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Simple expressions for upper and lower limits to the shear modulus of honeycomb sandwich cores are obtained by application of the Unit Displacement and Unit Load methods in conjunction with simplifying assumptions as to the strain and stress systems respectively in the core. The theory is given for cores built up from foil ribbons to form cells of general honeycomb form. Test methods for the experimental determination of the shear modulus are also discussed. Of these, the three‐point bending test on sandwich beams is considered most satisfactory and results of such tests on steel and aluminium foil honeycombs show good agreement with the theory.

AT Schiphol Airport the first Dutch airliner to be built since the war is nearing completion. The Royal Netherlands Aircraft Company Fokker, which was responsible for a large number of successful airliner designs in the period between the wars, has designed this latest aircraft as a medium size ‘Dakota replacement’. Called the Fokker F.27 Friendship, it carries 28–36 passengers and a liberal amount of luggage on stage lengths up to 1,000 miles. It is powered by two Rolls‐Royce Dart propeller turbine engines installed in the high‐aspect‐ratio high wing. The advanced design incorporates a number of interesting structural features which contribute to efficient production and economy of operation.

The computational drawbacks of existing numerical methods have forced researchers to rely on heuristic algorithms. Heuristic methods are powerful in obtaining the solution of optimization problems. Although they are approximate methods (i.e. their solution are good, but not provably optimal), they do not require the derivatives of the objective function and constraints. Also, they use probabilistic transition rules instead of deterministic rules. The purpose of this paper is to present an improved ant colony optimization (IACO) for constrained engineering design problems.

IACO has the capacity to handle continuous and discrete problems by using sub‐optimization mechanism (SOM). SOM is based on the principles of finite element method working as a search‐space updating technique. Also, SOM can reduce the size of pheromone matrices, decision vectors and the number of evaluations. Though IACO decreases pheromone updating operations as well as optimization time, the probability of finding an optimum solution is not reduced.

Utilizing SOM in the ACO algorithm causes a decrease in the size of the pheromone vectors, size of the decision vector, size of the search space, the number of function evaluations, and finally the required optimization time. SOM performs as a search‐space‐updating rule, and it can exchange discrete‐continuous search domain to each other.

The suitability of using ACO for constrained engineering design problems is presented, and applied to optimal design of different engineering problems.

BECAUSE of the apparently low moduli obtained from it, the double block shear test has recently been the subject of some criticism. The purpose of this paper is to re‐examine the double block shear test as a means of measuring the shear stiffness of foil honeycomb cores because of the advantages in simplicity it has over other methods. The two most widely used methods of testing are shown in FIG. 1, they are fundamentally different and illustrate the two approaches to honeycomb foil testing.

The purpose of this paper is to identify and prioritize the causes of delay in development projects and present strategies to reduce the delay.

The discussion includes the failure mode and effects analysis (FMEA) method for converting survey data, fuzzy risk priority number (FRPN) for prioritizing the delay factors, and the proposed solutions to reduce the delay of projects.

The research provided prioritized delay factors to show the importance of each delay factor in the projects by analyzing the survey data. Results show that lack of proper contract price to win the tender has the most impact on the delay of development project between delay factors.

This study offered some guidelines for people who are involved with contracts and development projects, so that they can use these suggestions to prevent possible factors that may cause delay in projects. This paper also demonstrated a process of analyzing the data which was provided by FMEA and FRPN methods.

The purpose of this paper is to propose variants of an adaptive penalty scheme for steady-state genetic algorithms applied to constrained engineering optimization problems.

For each constraint a penalty parameter is adaptively computed along the evolution according to information extracted from the current population such as the existence of feasible individuals and the level of violation of each constraint. The adaptive penalty method (APM), as originally proposed, computes the constraint violations of the initial population, and updates the penalty coefficient of each constraint after a given number of new individuals are inserted in the population. A second variant, called sporadic APM with constraint violation accumulation, works by accumulating the constraint violations during a given insertion of new offspring into the population, updating the penalty coefficients, and fixing the penalty coefficients for the next generations. The APM with monotonic penalty coefficients is the third variation, where the penalty coefficients are calculated as in the original method, but no penalty coefficient is allowed to have its value reduced along the evolutionary process. Finally, the penalty coefficients are defined by using a weighted average between the current value of a coefficient and the new value predicted by the method. This variant is called the APM with damping.

The paper checks new variants of an APM for evolutionary algorithms; variants of an APM, for a steady-state genetic algorithm based on an APM for a generational genetic algorithm, largely used in the literature previously proposed by two co-authors of this manuscript; good performance of the proposed APM in comparison with other techniques found in the literature; innovative and general strategies to handle constraints in the field of evolutionary computation.

The proposed algorithm has no limitations and can be applied in a large number of evolutionary algorithms used to solve constrained optimization problems.

The proposed algorithm can be used to solve real world problems in engineering as can be viewed in the references, presented in this manuscript, that use the original (APM) strategy. The performance of these variants is examined using benchmark problems of mechanical and structural engineering frequently discussed in the literature.

It is the first extended analysis of the variants of the APM submitted for possible publication in the literature, applied to real world engineering optimization problems.

The incipient growth of the fused deposition modeling (FDM) techniques encourages the development of models to predict the behavior of these parts involving complicated and heterogeneous geometries whose behavior strongly diverges from the continuous model hypothesis. This paper aims to address the problem of predicting the flexural properties of FDM parts building on the geometrical similarity between a typical FDM part and a sandwich panel.

This paper takes advantage of the morphological similarity between FDM structures and composite sandwich panels. Thus, an approach based on classic sandwich theory is developed to validate its goodness to predict the flexural behavior of FDM parts. A set of tensile and flexural tests for FDM parts were conducted varying the density of the core pattern (10%, 15%, 20% and 25%), being the proposed model and the predicted results validated.

The results showed a good accordance between the predicted values of stiffness and the experimental data. Although this is especially evidenced for low infill density values, for densities above 20% the experimental values noticeably exceed the maximum predicted stiffness, which can be explained by the non-compliance of the foil honeycomb hypothesis for high-density patterns. The main implication of these findings lies in the possibility of using advanced models from thin-foil structures as a base to develop accurate analytical approaches to model FDM structures.

Although the experimental characterization of FDM parts has been a matter of study in the literature, the development of robust theoretical models that consider the influence of the particular morphology of these parts is still a challenge in this field. The approach proposed in this study constitutes the first step to develop a complete analytical model to predict the complex behavior of FDM printed parts.

Past research on the motivational processes underpinning knowledge sharing has assumed that the sharing processes are similar for all individuals. Yet, sharing is a fundamental affiliative behavior, and the sharing processes can differ between people. This study aims to propose and test a model of the moderating influence that employee attachment patterns have on the theory of reasoned action (TRA)-defined knowledge sharing processes.

The authors administered a questionnaire to 1,103 employees from a range of industries who participated in an online Qualtrics survey. Advanced forms for structural equation modeling and latent profile analysis were used to assess the proposed model.

The results revealed that participants in the study exhibited the latent profiles corresponding to secure, dismissive, preoccupied and fearful patterns. The preoccupied cohort had the lowest knowledge sharing behavior, yet the strongest links within the sharing process. Secure, dismissive and fearful had similar sharing levels, but the strength of the TRA-defined processes differed. These findings underscore equifinality: although sharing may be approximately equal across different attachment patterns, the fundamental processes underpinning sharing differ.

The authors used self-report data, given that sharing attitudes, norms and intentions may not be overly amenable to ratings even from well-acquainted others. Further, the use of advanced analytical methods helps to minimize common method concerns. Additionally, causal mechanisms underscoring the TRA have been demonstrated (Ajzen and Fishbein, 2005), allowing us to explore the moderating role of attachment patterns.

This study speaks to the importance of considering employees’ attachment patterns, and developing comprehensive intra-organizational norms, policies and systems that support and encourage knowledge sharing from employees with a variety of attachment patterns.

This study uniquely contributes to knowledge sharing literatures by incorporating attachment patterns as moderators within the TRA-defined sharing processes. The authors provide important insights on the role of individuals’ attachment patterns have for knowledge sharing behaviors, but also highlight how structure of knowledge sharing differed across subgroups of employees, determined based on their dispositional attachment pattern.

The authors tested whether the effect of alcohol consumption during work hours on workplace aggression was influenced by the combined impact of individuals' job insecurity and love of the job.

The authors employed a time-lagged design whereby 325 working adults (166 men; 159 women) provided data at two time points. Respondents were asked to report their typical alcohol consumption volume in a workday, the extent to which they loved their job, and how insecure they felt about their job. Approximately one week later, respondents completed a workplace aggression measure.

A substantial positive relationship was observed between the volume of alcohol consumed during work hours and the likelihood of aggressive acts. Beyond this preliminary finding, the authors found evidence for a three-way interaction. It appears that the fear of losing a beloved job creates a condition under which the drinking-aggression relationship is particularly strong.

Besides formal rules deterring alcohol consumption during work hours, managers may look to implement measures that nurture a sense of job love and job security, which can be beneficial in preventing aggression resulting from drinking in the workplace.

By examining alcohol consumption during a typical workday, the study captures the contextual and proximal effects of drinking, which are often not observed in workplace-focused studies that operationalize alcohol consumption in general terms. The findings also suggest that if employees who drink during work hours are afraid of losing the job they love, a particularly stressful situation is created in which workplace aggression is more likely to happen.

The term catastrophizing was coined by Ellis (1962) and commented on by Beck (1979). Since that time, much research has been done on the topic and a recent review article postulated that catastrophizing served as a transdiagnostic mechanism across the psychiatric disorders (Gellatly and Beck, 2016). In rational emotive behavior therapy (REBT), there is a greater emphasis placed on the underlying irrational beliefs than the surface-level automatic thoughts; therefore, REBT therapists tend to focus on Awfulizing as opposed to catastrophizing. While these terms sound similar, it is unclear what theoretical overlap and distinction exists between the concepts. The paper aims to discuss these issues.

This paper is a review and synthesis of the extant literature, drawing from both theorists and empirical studies, to map out the similar and unique aspects of each cognition.

Awfulizing and catastrophizing are distinct concepts with differing effects on cognitive, affective and behavioral responses; these findings extend beyond theoretical models and are supported by empirical literature.

This review has direct implications for practitioners of the cognitive and behavioral therapies, including REBT, and those seeking an integration of the cognitive therapies.