Mechanical Properties And Equivalent Test Method Of Si Based Chips In Penetrating Environment

In modern warfare,penetrator-type weapons play a crucial role in urban combat and armor-piercing attacks.However,due to the increasing protection of high-value targets,integrated circuit modules within penetrator-type weapons face problems such as device damage,circuit malfunctions,and even failure,which seriously affects the penetration effectiveness and reliability of such weapons.This article focuses on Si-based chips inside penetrator-type ammunition,analyzes their mechanical characteristics in penetration environments,studies the distribution of stress on the chips based on polyurethane encapsulation materials,and explores improved equivalent test methods for i MPact overload.The main research contents are as follows:(1)Studying the penetration environment and simulation test method of Si-based chips.Co MParing and analyzing various algorithms of ANSYS/LS-DYNA software for dealing with continuum,and focus on the Lagrange algorithm.35CrMnSiA and 45 steel were selected as the penetrating projectile and target material respectively.The material model is established by the Cowper-Symonds model and the Johnson-Cook model.By simulating the projectile at different initial velocities and different penetration angles,the acceleration-time curve,equivalent stress change cloud map,and node stress curve of the internal cavity of the projectile are obtained.Based on the simulation results,the stress distribution of the internal cavity where the missile Si-based chip is located is analyzed under the penetrating environment.(2)The transient response of Si-based chips in penetrating environments is analyzed using the shock response spectrum method.Three types of response spectrum characteristics are co MPared to determine the best method for analyzing the pseudovelocity shock response spectrum.The first 20-order modal analysis of the Si-based chip is carried out,and the result shows that the axial natural frequency of the Si-based chip is 13861 Hz,which is verified by harmonic response analysis.A spring-mass model and a beam model were established for Si-based chip components for dynamic analysis,and it was calculated that the chip damage boundary was at the solder joint.Its critical displacement is 0.119μm,critical velocity is 1.37m/s,and critical acceleration is 23875.6g.And the damage boundary is drawn on the pseudo-velocity shock response spectrum,and verified by numerical analysis.(3)Analyze the protection ability of potting materials for Si-based chips,study the propagation law of stress waves in chip potting materials,co MPare the viscoelastic stress models,analyze the propagation process of stress waves in one-dimensional viscoelastic rods,and derive The stress attenuation formula was derived,and the preparation method,foaming process and potting process of the polyurethane potting material were analyzed,and the relevant parameters of the stress decay formula of the synthesized polyurethane potting material were obtained.Combined with the expression,it can be concluded that the stress wave is more attenuated in the thickness range of 0～20 cm of the polyurethane potting material,and the greater the density of the polyurethane potting material in the range of 0.036g/cm~3～1.272g/cm~3,the protection ability of the Si-based chip stronger.Finally,the equivalent test principles were analyzed and the i MPact overload equivalent test was improved.At the same time,design and improve the drop test and the Marshall i MPact test,and collect the acceleration data of the inner cavity where the Si-based chip is located through the manufactured accelerometer.The acceleration data of the improved drop test and the improved Marshall test and the Si-based chip damage boundary is plotted on the pseudo-velocity shock response spectrum,and co MPared with the Si-based chip failure.The results of numerical simulation and theoretical analysis are verified.