# Failure Mechanism of Multilayer Ceramic Capacitors under Transient High Impact
## 4 Conclusions  
In this paper, the transient change (and its mechanism) of the electronical parameters of multilayer ceramic capacitors during high-\(g\) impacts was analyzed via Machete hammer experiments. Further, by establishing a mechanical model and equivalent circuit model, the capacity and leakage current changes were studied, and a numerical simulation was carried out to verify the experimental results. To sum up, the experimental and simulation results indicate the following issues:  
1. Under high-\(g\) impact acceleration, in the MLCC occurs the phenomenon of parameter drift, in which the capacitance value becomes larger and the leakage current increases. Besides, the larger the rated capacitance and withstand voltage of the MLCC, the greater the capacitance change and leakage current drift. With impact acceleration of no more than 9000 g, the influence on the capacity and leakage current are reversible.
2. The facing area deformation is the dominant factor in the transient change of the capacity value. A mechanical model based on the facing area is established to calculate the capacity change. The numerical calculation results are consistent with the experimental results, and the relationship between the impact and capacity changes can be described semi-quantitatively.
3. The piezoresistive effect of the ceramic dielectric is the dominant factor in leakage current variation. The insulation resistance begins to decrease when the threshold pressure exceeds 2.7 MPa. With increasing pressure, the insulation impedance of the ceramic dielectric decreases continuously, and when the pressure reaches 18.1 MPa, the resistance drops gradually. By combining the P-R model and the equivalent circuit model, the relationship between the leakage current and impact acceleration can be simulated, which is an approximately exponentially increasing relationship.
4. The sudden increase in the leakage current of the ceramic capacitor causes the energy storage loss of the MLCC, which makes the detonator energy of the fuze insufficient. The design of the fuze's energy-storage capacitor must consider the leakage current during the impact and increase the design margin to ensure the reliability of the fuze.  
By analyzing the relationship between the different impact accelerations and parameter drift, and by calculating the failure threshold of the different specification parameters of the MLCC according to the mechanical model and equivalent circuit model, effectively provides guidance for the design of a penetration fuze's MLCC, to ensure the reliability of the fuze.  
[PERSON] and [PERSON] conceived and designed the experiments; [PERSON], [PERSON] and [PERSON] performed the experiments; [PERSON] and [PERSON] analyzed the data; [PERSON] and [PERSON] contributed analysis tools; [PERSON] wrote the paper. All authors have read and agreed to the published version of the manuscript.  
This research was funded in part by Key Basic Research Projects of Basic Strengthening Plan of China (Grant number 2017-JCJQ-ZD-004), in part by National Natural Science Foundation of China (Grant number 52007084), in part by the Natural Science Foundation of Jiangsu Province under Grant (BK20190470), and in part by the Central University Special Funding for Basic Scientific Research (Grant number 30918012201).  
The authors declare no conflict of interest.