Strain Theory Research Articles

A new model of thermo-mechanical actuation for twisted and coiled polymer muscles with initial curvature

The twisted and coiled polymer (TCP) artificial muscle is one type of novel soft actuator for mimicking natural skeletal muscle that can provide large linear and torsional actuation and energy density. Twisting and coiling are the pivotal steps in fabricating TCP muscles. The influence of twisting on the actuation response of TCP muscles has been extensively investigated recently. However, the influence of coiling remains unclear. Based on the finite strain theory, we establish a new thermo-mechanical actuation model for TCP muscles with initial curvature. The theoretical predictions based on the model align well with the finite element simulations, accurately capturing the actuation response of thermally-activated TCP muscles. It is revealed that twisting contributes positively to the actuation, while coiling has a passive effect. Geometrical parameters, such as the helix radius and helix angle, can effectively regulate the actuation performance of TCP muscles. Furthermore, an optimal bias angle is identified that maximizes both the recovery torque and the linear actuation. This study sheds light on the structural optimization design of TCP muscles.

Mixed mode I/II and I/III fracture toughness investigation for preplaced aggregate concrete mixtures: Experimental study and theoretical prediction

AbstractIn this paper, mixed mode I/II and I/III fracture toughness of preplaced aggregate concrete was studied using an edge‐notched disc bend specimen. The results showed the dependency of the fracture toughness value on the mode mixity. The values of modes I, II, and III fracture toughness were obtained to be equal to , , and , respectively. Several theoretical fracture criteria were examined for predicting the trends of experimental data in the tested preplaced aggregate concrete material. The 3D averaged strain energy density criteria provided the best predictions for the KIIIc/KIc ratio. Mixed mode I/III fracture toughness data were between the predicted envelopes of the maximum tensile stress and 3D maximum tangential strain theories. The generalized maximum tangential stress criterion provided accurate predictions for pure mode II and mixed mode I/II fracture data among the investigated mixed mode fracture criteria. By comparing the preplaced aggregate concrete fracture results with those of other types of concrete, it is observed that preplaced aggregate concrete has acceptable and in‐the‐range fracture resistance.

A robust finite strain isogeometric solid-beam element

In this work, an efficient and robust isogeometric three-dimensional solid-beam finite element is developed for large deformations and finite rotations with merely displacements as degrees of freedom. The finite strain theory and hyperelastic constitutive models are considered and B-Spline and NURBS are employed for the finite element discretization. Similar to finite elements based on Lagrange polynomials, also NURBS-based formulations are affected by the non-physical phenomena of locking, which constrains the field variables and negatively impacts the solution accuracy and deteriorates convergence behavior. To avoid this problem within the context of a solid-beam formulation, the Assumed Natural Strain (ANS) method is applied to alleviate membrane and transversal shear locking and the Enhanced Assumed Strain (EAS) method against Poisson thickness locking. Furthermore, the Mixed Integration Point (MIP) method is used to make the formulation more efficient and robust. The proposed novel isogeometric solid-beam element is tested on several single-patch and multi-patch benchmark problems, and it is validated against classical solid finite elements and first-order Lagrange solid-beam element. The results show that the proposed formulation can alleviate the locking effects and significantly improve the performance of the isogeometric solid-beam element. With the developed element, efficient and accurate predictions of mechanical properties of lattice-based structured materials can be achieved. The proposed solid-beam element inherits both the merits of solid elements e.g. flexible boundary conditions and of the beam elements i.e. higher computational efficiency.

Exclusion or Empowerment? A Critical Analysis of Women’s Roles in Somaliland’s Electoral Politics in 2021

This research examines the complex obstacles exclusionary and empowerment factors that impact women’s participation in parliamentary elections in Somaliland. By utilizing qualitative method with in-depth interviews with female candidates from the 2021 elections, the study delves into the intricate relationship between cultural, structural, and psychological exclusion, alongside educational, supportive, and strategic empowerment, in the unique political atmosphere of Somaliland. The results indicate that deeply ingrained cultural norms, entrenched political barriers, and significant financial constraints severely limit women’s political engagement. These barriers are compounded by psychological factors that diminish women’s political aspirations and efficacy. On the other hand, empowerment through higher education, robust supportive networks, and effective strategic planning emerges as key to overcoming these obstacles. The study employs theoretical frameworks such as Strain Theory, Social Identity Theory, and Resource Mobilization Theory to provide a deeper understanding of these dynamics. The implications of this research are far-reaching, suggesting that comprehensive interventions encompassing policy reforms, educational programs, and community dialogues are essential for enhancing women’s political participation. This study not only enriches the academic discourse on gender and politics in understudied contexts but also provides practical recommendations for stakeholders aiming to foster a more inclusive political landscape in Somaliland and similar settings.

FINITE SHEAR STRAIN BASED ON IMAGE ANALYSIS FOR RECTANGULAR SECTION SHAFT WITH LARGE ASPECT RATIO

This paper describes the shearing strain distribution obtained by using image analysis proposed in this study when large torsion is applied to a rectangular cross-section shaft. As is well known, the shearing strain distribution for rectangular cross-section shaft have already been investigated by Saint-Venant. However, since this theory is based on the assumption that torsional angle is relatively small, it is not necessarily rational under large torsion. Therefore, in our previous study, using the image analysis based on the Natural Strain theory, where the commutative law of strain is applicable and the rigid body rotation can be removed accurately from shearing strain component, the shearing strain distributions have been investigated for the rubber shaft having square cross section. In the present paper, these distributions are investigated for a rectangular cross section with a large aspect ratio rather than a square shape. In particular, these distributions on the long side in rectangular cross-section are compared with those on the short sides. Consequently, the difference between the distribution of shearing strain obtained by the image analysis in this study and measurements based on Saint-Venant's theory increases as torsional deformation increases and this tendency is observed particularly on the short side.

FINITE SHEAR STRAIN BASED ON IMAGE ANALYSIS FOR RECTANGULAR SECTION SHAFT WITH LARGE ASPECT RATIO

This paper describes the shearing strain distribution obtained by using image analysis proposed in this study when large torsion is applied to a rectangular cross-section shaft. As is well known, the shearing strain distribution for rectangular cross-section shaft have already been investigated by Saint-Venant. However, since this theory is based on the assumption that torsional angle is relatively small, it is not necessarily rational under large torsion. Therefore, in our previous study, using the image analysis based on the Natural Strain theory, where the commutative law of strain is applicable and the rigid body rotation can be removed accurately from shearing strain component, the shearing strain distributions have been investigated for the rubber shaft having square cross section. In the present paper, these distributions are investigated for a rectangular cross section with a large aspect ratio rather than a square shape. In particular, these distributions on the long side in rectangular cross-section are compared with those on the short sides. Consequently, the difference between the distribution of shearing strain obtained by the image analysis in this study and measurements based on Saint-Venant's theory increases as torsional deformation increases and this tendency is observed particularly on the short side.

일반긴장요인과 화이트칼라 범죄 발생의 상호관계 검증

The purpose of this study is verifying the impact on white-collar crime intentions through applying general strain theory, particularly by categorizing white-collar workers into subordinates, middle managers, and executives, and comparing the differences in criminal intention depends on their job levels. The intention for white-collar crime, specifically focusing on embezzlement, was suggested as The dependent variable. Also, rather than direct measurement about embezzlement, and respondents were prompted to response their behaviors and perceptions in specific situations with suggested crime scenarios The independent variables included strain factors proposed by the General Strain Theory, such as the loss of positive stimuli, failure to achieve goals, and the occurrence of negative stimuli, along with negative emotions. To achieve the goal of this research, data was collected focusing on office, business, and management workers in the metropolitan area. As a result, general strain factors did not affect to the intent for white-collar crime at the executive level. However, it was suggested that the smaller the size of the company, the more significant affect on the intention for white-collar crime. In the case of subordinate and middle management workers, both general strain factors and negative emotions affected significantly to the intention for white-collar crime. Therefore, to counteract white-collar crime, it is requested the differentiated strategies for each job levels. For small and medium-sized enterprises, controls to executives should be strengthened, and for large enterprises or conglomerates, a fair promotion system and adequate economic rewards, such as appropriate wage increasing, should be enhanced to mitigate the feelings of deprivation among lower-level employees and middle managers.

Strain, Anger, and Prison Misconduct: Examining the Impact of Unfair Wages, Broken Social Ties, and Dehumanization

Using the theoretical framework of General Strain Theory, this study examines how each of Agnew’s categorizations of strain are associated with people in prison’s anger and self-reported charges for misconduct. The strains explored include dehumanization (negative stimuli), loss of social ties (removal of positive stimuli), and unfair pay for labor (unjust outcomes). Surveys of 3,531 men and women incarcerated in five different facilities were examined. Each strain is significantly and positively associated with anger. Anger is significantly and positively associated with misconduct. Dehumanization and loss of social ties are significantly and indirectly associated with misconduct through anger in the theoretically expected direction. In sum, strains may foment anger among people in prison resulting in rule breaking.

QuadWire: An extended one dimensional model for efficient mechanical simulations of bead-based additive manufacturing processes

This paper presents the basis of a new mechanical model named QuadWire dedicated to efficient simulations of bead-based additive manufacturing processes in which elongated beads undergoing significant cooling and eigenstrain are assembled to form 3D parts. The key contribution is to use a multi-particular approach containing 4 particles per material point to develop an extended 1D model capable of capturing complex 3D mechanical states, while significantly reducing computation time with respect to conventional approaches. Indeed, 3D models usually require at least 3 to 4 elements across the bead section, which results in fine discretization along the tangential direction to avoid conditioning issues, and therefore very fine mesh of the entire 3D part. In the QuadWire model, the bead height and thickness are internal dimensions, enabling a significantly coarser mesh along the tangential direction. Thus, although the QuadWire has 12 degrees of freedom per material point instead of 3 for classical models, the total number of degrees of freedom is reduced by several orders of magnitude for large parts. The proposed model is classically developed within the framework of the principle of virtual power and standard generalized hyperelastic media (i.e., finite strain theory), which necessitates a thermodynamic analysis. Furthermore, the proposed approach includes native and manageable kinematic constraints between successive beads so that the stress state properly evolves during fabrication. Finite element analysis is used for numerical implementation under infinitesimal strain assumption for the sake of simplicity, and the QuadWire stiffness parameters are optimized so that the mechanical response fit conventional 3D approaches. To validate and demonstrate the capabilities of the proposed strategy, the evolution of displacements and stresses in fused deposition modeling of polylactide is simulated.

A finite strain theory for incompressible rubber-like circular arches with an application

A theory for incompressible rubber-like circular arches, undergoing finite strains and rotations, with an application to the stability of Mooney-Rivlin, doubly fixed, thin beams having initially small circular imperfections under uniformly distributed radial loads, is presented. The essence of considering transverse normal strain is emphasized for an incompressible rubber-like material. The effects of the thickness, initial curvature, and perturbation terms of the pseudo strain components on the buckling loads and central deflections are investigated. The thresholds of buckling are observed to depend on the values of the curvature of the initially imperfect beam for the chosen nonlinear material.

Effect of Welding Gap of Thin Plate Butt Welds on Inherent Strain and Welding Deformation of a Large Complex Box Structure.

In this study, an effective numerical model was developed for the calculation of the deformation of laser-welded 3 mm 304L stainless steel plates with different gaps (0.2 mm, 0.5 mm, and 1.0 mm). The welding deformation would become larger when the welding gaps increased, and the largest deformation values along the Z direction, of 4 mm, were produced when the gap value was 1.0 mm. A larger plastic strain region was generated in the location near the weld seam, since higher plastic deformation had occurred. In addition, the tensile stress model was also applied at the plastic strain zone and demonstrated that a larger welding gap led to a wider residual stress area. Based on the above results, inherent deformations for butt and corner joints were calculated according to inherent strain theory, and the welding formation for the complex structure was calculated with different gaps. The numerical results demonstrated that a larger deformation was also produced with a larger welding gap and that it could reach the highest value of 10.1 mm. This proves that a smaller welding gap should be adopted during the laser welding of complex structures to avoid excessive welding deformation.

The Role of Situational Ambiguity: An Extension of General Strain Theory

ABSTRACT General Strain Theory (GST) posits that strains are likely to be most criminogenic when high in magnitude, viewed as unfair, associated with low social control, and promote pressure or incentive to engage in criminal coping. However, GST ignores other potential characteristics of criminogenic strain that have been particularly salient in explaining decision-making – situational unpredictability and uncertainty. Research suggests that events characterized by uncertainty and unpredictability increase situational anxiety and lead to increased stress, as well as other negative emotions such as anger, frustration, and depression. Therefore, “situational ambiguity” –unpredictability and uncertainty – can be viewed as a situational characteristic of criminogenic strain that has not been considered in prior GST literature. The current paper integrates the concept of situational ambiguity into the GST framework and further discusses the implications of this addition to the overall GST model.

Intimate Partner Abuse and Homicide During the COVID-19 Pandemic: A Situational Action Theory Analysis

During the COVID-19 pandemic, stay-at-home restrictions significantly changed people’s daily lives around the world. Opportunity and strain theories predict this would lead to an increase in intimate partner abuse (IPA), including intimate partner homicide (IPH). This paper applies an alternative theoretical framework—situational action theory (SAT)—to explain mixed findings regarding changes in IPA and unexpected findings regarding (a lack of) changes in IPH. It is argued that SAT may contribute to explaining the impact of stay-at-home restrictions on IPA and IPH in three important ways: 1. by addressing the fact that motivation is necessary but not sufficient for explaining action and better specifying how motivation translates into IPA and IPH; 2. by addressing the fact that people perceive different alternatives for action and better specifying why some people come to see IPA and IPH as acceptable action alternatives; 3. by addressing the fact that exposure affects people differently and better specifying how stay-at-home restrictions shaped people’s activity fields and, in turn, their perceptions and action choices.

‘LOOBAN’: A MULTIPLE-CASE STUDY ON DELINQUENCY OF TEENAGERS SHAPED BY DYSFUNCTIONAL FAMILIES

Young people engage in delinquent behavior. It covers crimes against persons, crimes against things, crimes against public order, and drug offenses. Delinquent behavior is, therefore, an unmanageable activity that affects the community. This research presents the different experiences of three delinquent teenagers whose dysfunctional families shaped them in a community called “Sitio Looban” in the Philippines. This study utilized a qualitative multiple-case study to understand and describe the different stories of each participant-case. The study sought to answer the research questions about the family factors that contribute to the delinquency of teenagers, their delinquent experiences, and their feelings and thoughts as delinquent teenagers. The researchers used an in-depth interview to gather the necessary data from the informants. Within-case and cross-case analysis were used to analyze the data, wherein emerging themes were created to describe the family factors that contributed to the delinquency of the teenagers, which include broken family, poor parenting, home discord vis-à-vis peer influence, child neglect, poor family, and family binge drinking. Emerging themes were also created to discuss the delinquent experiences of teenagers, which involve theft, using counterfeit money, and gambling cheating. There were also emerging themes created to describe the feelings and thoughts of the delinquent teenagers, which include: unconditional love and support, happiness towards friendship, regrets, fear, embarrassment, and hatred and anger. This study supports the Strain Theory and Social Control Theory, which explain that negative relationships with family lead to delinquent behaviors in teenagers. Implications for practice and future researchers are provided in this paper.<p> </p><p><strong> Article visualizations:</strong></p><p><img src="/-counters-/soc/0737/a.php" alt="Hit counter" /></p>

Nonlinear free vibration of pre-buckled PFG micro/nanotubes via nonlocal strain and velocity gradient theory

Nonlinear free vibration of pre-buckled PFG micro/nanotubes via nonlocal strain and velocity gradient theory

COVID-19 Parental Job Disruptions and Adolescent Suicide

ABSTRACT A persistent issue for public health officials, suicide attempts among adolescents have increased in many parts of the United States since the onset of the COVID-19 pandemic. Despite some work examining antecedents of suicide decisions, less is known about how certain experiences – exacerbated by the pandemic – influence adolescents’ propensity to attempt suicide. Using representative data from a sample of Florida adolescents, this study relies on Agnew’s General Strain Theory to investigate how pandemic-related parental job disruptions influence suicide decisions, and whether this relationship occurs indirectly through feelings of anger and depressive emotions. Results indicate that parental job disruptions are positively associated with one’s odds of attempting suicide, with most of this relationship occurring indirectly through depressive emotions.

The Role of Family Structure in Juvenile Delinquency

Purpose: The general purpose of the study was to explore the role of family structure and juvenile diplomacy. Methodology: The study adopted a desktop research methodology. Desk research refers to secondary data or that which can be collected without fieldwork. Desk research is basically involved in collecting data from existing resources hence it is often considered a low cost technique as compared to field research, as the main cost is involved in executive’s time, telephone charges and directories. Thus, the study relied on already published studies, reports and statistics. This secondary data was easily accessed through the online journals and library. Findings: The findings reveal that there exists a contextual and methodological gap relating to family structure in juvenile diplomacy. Preliminary empirical review revealed that that family structure significantly influences adolescent engagement in delinquent behaviors, with adolescents from single-parent households or non-traditional family arrangements exhibiting higher rates of delinquency. Research highlighted the mediating role of factors such as parental supervision and positive peer relationships, along with cultural variations in this relationship. Qualitative insights underscored the unique challenges faced by adolescents from non-traditional family structures, emphasizing the importance of tailored support. Overall, the findings underscored the need for context-specific interventions and policies to address juvenile delinquency, informed by a comprehensive understanding of family dynamics and socio-cultural factors. Unique Contribution to Theory, Practice and Policy: Social Learning theory, Strain theory and Social Control theory may be used to anchor future studies on the role of family structure in juvenile delinquency. The study provided recommendations with significant contributions to theory, practice, and policy. It advanced theoretical understanding by highlighting the complex interplay between family dynamics and delinquent behavior, contributing empirical support for existing theoretical models. The study recommended the development of family-centered interventions to strengthen parental supervision and support networks, promote positive peer relationships, and address systemic factors contributing to family stressors. Policy implications included initiatives to support family well-being, invest in evidence-based programs, and integrate findings into broader social policies. Collaboration across sectors was emphasized to implement comprehensive approaches, and the need for continued research to deepen understanding and inform targeted interventions was underscored.

The development and evolution of ethics review boards – Israel as a case study

Although well established in developed countries, Ethics review boards in the academia, and specifically for social and behavioral sciences (SBS) research, is a relatively new, and still a controversy inducing endeavor. This study explores the establishment and functioning of ERBs in Israeli academia, serving as a case study for the challenges and progress made in ensuring ethical research practices in non-medical related spheres. A purposeful sample of 46 participants was selected, comprising ERB current or past members and SBS researchers, who each interacted extensively with ERB’s evaluation processes. The participants came from all eight research universities of Israel, as well as seven large public and private academic colleges. Open, semi structured In-depth interviews were conducted in order to facilitate a critical reflective stance among the various participants, exploring their experiences, behaviors and the meanings they assign to ERB processes. Our research revealed two major themes. The first is the developmental trajectories in the construction processes of ERBs in Israel, comprised of the following stages: Initiation, expansion, opposition, and acceptance and assimilation. The second was a typology of participation throughout the ERBs’ construction process. Inspired by Merton’s strain theory, this typology includes conformists, ritualists, ideologists, control-freaks, and insurgents. The findings expose a unique perspective into the initiation, establishment, and development of ERBs, which can shed light on the role of ERBs in general, as well as point out how resistance to ERBs, as well as the different reasons for championing them, affected not only ERBs form and their legitimacy, but also their interaction with researchers.

Estimating welding deformation of ultra-thin mild steel bead-on-plate joints by means of inherent strain method

The inherent strain method as an efficient computational tool has been widely used to predict welding deformation for large and complex structures with thin and medium-thick plates. For ultra-thin plate welded structures, geometric non-linear phenomena often arise during welding because of the low stiffness. In this study, the welding deformation of 0.8 mm thick bead-on-plate mild steel joints was studied by both experimental method and thermal-elastic-plastic finite element method (T-E-P FEM), and the influences of weld lengths on Tendon force, transverse shrinkage and angular distortion were examined experimentally and numerically. Meanwhile, a non-linear elastic finite element method based on the inherent strain theory using ABAQUS software as a platform was developed to reproduce the welding deformation of the ultra-thin bead-on-plate joints with different weld lengths, and the adaptability of the inherent strain method to ultra-thin plate weldments was clarified.

A Comparison of Traditional Delinquency and Cyber-Delinquency: General Strain Theory and Community Protective Factors

ABSTRACT This study aims to analyze the COVID-19 pandemic’s impact on forms of delinquency among South Korean adolescents. We investigate the risks and protective factors associated with traditional delinquency and cyber-delinquency to provide guidance for prevention. We employed the theoretical frameworks of general strain theory (GST) and the Communities That Care (CTC) model to analyze panel data from middle school students in South Korea (N = 2,384) surveyed in 2019 and 2020 (during the COVID-19 pandemic). Traditional delinquency and cyber-delinquency in 2020 were dependent variables, and general strain and CTC variables in 2019 were independent variables. We conducted a logistic regression analysis and found that only academic pressure had a significantly positive relationship with traditional delinquency. Moreover, participation in extracurricular activities was a risk factor for traditional delinquency and cyber-delinquency. Contrary to expectations, the protective functions of CTC factors were not identified, likely due to the effects of the pandemic. We conclude this paper by discussing the implications of our findings and the limitations of our research.