Experimental investigation of high temperature thermal-vibration characteristics for composite wing structure of hypersonic flight vehicles

A thermal-vibration test system is established by combining the high-temperature transient heating simulation system and vibration test apparatus, and this system can carry out experimental research on the thermal modal of high-temperature-resistant composite wing structure of hypersonic flight vehicles under high temperature environment with 1100°C. The vibration signals of the composite wing structure in high-temperature environments are transmitted to non-high temperature field by using self-developed extension configurations and then the vibration signals are measured and identified by using ordinary acceleration sensors. Based on a time-frequency joint analysis technique, the experimental data is analyzed and processed to obtain the key vibration characteristic parameters of composite wing structure, such as the natural frequency and mode shapes, in a thermal-vibration coupled environment up to 1100°C. The experimental results provide an important basis for the dynamic performance analysis and safety design of composite wing structure under high-temperature thermal-vibration conditions

Experimental investigation of high temperature thermal-vibration characteristics for composite wing structure of hypersonic flight vehicles

A thermal-vibration test system is established by combining the high-temperature transient heating simulation system and vibration test apparatus, and this system can carry out experimental research on the thermal modal of high-temperature-resistant composite wing structure of hypersonic flight vehicles under high temperature environment with 1100°C. The vibration signals of the composite wing structure in high-temperature environments are transmitted to non-high temperature field by using self-developed extension configurations and then the vibration signals are measured and identified by using ordinary acceleration sensors. Based on a time-frequency joint analysis technique, the experimental data is analyzed and processed to obtain the key vibration characteristic parameters of composite wing structure, such as the natural frequency and mode shapes, in a thermal-vibration coupled environment up to 1100°C. The experimental results provide an important basis for the dynamic performance analysis and safety design of composite wing structure under high-temperature thermal-vibration conditions

Two new practical models for estimating reliability-based fatigue strength of composites

This paper outlines two new practical models to evaluate fatigue residual strength and the overall range of life for reliability-based design. A new fatigue-driven residual strength surface model with four parameters is derived based on an expression form of power function product to estimate the parameters more easily and expediently, and logically characterize the physical characteristics and the phenomenological quantitative laws. A more appropriate S-N curve formulation with four parameters is presented to cover overall life range. By means of the likelihood principle and the linear regression, the parameter determination formulae of these two models are respectively established to deal with the test data effectively and easily. The probability distributions for these two models are also given. Finally, the models are applied to two sets of experimental data, demonstrating the practical and effective use of the proposed models. It is shown from these examples that fatigue-driven residual strength and the overall range of life can be obtained realistically according to the small sample test data using the new formulae

MiR-146a Aggravates LPS-Induced Inflammatory Injury by Targeting CXCR4 in the Articular Chondrocytes

Background/Aims: Osteoarthritis (OA) as a degenerative disease is a major problem in ageing populations. To better understand the molecular mechanisms in the pathogenesis of OA, this study explored the role of microRNA (miR)-146a in the articular chondrocytes. Methods: The articular chondrocyte line ATDC5 was used to simulate inflammatory injury by LPS administration in vitro. Cell viability, apoptosis, mRNA expressions and productions of inflammatory factors were assessed, respectively. Mir-146a and Cxcr4 mRNA expressions were measured by qRT-PCR. Targeting effect of miR-146a on Cxcr4 3’UTR was assessed by luciferase activity analysis. Protein expression levels of CXCR4 and main factors in PI3K/AKT, Wnt/β-catenin signal pathways were measured by western blotting. Results: LPS exposure suppressed cell viability, prompted apoptosis of ATDC5 cells, and stimulated expression and release of inflammatory factors. MiR-146a was upregulated in LPS-induced cells. Overexpression of miR-146a further aggravated LPS-induced inflammatory injury, while it was reduced after miR-146a was knocked down. CXCR4 expression was negatively regulated by miR-146a. CXCR4 was a direct target of miR-146a and thus involved in regulatory effect of miR-146a on the injured chondrocytes, which was also related with phosphorylation levels of PI3K/AKT and expressions of Wnt/β-catenin signal factors. Conclusion: miR-146a promoted inflammatory response of articular chondrocytes via targeting CXCR4 and suppressing CXCR4 expression. Overexpression of CXCR4 could attenuate the inflammatory injury. Our findings provided novel evidence which might be useful for further studies exploring therapeutic approaches for OA via targeting miR-146a

AAV induces hepatic necroptosis and carcinoma in diabetic and obese mice dependent on Pebp1 pathway

Abstract Obesity and diabetes are risk factors for hepatocellular carcinoma (HCC); however, the underlying mechanisms are yet to be elucidated. Adeno‐associated virus (AAV) frequently infects humans and has been widely used in gene therapy, but the risk of AAV infection such as HCC should be further evaluated. Here, we show that recombinant AAV injection caused liver injury, hepatic necroptosis, and HCC in db/db or high‐fat diet‐induced hyperglycemic and obese mice, but not in mice with only hyperglycemia or obesity. Prednisone administration or knockdown of Pebp1, highly expressed in db/db mice, alleviated hepatic injury and necroptosis induced by recombinant AAV in mice with diabetes and obesity. Inhibition of Pebp1 pathway also attenuated inflammation and necroptosis in vitro. Our findings show that AAV infection is a critical risk factor for HCC in patients with diabetes and obesity, and AAV gene therapy for these patients should be carefully evaluated. Both prednisone treatment and targeting Pebp1 pathway are promising strategies to alleviate inflammation and necroptosis that occurred in AAV gene therapy or related diseases