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While suction cups prevail as common gripping tools for a wide range of real-world parts and surfaces, they often fail to seal the contact interface when engaging with irregular shapes and textured surfaces. In this work, the authors propose a suction-based soft robotic gripper where suction is created inside a self-sealing, highly conformable and thin flat elastic membrane contacting a given part surface. Such soft gripper can self-adapt the size of its effective suction area with respect to the applied load. The elastomeric membrane covering edge of the soft gripper can develop an air-tight self-sealing with parts even smaller than the gripper diameter. Such gripper shows 4 times higher adhesion than the one without the membrane on various textured surfaces. The two major advantages, underactuated self-adaptability and enhanced suction performance, allow the membrane-based suction mechanism to grip various three-dimensional (3D) geometries and delicate parts, such as egg, lime, apple, and even hydrogels without noticeable damage, which can have not been gripped with the previous adhesive microstructures-based and active suction-based soft grippers. The structural and material simplicity of the proposed soft gripper design can have a broad use in diverse fields, such as digital manufacturing, robotic manipulation, transfer printing, and medical gripping., Advanced Science, 8 (17), ISSN:2198-3844

In this study, a novel crash box idea was presented, including a step-by-step collapsible structure by joining coaxial tubes with gradual bonding surface areas. This telescopic crash box absorbed impact energy by sequentially fracturing the adhesive interfaces from the top tube to the back tubes. In each bonding interface fracture, a certain amount of the impact energy was reduced. These gradually broken adhesive bonds and subsequent movement of the coaxial tubes were increased pedestrian safety by producing fewer impact forces and adding more braking time. Due to the just adhesive joints break after small hits, a broken crash box can be repaired easily by bonding coaxial tubes. Validation of the design was performed using the Finite Element Simulations by parametric modelling of the representative design of crash boxes with frontal impact simulations of a vehicle. Transmitted forces to the vehicle body were obtained according to impact duration. Impact energies were obtained by calculating the area under impact of force–displacement curves. The optimal size of the coaxial tube bonding interfaces and the number of the telescopic tubes were obtained for maximum energy absorption comparing with conventional crash boxes.

Adhesive bonded joints have attracted the attention of many industries, such as marine and aerospace, as an interesting alternative to the traditional joining methods as riveting, bolting or welding. One of the most important damage modes of adhesive joints and interfaces is related to the non-linear and irreversible debonding process, which includes the formation and propagation of interface cracks, up to the complete detachment of the adherends. In this framework, the interfacial debonding problem is here handled through an innovative cohesive formulation, named as Enhanced Beam Theory (EBT), where the specimens are considered as an assemblage of two composite sublaminates, partly bonded together by an elastic interface. This last one is modeled with a continuous distribution of cohesive springs acting in the normal and/or tangential direction, depending on the mixed-mode condition. This generalizes the idea suggested recently in [1] for a single mode-I debonding, and extended in [2] to include mixed loading, geometry and mechanical conditions. The debonding onset and propagation is determined numerically along the weak interfaces subjected to mixed-mode conditions. The accuracy of the proposed formulation is verified against some analytical predictions and theoretical formulations available in literature [3], [4].

В настоящем исследовании разработаны и апробированы новые методы визуализации и ранней неинвазивной in vivo диагностики состояния адгезивных соединений твёрдых тканей зуба и полимерного материала с применением физических методов – видеодиагностики и низкокогерентной оптической компьютерной томографии. В соответствии с рекомендациями международной ассоциации стоматологов и c использованием разработанных авторами статьи аналогов USPHS критериев, пригодных для физических методов диагностики, проведен качественный и количественный анализ состояния адгезивных интерфейсов реставраций указанными методами в сравнении со стандартными клиническими. Выявлено, что результаты исследований методом видеодиагностики находятся в полном соответствии с результатами клинических наблюдений, что делает возможным его применение как скринингового при профилактических клинических осмотрах населения. Метод низкокогерентной оптической компьютерной томографии позволяет in vivo, in situ, неинвазивно мониторировать состояние адгезивных соединений твёрдых тканей зуба и композиционных полимерных материалов, а также выявлять скрытые кариозные полости и дефекты реставраций. Показано, что метод низкокогерентной оптической компьютерной томографии отличается наибольшей информативностью и достоверностью по сравнению со стандартными клиническими методами диагностики и методами видеодиагностики при определении состояния адгезивных соединений., In the present paper new methods of visualization and early stage non-invasive in vivo diagnostics of the state of adhesive interfaces between hard tooth tissues and polymer material have been developed and tested by using two physical methods, namely, video diagnostics and optical low-coherence computer tomography. In accordance with the recommendations of the International Association of Dentists (FDI) and by using the analogues of USPHS criteria developed by the authors, which are suitable for the application of physical methods of diagnostics, the qualitative and quantitative analyses of the state of adhesive interfaces of restorations were carried out by using mentioned methods in comparison with standard clinical ones. It has been revealed that the results of video-diagnostics tests are in full agreement with the results of clinical observations, which makes it possible to use this method as a screening one for preventive clinical examinations. The method of optical low-coherence computer tomography allows to non-invasive monitoring in vivo and in situ the state of adhesive interfaces between hard tooth tissues and composite polymer material, as well as revealing of hidden carious cavities and defects of restorations. It has been shown that the method of optical low-coherence computer tomography is more informative and reliable in comparison with standard clinical diagnostics methods and with the methods of video-diagnostics, when determining the state of adhesive interfaces.

The present research deals with the delamination process in multi-layered composite specimens, with a reduced computational effort. The adhesive interface between sublaminates is represented as a continuous distribution of elastic-brittle springs in the normal and/or tangential direction depending on the interfacial mixed-mode condition. Each composite adherend, instead, is modelled according to the Timoshenko’s beam theory. The proposed formulation is here enhanced through the Generalized Differential Quadrature (GDQ) method, where the differential equations of the problem are solved directly in a strong form. Thus, the possibility of tracking the delamination response of the specimens is provided locally in a numerical sense, in terms of interface stresses, internal forces and displacements but also in terms of critical fracture energies and mode mixity angles. A further check of the proposed formulation is performed with respect to some standard solutions available in literature. The good agreement between numerical and theoretical predictions verifies the efficiency of the proposed GDQ approach for the study of complex mixed-mode delamination phenomena in composite materials and joints.