A Practical Strain Sensor Based on Ecoflex/Overlapping Graphene/Ecoflex Sandwich Structures for Vocal Fold Vibration and Body Motion Monitoring

Graphene-based stretchable and flexible strain sensors are one of the promising “bridges” to the biomedical realm. However, enhancing graphene-based wearable strain sensors to meet the demand of high sensitivity, broad sensing range, and recoverable structure deformation simultaneously is still a great challenge. In this work, through structural design, we fabricated a simple Ecoflex/Overlapping Graphene/Ecoflex (EOGE) strain sensor by encapsulating a graphene sensing element on polymer Ecoflex substrates using a drop-casting method. The EOGE strain sensor can detect stretching with high sensitivity, a maximum gauge factor of 715 with a wide strain range up to 57%, and adequate reliability and stability over 1,000 cycles for stretching. Moreover, the EOGE strain sensor shows recoverable structure deformation, and the sensor has a steady response in the frequency disturbance test. The good property of the strain sensor is attributed to the resistance variation induced by the overlap and crack structure of graphene by structural design. The vibrations caused by sound and various body movements have been thoroughly detected, which exhibited that the EOGE strain sensor is a promising candidate for wearable biomedical electronic applications.

Monitoring Dynamic Deformation of Building Using Unmanned Aerial Vehicle

The height irregularity and complexity of steel structures bring difficulties to dynamic deformation monitoring. PDMS (photogrammetric dynamic monitoring system) can obtain the dynamic deformation of the steel structure, but the flexibility of monitoring is limited because the camera station can only be placed on the ground. In this study, UAV (unmanned aerial vehicle) -PDMS is innovatively proposed to be used in monitoring dynamic deformation of steel structures, and it is verified in the steel frame test and Jinan Olympic Sports Center Tennis Stadium test. To solve the problem that the attitude of UAV cannot be strictly maintained in the hovering process, the improved Z-MP (zero-centered motion parallax) method is used, and the monitoring results are compared with the original Z-MP method. The feasibility of UAV-PDMS applied to steel structure deformation monitoring and the feasibility of improving the Z-MP method to reduce UAV hovering error are verified. The monitoring results showed that the steel structures of the Jinan Olympic Sports Center Tennis Stadium were robust, and the deformations were elastic and within the permissible value.

Research on the Dynamic Response of Frame Structure under the Explosion Load of Acetylene-Air Mixture

Explosion is the act of generating huge energy in an instant and spreading rapidly around it. Due to the suddenness, fast propagation speed and high peak load of explosions, compared with other natural disasters, the damage it brings to humans is more significant and difficult to prevent. Among them, the explosion of acetylene-air mixture is the most typical explosion problem. This paper uses SAP2000 finite element software to perform a fine simulation of actual explosion events, studies the effect of the explosion of acetylene-air mixture on the frame structure column, and discusses the displacement and acceleration changes of various components. Research shows that the use of the principle of linear assumption of explosive load can effectively simulate the actual explosion situation. The structural damage and deformation caused by the explosive load have locality and weak transmission. When the peak of the explosion load is larger, the structure deformation is greater, and the impact of the explosion load on the structure is isotropic.

Deformations of surface defect moduli spaces

Given a 4d $$ \mathcal{N} $$ N = 2 superconformal theory with an $$ \mathcal{N} $$ N = (2, 2) superconformal surface defect, a marginal perturbation of the bulk theory induces a complex structure deformation of the defect moduli space. We describe a concrete way of computing this deformation using the bulk-defect OPE.

Operating Behavior of Sliding Planet Gear Bearings for Wind Turbine Gearbox Applications—Part II: Impact of Structure Deformation

The use of planetary gear stages intends to increase power density in drive trains of rotating machinery. Due to lightweight requirements on this type of machine elements, structures are comparably flexible while mechanical loads are high. This study investigates the impact of structure deformation on sliding planet gear bearings applied in the planetary stages of wind turbine gearboxes with helical gears. It focuses on three main objectives: (i) development of a procedure for the time-efficient thermo-elasto-hydrodynamic (TEHD) analysis of sliding planet gear bearing; (ii) understanding of the specific deformation characteristics of this application; (iii) investigation of the planet gear bearing’s modified operating behavior, caused by the deformation of the sliding surfaces. Generally, results indicate an improvement of predicted operating conditions by consideration of structure deformation in the bearing analysis for this application. Peak load in the bearing decreases because the loaded proportion of the sliding surface increases. Moreover, tendencies of single design measures, determined for rigid geometries, keep valid but exhibit significantly different magnitudes under consideration of structure deformation. Results show that consideration of structure flexibility is essential for sliding planet gear bearing analysis if quantitative assertions on load distributions, wear phenomena, and interaction of the bearing with other components are required.

Monitoring Data Analysis and Structural Reliability of Foundation Pit During Construction: A Case Study

In order to solve the problem that only considering the deformation of the side wall or the ground settlement of a single factor of the reliability evaluation may lead to insecurity, a deformation reliability evaluation method considering both the deformation of the side wall and the ground settlement is proposed. This evaluation method is used to evaluate the reliability of foundation pit structure deformation of Jinan metro in Shandong Province, China. Through the study of the deformation of the side wall and ground settlement loss on six profiles, the influence of the coefficient (λ、α and β) on the reliability is considered, and the recommended value of the coefficient (λ、α and β) is given. The reliability of six profiles is evaluated and the reliability level is obtained successfully. The reliability evaluation method can solve the problem that considering a single failure mode may lead to insecurity, and can provide an effective solution to the reliability evaluation of foundation pit retaining structure deformation.