alterations in behaviour is in essence the goal for neuroscientists. Recent advancements in the area of experimental brain imaging in the form of longer wavelength near infrared (NIR) pulsed lasers with the development of highly efficient optogenetic actuators and reporters of neural activity, has endowed us with unprecedented resolution in spatiotemporal precision both in imaging neural activity as well as manipulating it with multiphoton microscopy. This readily available toolbox has introduced a so called all-optical physiology and interrogation of circuits and has opened new horizons when it comes to precisely, fast and non-invasively map and manipulate anatomically, molecularly or functionally identified mesoscopic brain circuits. The purpose of this review is to describe the advantages and possible pitfalls of all-optical approaches in system neuroscience, where by all-optical we mean use of multiphoton microscopy to image the functional response of neuron(s) in the network so to attain flexible choice of the cells to be also optogenetically photostimulated by holography, in absence of electrophysiology. Spatio-temporal constraints will be compared toward the classical reference of electrophysiology methods. When appropriate, in relation to current limitations of current optical approaches, we will make reference to latest works aimed to overcome these limitations, in order to highlight the most recent developments. We will also provide examples of types of experiments uniquely approachable all-optically. Finally, although mechanically non-invasive, all-optical electrophysiology exhibits potential off-target effects which can ambiguate and complicate the interpretation of the results. In summary, this review is an effort to exemplify how an all-optical experiment can be designed, conducted and interpreted from the point of view of the integrative neurophysiologist.

Behavior Composition for Marine Pollution Source Localization Using a Mobile Sensor Network

Marine pollution, which can cause damage to marine ecosystems, cut fishery production, and even harm human health, has aroused worldwide interest in recent years. Marine pollution reduction operations can stagnate in the case that the source of the pollution is unknown or hidden. In this paper, we present a novel method for marine pollution source localization using a network of mobile sensor nodes, such as autonomous underwater vehicles equipped with chemical sensors. Traditional reactive control methods can respond quickly to the shape dynamics of a chemical plume; however, they can hardly achieve intelligent cooperation unlike deliberative methods. In this study, we present a behavior composition method that attempts to combine the advantages of reactive and deliberative methods. An upwind-customized crossover operation based on the genetic algorithm was formulated as one of the elementary behaviors. The upwind sprint and movement away from the centroid of the sensor nodes were also modeled as another two elementary behaviors. Different sensor nodes are capable of different simultaneous elementary behaviors, enabling behavior composition in the mobile sensor network during plume source localization. The proposed method was evaluated using a widely used filamentous plume simulation platform, which has been used to facilitate field experiments in real marine environments. Simulation results indicate that the proposed method achieved high time-efficiency and localization accuracy during plume source localization in marine environments.

Measuring cyber secure behavior of elementary and high school students in the Netherlands

School systems may pay attention to the fact that individuals and companies using smart devices are increasingly at risk of becoming victims of cybercrime. The literature on how effective students in developed countries such as the Netherlands are taught about cyber security skills during their school career is scarce. Although curriculum materials are available, scaling up computer science education is behind. Therefore, this study explores to what extent Dutch students develop cyber secure behavior at elementary and high school. A questionnaire was used for self-assessment of cyber security behavior. After the questionnaire was completed, two group interviews were conducted to improve the interpretation of the questionnaire results. The study findings revealed that the Dutch school curriculum hardly pays attention to this topic and that students acquire their online behavior mainly through experience, instructions on the internet, through parents, and through siblings. In addition, many students developed more reckless behavior over time. We recommend that cyber security education should start at elementary school as soon as children begin to use online equipment. A subject that deserves special attention is recognizing phishing emails and phishing websites. The learners should be convinced that risky behavior on the internet may turn against them and against the organization to which they belong.

Elementary behavior of dual-particle composites cemented by self-compacting mortar: Experimental and constitutive modelling

Artificial cementation can effectively increase the modulus and strength properties of granular materials. To characterize and simulate the cementation effect between granules is of great significance for the analysis of cemented granular materials (CGM). The aim of this study is to investigate the elementary behavior of dual-particle composites cemented by self-compacting mortar (SCM) and provide a unit model for the numerical representation of CGM. A specimen preparation procedure of dual-particle composites was proposed to simulate the filling process of SCM through rockfills in practice. A series of uniaxial compression and tension tests were carried out and the effects of influential factors, including the particle size, particle distance and SCM fluidity, were considered. Based on analyses of the test results, a uniaxial constitutive model was proposed for the targeted dual-particle composites. Finally, through finite element implementation of the model and simulation studies of uniaxial compression tests on CGM, the established constitutive model has been effectively verified to be reliable in predicting the deformation and failure properties of CGM.

Predicting secondary school students’ academic achievement from their elementary school performance and learning behaviours: A longitudinal study based on South Korea’s national assessment of educational achievement

ABSTRACT Academic achievement is an important factor strongly related to positive educational experiences that facilitate subsequent learning. Therefore, identifying students who need support at an early stage and promptly providing appropriate intervention play a crucial role in preventing learning deficits. This study examined the longitudinal change in elementary school students’ proficiency status to understand the nature of longitudinal transitions. It explored the feasibility of developing early predictive models for identifying students potentially facing academic difficulties based on information obtained from elementary school. Deep neural network and hierarchical generalized linear models were applied to large-scale national assessment panel data collected within the framework of an accountability system in South Korea. The results showed that although most students maintained their initial proficiency status, a substantial number of students made longitudinal transitions from non-proficiency to proficiency or vice-versa as they progressed from elementary to high school. The predictive models had an acceptable level of accuracy in predicting future academic performance, considering the degree of student mobility across proficiency levels over grades. The study concluded that the predictive models can serve as a starting point to identify students who need assistance and provide educators with a means to intervene promptly.

Analysis of Influencing Factors of Climate Crisis Behavior for Elementary, Middle, and High School Students in Gyeonggi-do: Focusing on the Mediating Effect of Climate Crisis Risk Perception and Ecological Citizenship

본 연구의 목적은 경기도 초·중·고등학생 기후위기 행동의 영향요인을 분석하는 것이다. 구체적으로 학생의 기후위기 행동에 기후위기 위험인식과 생태시민성의 매개효과를 탐색하는 것이다. 이를 위해 경기도의 초·중·고등학생을 대상으로 설문조사를 실시하였고 총 1,173명이 응답하였다. 응답자료를 토대로 기술통계 분석과 구조방정식 모형 분석, 그리고 학교급을 구분한 다집단모형 분석을 적용하였다. 그 연구결과, 첫째, 학생의 기후변화 위험인식과 생태시민성이 기후변화 지식, 교육수준과 기후변화 태도의 관계를 매개하고 있었다. 둘째, 기후변화 지식과 교육수준은 기후변화 위험인식과 생태시민성에 영향을 미치고, 기후변화 위험인식과 생태시민성은 기후변화 태도에 긍정적 영향을 미치고 있었다. 특히 생태시민성은 특정 교과 혹은 창의적체험활동과 같은 일부 교육과정을 통해서 길러지는 것이 아니라 전체 교육과정을 통해서 길러지는 것으로 이러한 연구결과는 기후위기 시대의 교육이 생태시민성을 기르는 방향으로 전환되어야 함을 시사한다.The purpose of this study is to analyze the factors influencing the climate crisis behavior of elementary, middle, and high school students in Gyeonggi-do. Specifically, it explores the mediating effects of climate crisis risk perception and ecological citizenship on students climate crisis behavior. To this end, a survey with a total of 1,173 respondents was conducted of elementary, middle, and high school students in Gyeonggi-do. Based on the response data, descriptive statistics analysis, structural equation model analysis, and multi-group model analysis were applied. As a result of the study, first, students perceptions of climate change risk and ecological citizenship were found to mediate the relationship between climate change knowledge, level of education, and climate change attitude. Second, climate change knowledge and level of education had an effect on climate change risk perception and ecological citizenship, while climate change risk perception and ecological citizenship had a positive effect on climate change attitudes. In particular, it was found that ecological citizenship was not cultivated through a specific curriculum or through such things as creative experiential activities, but through the whole curriculum. This study shows that education in the era of climate crisis should be transformed.

Integrating Interventions for Elementary Students Experiencing Co-Occurring Academic and Behavior Needs

Teachers who work with students with targeted, co-occurring academic and behavior differences require the knowledge, tools, and support for effective interventions across both domains. This article provides a research-informed, three-step process to support teachers in designing and implementing integrated targeted interventions for mathematics and self-monitoring needs in an elementary, co-taught classroom. This strategic approach includes: (a) screening and diagnostic assessment, (b) delivering academic and behavioral strategies and interventions, and (c) monitoring progress to inform instructional decisions. A case example of a second-grade classroom during supplemental small group linear measurement instruction and self-monitoring integrated Tier 2 intervention is provided for context.

Psychological and pedagogical prevention and correction of non constructive forms of behavior of primary schoolchildren

The article provides data from a theoretical analysis of studies of non-constructive forms of behavior of schoolchildren. Over the past few years, domestic and foreign scientists have noted a significant increase in the manifestation of aggressive tendencies in the school environment. An analysis of scientific psychological and pedagogical literature shows that most studies on aggressiveness and aggression, manifestations of violence in the educational environment are devoted to adolescence. If earlier aggressiveness was a characteristic feature of adolescence, then at present manifestations of aggressiveness are becoming relevant already for pupils of primary school age. The problematic field of theoretical and applied research and its relevance is determined by the contradictions between: (a) the need of society indicated at the state level for the implementation of civil and spiritual and moral education of children, on the one hand, and insufficient theoretical and technological development of the problem of psychological and pedagogical prevention and correction of non-constructive forms elementary school behavior; (b) requirements for the formation of civil and spiritual and moral consciousness and the level of its scientific and methodological support in the education system; (c) the possibilities of developing an effective program of psychological and pedagogical prevention and correction of non-constructive forms of behavior of primary schoolchildren and its implementation in practice. The purpose of the psychological research is to develop the theoretical and methodological foundations of the content and practical ways of introducing a model of psychological and pedagogical prevention and correction of non-constructive forms of behavior in younger students. In the theoretical and empirical part of the study, the authors use an integrated methodology, qualitative and quantitative research methods. An integrated approach makes it possible to design and test a model of psychological and pedagogical prevention and correction of non-constructive forms of behavior in younger students. This article presents the results of the search-theoretical stage of the study, which included first grade students (58 people), their parents and teachers. The conducted theoretical and empirical research allowed to generalize well-known research projects on the problem of manifestation of aggression and aggressiveness, which were carried out by domestic and foreign scientists. Develop a program for diagnosing the forms and causes of the manifestation of aggression, aggressiveness and violence in children's school groups; to conduct a primary diagnosis of the severity of individual psychological characteristics of younger students (self-esteem, anxiety and behavioral reactions in critical situations), which cause aggressive reactions in the behavioral repertoire of junior schoolchild

Four Bosons EM Conservation Laws

Electromagnetism is expressed from two basic postulates. They are light invarianceand charge conservation. At this work one extends the Maxwell scenario from macroscopic to microscopic electromagnetism by following the elementary particles electric charge microscopic behavior. It yields a triune electric charge interrelationship. Three charges {+, 0, −} be exchanged through a vector bosons quadruplet. It is called Four Bosons Electromagnetism. A systemic EM physics appears to be understood. Maxwell photon is not enough for describing the microscopic electric charge physics. An extension for electromagnetic energy is obtained. The fields quadruplet {Aµ, Uµ, Vµ±} are the porters of electromagnetic energy. They are the usual photon Aµ, massive photon Uµ and two charged photons Vµ±, A new understanding on EM phenomena has to be considered. A set determinism based on granular and collective fields is developed. A space-time evolution associated to a whole.Conservation laws are studied. The EM phenomena is enlarged to three charges interchanges to {+, 0, −}. Two novelties appear. New features on nonlinear fields acting as own sources and on electric charge physics. Properties as conservation, conduction, transmission, interaction are extended to a systemic electromagnetism. A whole conservation law for electric charge emerges from three charges interwoven. Electric charge has a systemic behavior. Although there is no Coulomb law for zero electric charge, the Four Bosons Electromagnetism contains an EM energy which provides a neutral electromagnetism. Particles with zero charge {Aµ, Uµ} are carrying EM energy. Another consideration is on EM energy being transported by four nonlinear fields. A new physicality appears. The abelian nonlinearity generates fields charges. Fields are working as own sources through mass terms, trilinear and quadrilinear interactions, spin couplings. Consequently the photon is more than being a consequence from electric charge oscillations. It is able to generate its own charge. Introduce the meaning of photonics.Thus, electric charge is no more the isolate electromagnetic source. There are another conservation laws. Fields sources appear through corresponding equations of motion, Bianchi identities, energy-momentum, Noether laws and angular momentum conservation laws. They move EM to a fields charges dependence. Together with electric charge they carrythe electromagnetic flux. Supporting the Ahranov-Bohm experiment of potential fields as primitive entities.

An approach of modelling of the compaction of flax-carbon hybrid stack preforms

A model, based on the Van Wyk model, is developed to predict the compaction behaviour of stack sequence of dry fabric plies, and is used a set of 3 parameters (stiffness k, pressure sensitivity n and initial fibre ratio Vf0) with P = (k(Vf- Vf))n. The method originality is to construct the behaviour law of a complex stack sequence by the assembly of elementary behaviours. Elementary behaviours are identified using initial experimental compaction tests and are linked to the interaction of a fabric ply with its surrounding environment (another fabric ply or the surface of the compressive mould). This proposed modelling approach have been tested on various carbon, flax and carbon/flax hybrid stack sequence, and seems efficient to predict their compaction behaviour. Its validity is limited to the range of stack sequence of a reduced number of plies. With stack sequence made of numerous fabric plies, some new phenomena must be taken into account. In complement we proposed a method to decompose the compaction behavior curve into three stages (rigid body movement of the fabric plies, nesting of the plies, densification). This method is relevant to compare easily some compaction curves and to evaluate the internal strain state of a stack sequence.

A Rationale for a Gamified E-Coach Application to Decrease the Consumption of Sugar Sweetened Beverages.

The design and implementation of applications for behavior change should be preceded by careful analysis of the behavior change process and the target population. We, therefore, present on the basis of a blended research approach a rationale, opportunities and basic requirements for an application that offers a program for reducing intake of sugar sweetened beverages (SSB) by adolescents. This paper discusses the role of e-coaching and gamification as two high-touch design patterns in the behavior change process. Both design patterns aim at supporting the individual in a transformational journey from a current state toward a desired state where the detrimental behavior should be replaced by healthy alternative behavior. First, an elementary behavior scheme is introduced that frames three empirical studies. In the first study (plenary focus groups; n = 13), participants advised to include system recommendations for alternative healthy behavior, stressed the need for personalization of the e-coach and showed strong appreciation for the inclusion of gamification elements. The second study (online survey; n = 249) showed that SSB-intake is highly contextual and that reasons for (limiting) consumption SSB varies greatly between individuals, which the e-coach application should take into account. In a final small-scale pilot study (n = 27), we observed the potential of the inclusion of gamification elements, such as challenges and rewards, to increase compliance to the self-monitoring process of SSB consumption. Building upon these insights and prior studies, we argue that an e-coach mimics the collaborative practice of the program; its main task is to enrich the interaction with cooperative conversational experiences, in particular with respect to the alignment between user and system, motivational encouragement, personalized advice, and feedback about the activities. In addition, we outline that gamification not only has the potential to increase self-monitoring of the target behavior, user engagement, and commitment with the intervention program, but also enables a designer to shift long-term negative outcome of excessive intake in real life to short-term consequences in a virtual environment. In future larger follow-up studies, we advise to integrate the two design patterns within a social network of virtual and human agents that play a variety of competitive, normative and supportive roles.

ANIMALS AS CRIME VICTIMS

Animals often become a subject of criminal attacks. However, their legal status is not well defined. The article is devoted to the analysis of the contradictions between the legal and biological characteristics of animals that have been subjected to criminal action. Today, in civil and criminal law they are considered as things, that is, inanimate objects. At the same time, numerous studies of the elementary behavior of representatives of the fauna show that, they can feel, experience emotions and possess rational abilities. In this regard, it becomes necessary to study further the legal status of animals, especially those who can carry out reasonable activities. The article provides various opinions of scientists on this issue. Attention is drawn to the position of authors who regard animals as a thing, animate objects. The authors’ position is expressed regarding proposals on the criminal legal protection of only vertebrates. The authors conclude that attacks on animals harm the moral principles of society. They propose to consider only mammals and birds as a subject of cruelty to animals.

Effect of workplace spirituality on creative teaching behavior: Intrinsic job satisfaction as a mediator

We explored how workplace spirituality affects the creative teaching behavior of Chinese elementary and secondary school teachers through their intrinsic job satisfaction, according to conservation of resources theory. We used data from 478 teachers to test the hypotheses with structural equation modeling. The results showed that the workplace spirituality scale that we developed had satisfactory reliability and validity. We also found that workplace spirituality had a positive effect on the teachers' creative teaching behavior, and that their intrinsic job satisfaction fully mediated this relationship. Theoretical and practical implications of our findings and directions for future research are discussed.

Strength and failure of an aluminum/PA66 self-piercing riveted assembly at low and moderate loading rates: Experiments and modeling

The self piercing riveting (SPR) process is increasingly used in the automotive industry due to its ability to connect multi-materials for weight reduction considerations. The strength and failure of such multi-material assemblies need to be characterized and modelled for full-scale structural computations. An aluminum/PA66 composite 2-sheet SPR assembly is characterized in pure and mixed tensile/shear single connection Arcan experiments. The peak force and dissipated energy increase with the loading angle. Neither loading velocity sensitivity in the range 0.016mm/s−100mm/s nor Pa66 composite fiber orientation sensitivity are observed. Some failure modes of aluminum-aluminum SPR are observed. Experiments are also carried out on a single hat component with multiple connections for two loading rates: 5mm/s and 1500 mm/s. The maximum forces and dissipated energies slightly increase at 1500mm/s. Both tensile and shear dominated mode mix ratio values are experienced by the connections. A 13 independent parameter SPR connector model is employed to model the metallic-composite SPR joint. It features three b-norm criteria employed for irreversible deformation, maximum force and failure. It can be generated by combining some elementary behaviors of the general connector model of Abaqus. The calibration procedure decouples the pure tensile/shear contributions from the mixed tensile/shear ones. The parameters are identified based on the Arcan tests and validated on the component experiments. The overall comparison between computations and experiments show satisfactory results.