High-precision impact calculation method and system for ship equipment

Abstract

The invention provides a high-precision impact calculation method and system for ship equipment, and the method comprises the steps: M1, obtaining an element impact characteristic F-S curve through the impact rigidity test of a vibration isolation impact-resistant element; M2, establishing an accurate ship equipment impact calculation model in finite element software according to the obtained element impact characteristic F-S curve; M3, applying a load to the ship equipment impact calculation model by utilizing an impact load; m4, after the load of the ship equipment impact calculation model is applied, response evaluation is conducted on the ship equipment. According to the method, the performance parameters of the vibration isolation element are more accurate, the parameters of the vibration isolator are not linear or constant any more, and the characteristic parameters of the rubber element under the high strain rate are obtained through the impact test.

Description

technical field [0001] The present invention relates to the research field of anti-shock design of ship equipment, in particular, to a high-precision impact calculation method and system for ship equipment, and more specifically, to a high-precision impact calculation method for ship equipment installed with elastic vibration isolation. Background technique [0002] In the newly released shock resistance requirements for equipment, compared with the GJB1060.1 "Environmental Condition Requirements for Ships-Mechanical Environment", the shock energy is increased by more than 85%, and the duration of shock load is doubled. More stringent requirements are put forward for the impact resistance and impact protection design, and the accuracy of the impact calculation method needs to be improved to meet the higher standard work requirements. At present, the calculation accuracy of the shock response of ship equipment is not high, the main reasons are: [0003] At present, the calcu...

AI Technical Summary

Problems solved by technology

However, since the impact stiffness of the components needs to be obtained by the impact test bench, the construction of the bench, data acquisition, post-processing methods, etc. are difficult, so in the current calculation, the impact stiffness of the components is mostly used as a fixed value, (generally the dynamic stiffness 1.5 to 2.5 times of that); at the same time, when most commercial software is inputting stiffness, its interfaces are mostly fixed values, and it is difficult to input F-S curves

The real value of the impact stiffness is difficult to obtain, and the input method of the stiffness is limited, resulting in a large error in the calculation of the impact response

[0005] 2) The connection mode of the impact element, the base, and the intermediate mass is quite different from the actual one

However, the point-to-point connection makes the transmission of impact energy quite different from the actual surface transmission, and causes stress concentration on the base and intermediate mass, which brings distorted information to structural designers.

[0006] 3) Non-linear factors such as stoppers are not fully considered

A limit gap is set inside the limit element. Within the limit gap, the limit element does not work, but after the impact displacement of the device and equipment exceeds the limit gap, the limit element starts to work, resulting in a large stiffness, which is about ordinary 10-100 times that of the vibration isolation element, resulting in strong nonlinearity and secondary impact on the equipment. The impact energy is large and can seriously damage the equipment

Most of the current commercial software cannot simulate this strong nonlinearity, resulting in large errors in calculation results

[0007] 4) The impact load input method is quite different from the actual one

However, after introducing a large mass, the mass matrix of the discrete equation in the calculation process is artificially increased. At the same time, due to the impact of the large mass, the components in the vibration isolation and anti-shock device have large errors in their impact deformation, resulting in low calculation accuracy.

The acceleration field law equates the impact load to a "gravity field", so that the entire equipment and devices are subject to the impact load. The calculation results of this method are easy to converge, but due to the change of boundary conditions, the calculation error is large

[0008] 5) It is difficult to determine the evaluation parameters of the shock resistance performance of ship equipment

However, the acceleration calculated by the impact is mostly a time-domain curve, and there is currently no unified method to equate the acceleration value of the time-domain curve to the fixed value of the "static G method".

In some literatures, the maximum value of the acceleration in the time-domain curve is equivalent to the fixed value of the "static G method", but because the fixed value of the "static G method" is represented as the acceleration value corresponding to the low-order mode, the error larger

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