汽车电子功能安全标准ISO26262解析（四）——FMEDA

Evaluation of the hardware architectural metrics.

FMEDA是硬件架构度量的一种验证方法。

The objective of this clause is to evaluate the hardware architecture of the item against the requirements for fault handling as represented by the hardware architectural metrics.

FMEDA的目的是通过硬件架构度量参数来验证硬件架构中为了满足需求而采用的错误处理机制。

This clause describes two hardware architectural metrics for the evaluation of the effectiveness of the architecture of the item to cope with random hardware failures.

为了处理硬件随机失效，采用两种硬件架构度量参数来验证架构的有效性。

=> FMEDA是针对硬件随机失效的分析方法。

For electromechanical hardware parts, only the electrical failure modes and the failure rates are considered.

对于电子-机械硬件元器件，只考虑电子方面的失效模式和失效率。

The estimated failure rates for hardware parts used in the analyses shall be determined:

硬件元器件的失效率可以通过以下几种方法决定：

(1) using hardware part failure rates data from a recognised industry source.

使用公认的工业数据库中的硬件元器件失效率，例如 SN29500。

(2)  using statistic hased on field returns or tests. In this case, the estimated failure rate should have an adequate confidence level.

使用静态的市场返回品失效率或测试失效率。这种情况下，要求估计的失效率要有足够的置信度。

(3) using expert judgement founded on an engineering approach based on quantitative and qualitative arguments. Expert judgement shall be exercised in accordance with structured criteria as a basis for this judgement. These criteria shall be set before the
estimation of failure rates is made.

通过专家判断，专家判断是基于定性和定量讨论的一种工程方法。专家判断在实施的过程中应该以结构性的标准作为基础。这些结构性的标准应该在失效率评估之前建立完成。

The criteria for expert judgement can include field experience, testing, reliability analysis and novelty of design.

专家判断的标准包括市场经验、测试、可靠性分析和设计的新颖性。

为了达到ASIL等级的需求，每个安全目标分析结果应满足表4和表5的要求。