Wave Mode Control of Cantilever Slab Structure of T-Beam Bridge with Large Aspect Ratio

The cantilever plate structure in a T-beam bridge with a large aspect ratio will cause vibration under the influence of environmental disturbance and self-stress, resulting in fatigue damage of the plate structure. Wave control based on elastic wave theory is an effective method to suppress the vibration of the cantilever plate structure in a beam bridge. Based on the classical thin plate theory and the wave control method, the active vibration control of the T-shaped cantilever plate with a large aspect ratio in the beam bridge is studied in this paper. The wave mode control strategy of structural vibration is analyzed and studied, the controller is designed, the vibration mode function of the cantilever plate is established, and the control force/sensor feedback wave control is implemented for the structure. The dynamic response of the cantilever plate before and after applying wave control force is analyzed through numerical examples. The results show that the response of the structure is intense before control, but after wave control, the structure increases damping, absorbs the energy carried by the elastic wave in the structure, weakens the sharp response, and changes the natural frequency of the structure to a certain extent.

Menentukan Desain Struktur Atas Gedung Fajar Biru Trenggalek Berdasarkan SNI (Standart Nasional Indonesia)

A multi-storey reinforced concrete building is very prone to collapse. Therefore, proper structural planning is needed in order to qualify the strength and security of the structure. Fajar Biru Building is a building that will be built in Karangsuko village of Trenggalek Regency, East Java. The building functioned as a cost with a building area of 340 m2, and has a total of 4 floors. The method used is the SRPMM (Medium Moment Musician Frame System) method which refers to SNI 1726:2012, and SNI 2847:2013. Planning includes the calculation of beams, floor plates, and columns. From the results of the calculations that have been done. on the floor plate structure with a plate thickness of 120 mm, Ø12 tree bones are used with a distance of 100 mm for pedestals and 150 mm for field areas. On the looping of B1 beams with dimensions of 300x350 mm used 6-D16 tree bones for focus and 4-D16 for field areas with Ø10-70 mm for focus and Ø10-140 mm for field areas. For the repeating of Column K1 with dimensions of 300x600 mm used 10-D16 principal bones with a Ø10-70 mm dimension. So that from these results can be used as a reference in the implementation of the construction of the blue dawn building.

Experimental Study of a Piezoelectric De-Icing System Implemented to Rotorcraft Blades

A four-year project investigating the use of piezoelectric actuators as a vibration-based low power de-icing system has been initiated at the Anti-Icing Materials Laboratory. The work done preceding this investigation consisted of studying, numerically and experimentally, the system integration to a flat plate structure, the optimal excitation of the system, the resonant structural modes and the shear stress amplitudes to achieve de-icing for that structure. In this new investigation, the concepts and conclusions obtained on the flat plate structure were used to design and integrate the system into a rotating blade structure. An experimental setup was built for de-icing tests in rotation within an icing wind tunnel, and a finite-element numerical model adapted to the new geometry of the blade was developed based on the expertise accumulated using previous flat plate structure analysis. Complete de-icing of the structure was obtained in the wind tunnel using the developed de-icing system, and its power consumption was estimated. The power consumption was observed to be lower than the currently used electrothermal systems. The finite-elements numerical model was therefore used to study the case of a full-scale tail rotor blade and showed that the power reduction of the system could be significantly higher for a longer blade, confirming, therefore, the relevance of further de-icing investigations on a full-scale tail rotor.

Folding responses of origami-inspired structures connected by groove compliant joints

Folding responses of a set of notch-type compliant joint candidates are first numerically explored before the victorious one is implemented in actuating the deployment of Miura origami-inspired plate structure. The considered notch-type compliant joints are groove, elliptical holes, rectangular holes, and outside LET types. The exploration and examination of the kinematic and dynamic characteristics of these joints include performance indicators such as stress contour, load-deformation, moment-angle, and stiffness-angle relationships for different geometric parameters, with a specific interest in their hysteretic behaviors. Considering various performance features, the groove joints have been identified as the most suitable to be employed as the Miura origami-inspired hinge. The Miura origami-inspired plate folding behaviors are further explored considering various numbers and placements of groove joints. It has been found that the Miura plate performs better with the groove joint compared to that without one and that the single and double groove joint modes are inter-correlated. The study offers a comprehensive understanding of the effects of geometrical variation of numerous compliant joints on the folding behaviors as well as the further implementation of the victorious one in actuating the deployment of the Miura origami-inspired plate structure in accordance with the number and location of the joint.