Micro/nano-channel mechanical resonators have ultra-high resonance frequency, quality factor, and sensitivity in liquid environment. Hence they are usually used for high-precision detection and characterization in liquid environments. These resonators have broad application prospects in the fields of biology, medicine, and chemical industry. The detection and characterization functions of micro/nano-channel mechanical are highly dependent on their dynamic characteristics. Such devices are coupled systems composed of multiple components, including resonant structure, internal fluid, detected object, external excitation and so on. As a result, the involved dynamic problems are much complicated, and they have become a hotspot and bottleneck in the research of resonant devices. In this paper, the research progress of micro/ nano-channel mechanical resonators is reviewed. The dynamic design principles for high-precision detection and characterization are summarized. The dynamic characteristics, including stability, frequency response characteristics, energy dissipation, frequency fluctuations and so on, are discussed in detail. The physical mechanism of different dynamics and its influence on the performance of the resonator are expounded. It can provide theoretical reference and technical support for deep understanding of the dynamic design problem of micro/nano-channel mechanical resonators and improve the dynamic performance of the devices. And it is of great significance for the design, manufacture, and application of ultra-high frequency and ultra-high sensitivity devices.

Finite element (FE) analysis is extensively applied in practical engineering. However, FE model usually differs much from actual engineering structures due to modeling errors caused by meshing scales, boundary conditions, and material properties. Therefore an FE model has to be modified or updated by test data to make the FE model as close as possible to the real structure so that the updated model can be convincingly used for structural simulation, dynamic analysis, health monitoring or other engineering applications. Over the years, although FE model updating has been applied to many engineering applications successfully, the development of modern technology has put forward higher requirements on updated models, not only higher accuracy level but also higher confidence level. However, current methods are mostly confined to the linear structure hypothesis, which disagrees with the actual situations in many cases. Based on the background, this paper comprehensively reviews traditional FE model updating techniques with civil engineering structure as an example. Furthermore, influential model updating methods and their progress are surveyed and critically commented including recent progress of FE model validation. Especially, the evolution from linear to nonlinear FE model updating technology and essential research findings are summarized, then attractive perspectives are forecasted, and several promising issues are sketched out.

The process of fatigue failure beyond 107 cycles for a metallic material subjected to cyclic load is called very-high-cycle fatigue (VHCF). This review will summarize the research progress of VHCF starting with its origination in early 1980s, until the cutting-edge development in recent years. After Introduction, this review contains following parts: Origination of VHCF research, Main characteristics of VHCF, Characteristic region of crack initiation and related parameters for VHCF, Formation mechanisms and models for characteristic region of crack initiation, and Prediction models of VHCF properties. The relevant descriptions attempt to answer the following questions: What is VHCF? Why VHCF should be investigated? What are the essential scientific issues for VHCF? Why the tendency of S-N curve for VHCF is changed? Why crack initiates from the interior of material (specimen) for VHCF? What are the process and the mechanism of interior crack initiation? Some of the questions will be clearly answered, but some of them be just addressed by newly results, which require further exploration.

As one of the key components of a high-speed aircraft, the infrared window which is composed by matrix materials and functional films is widely applied. In the harsh environment, however, the infrared window works under complex aerothermal conditions, which may lead to its structural failure or dysfunction. Thus, the investigation on the aerothermal dynamic failure of infrared window in high-speed aircraft is of scientific importance and practical significance. This article reviews the studies on the aerodynamic thermal failure mechanisms of infrared windows in high-speed conditions, concerning typical materials, the aero-thermo-dynamics and structural failure or dysfunction. Finally, the prospects of further investigations on infrared windows are discussed.

Tumor microenvironment contains tumor cells, stromal cells and extracellular matrix, which plays an important role in tumor growth and development. The tumor microenvironment has its unique structural features. Physical forces in tumors can change the tumor microenvironment, disable the blood and lymphatic vessels, result in the abnormal metabolism, compress the interstitial structure, hinder the delivery of drugs, and induce stromal cells to change their behavior and promote tumor metastasis. So the forces in tumor have attracted increasing attention. In this review, we summarize the advances of mechanics problems in tumor and its microenvironments. We discuss the causes of solid stress, drug delivery and tumor metastasis. Also we introduce several strategies to restore the tumor microenvironments and their effects on tumor therapy.

Atomic force microscopy (AFM) based force spectroscopy is a high-sensitive mechanical detection method. With unprecedented accuracy, this method enables the characterization of a wide range of biological and synthetic bio-interfaces, ranging from tissues, cells, membranes, proteins, nucleic acids to functional materials. Besides the possibility of high resolution imaging of biological samples from the cellular level to the molecular level, AFM-based force spectroscopy allows their mechanical, chemical, conductive or electrostatic, and biological properties to be probed, and helps addressing fundamental challenges that cannot be addressed with other techniques. In this review, we summarize basic and advanced force spectroscopy approaches in micro biomechanics and evaluate their unique advantages and limitations.

The energy absorption system designed on the basis of nanofluidic behavior (also called nanofluidic energy absorption system, NEAS) will have a higher energy ab-sorption density than the conventional energy absorption materials, and can be repeatedly used. Thus it shows great advantages over the conventional energy absorption materials, especially for applications with a limited volume. In this paper, we reviewed the state-of-the-art of the energy absorption behavior of NEAS from both experimental investigations and numerical studies:the experimental work mainly includes quasi-static compression and dynamic compression tests; the computational simulations are mainly based on molecular dynamics simulations developed from the empirical potentials. Using quasi-static compres-sion, we can measure the load-displacement relationship of NEAS, determine the critical infiltration pressure, understand the loading-unloading-reloading behavior of NEAS (closely related to the repeated energy absorption performance of NEAS), and estimate the energy absorption density from the area below the load-displacement curve. By use of the dynamic compression tests, the NEAS performance of the protection against the impact load can be measured, which can be represented by decreasing the impact pulse magnitude and expand-ing the pulse width. The computational studies can clearly show the micro-level response of NEAS to the external load, based on which we can fully understand the energy absorption mechanism and the main controlling parameters of energy absorption density. The present study can help researchers understand the latest research progress of NEAS, and provide an important guideline for the design and optimization of NEAS.