Background

This paper deals with the possible field of application of ultrasonic Surface Reflection Method (SRM) to achieve the mechanical characteristics of isotropic materials. This method is based on the measurement of the amplitude of the reflected wave at the interface between reference material and the material to be characterised. Objective: The purpose of Part 1 of this paper is to establish the theoretical conditions for the applicability of SRM.

Methods

First, the theoretical formulas necessary to obtain the mechanical properties of the material to be tested will be established. Then, on the basis of these analytical formulas, the validity of the results for the material to be studied will be discussed according to the choice of the mechanical properties of the reference material through uncertainty calculations. The measurand error of SRM is then compared to that of traditional methods (transmission, transmission in water bath, pulse-echo).

Results

The analytical solution to the inverse problem (the mechanical characteristics of the tested medium based on those of the reference medium and the waves’ amplitude) will be given. From this analytical solution, an analysis of the measurand error will be performed and a method for choosing the reference material will be proposed.

Conclusions

It appears that SRM is better suited than traditional methods in two specific cases: measurement of small deviations of mechanical properties from a reference material or characterisation of high damping materials. In Part 2 of this paper, the practical conditions of applicability of the method are described and then applied to different kinds of materials.

中文翻译：

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超声表面反射法对各向同性材料的机械表征的潜在范围。第1部分：理论分析

背景

本文探讨了超声表面反射法（SRM）应用于各向同性材料力学特性的可能应用领域。该方法基于在参考材料和要表征的材料之间的界面处反射波的幅度的测量。目的：本文第1部分的目的是为SRM的适用性建立理论条件。

方法

首先，将建立获得被测材料的机械性能所必需的理论公式。然后，在这些解析公式的基础上，将通过不确定性计算，根据参考材料的机械性能选择，来讨论待研究材料的结果的有效性。然后将SRM的测量误差与传统方法（传输，在水浴中传输，脉冲回波）进行比较。

结果

将给出反问题的解析解（基于参考介质的机械特性和波幅来确定被测介质的机械特性）。从该分析解决方案中，将对被测量误差进行分析，并提出选择参考材料的方法。

结论

在两种特定情况下，SRM似乎比传统方法更适合：测量参考材料的机械性能的微小偏差或表征高阻尼材料。在本文的第2部分中，描述了该方法适用的实际条件，然后将其应用于不同种类的材料。