Ballistic Field Research Articles

Ballistic response of an airbag with parallel ribs under spherical projectile impact

The airbag-type inflatable structure with ribs was developed, composited from thermoplastic polyurethane (TPU) membranes. Ballistic impact tests were conducted on pre-inflated airbags to assess the airbag’s dynamic response. A set of Split Hopkinson Tensile Bar (SHTB) experiments were conducted on TPU membranes at strain rates ranging from 3000 to 12,000 s−1 to derive a strain-rate dependent constitutive model for TPU under ballistic impact conditions. Based on the fluid cavity inflation method, a finite element model was employed to analyze the structural response of the airbag. Based on the principle of energy conservation, an innovative theoretical model for the impact of airbags considering internal pressure has been established. The results indicate a strong agreement between the numerical, theoretical, and experimental results concerning the impact process and ballistic limit. It was observed that as the internal pressure rises, the ballistic limit of the airbag decreases. The theoretical model indicates that with an increase in internal pressure and the spacing of the center ribs, the initial strain energy of the membrane increases, leading to a decrease in the kinetic energy dissipation of the airbag to the projectile and subsequently reducing the ballistic limit of the airbag. This research provides a theoretical foundation and basis for the structural design and analysis of energy dissipation patterns in inflatable structures. It expands the potential applications of inflatable composite structures in the field of ballistics.

A comparison of gelatine surrogates for wound track assessment.

The use of ordnance gelatine has been widespread in the field of ballistics as a simulant for soft tissue when assessing ballistic threats. However, the traditional method of preparing ordnance gelatine is time-consuming and requires precision to ensure that the final mold meets the required specifications. Furthermore, temperature control is necessary post-production, and there are limitations on its usage duration. To address these issues, manufacturers have developed pre-mixed, gelatine-like products that are stable at room temperature and require less preparation time. Nonetheless, it is uncertain whether these new products can perform in the same manner as the gold standard of ordnance gelatine. This study used five types of blocks, including ordnance gelatine (10% and 20%), Clear Ballistics (10% and 20%) and Perma-Gel (10%) and subjected them to 9mm, 0.380 Auto fired from a universal receiver and a 5.56 × 45mm ammunition fired by a certified firearms instructor. Delta-V and total energy dissipation were measured after each test using data collected from ballistic chronographs placed in front of and behind each block. High-speed video was recorded, and a cut-down analysis conducted. The findings revealed variations in energy dissipation and fissure formation within the block, with greater energy based on fissure formation observed in the ordnance gelatine. Additionally, the high-speed video showed the occurrence of secondary combustions occurring in the premixed gelatines.

Compact Spice Models for Terafets

Field effect transistors (FETs) in plasmonic regimes of operation could detect terahertz (THz) radiation and operate as THz interferometers, spectrometers, frequency-to-digital converters and THz modulators and sources. We report on the development of compact models for Si MOS (Metal-Oxide-semiconductor) and heterostructure-based plasmonic FETs (or TeraFETs) suitable for circuit design in the THz range and based on the multi-segment unified charge control model. This model accounts for the electron inertia effect (by incorporating segmented Drude inductances), for the ballistic field effect mobility, which is proportional to the channel length, for parasitic resistances and capacitances and for the leakage current. It is validated by comparison with experimental data and TCAD simulation results. The model can be used for simulation and optimization of sub-THz and THz detectors. Our simulations use up to 200 segments in the device channel. The results are also in good qualitative agreement with the hydrodynamic simulations. Applications of our model could dramatically reduce astronomical design costs of nanoscale VLSI reaching US$1.5 billion for the 3 nm technological node.

THEORETICAL INVESTIGATION ON COMBUSTION HETEROGENEITY IN INTERIOR BALLISTICS OF MORTAR USING POPULATION BALANCE EQUATION

The ever-rolling progress of weapon systems has proven to demand an increase in precision in the models to be able to achieve further improvements. In the field of interior ballistics, one of the elements that remains excluded from most models is the combustion heterogeneity due to non-equilibrium of pressure. This paper presents a zero-dimensional model of a mortar. It includes two chambers: the combustion chamber and the cartridge with combustion heterogeneity occurring between these two chambers. The model adapted to this kind of problem is the population balance equation (PBE). A successful attempt to solve the PBE numerically in this case, using the class method, is presented in this work to theoretically address the quantification of the impact of combustion heterogeneities too often ignored.

Effect of the Same Sized Holes with Different Geometries and Angles in the Gun Silencer Diffusers on the Acoustic Power Level

The bullet, which is activated by the firing of the gunpowder in the gun silencer, comes out of the gun's barrel. In the meantime, an irritating muzzle blast sound is heard that lasts for a few milliseconds. With this explosion, acoustic sound waves are formed that are independent of the bullet's path of motion. In this study, a silencer that can be attached to a low-power 9 mm firearm is modeled. Afterward, the impact of holes with the same area drilled in different geometries and angles on the diffusers (compartments) of the silencer are compared. The Computational Fluid Dynamics (CFD) analysis method is used for this comparison. In addition, the dynamic mesh model is used where the ballistic field changes over time. This mesh model is analyzed for imperforate, circular-holed, square-holed, and triangular-holed profiles with the same area. Depending on the analyses, the pressure, velocity, and dB results obtained for the silencer outlet area are compared with each other.

AMMUNITION, EXPLOSIVES AND EXPLOSIVE DEVICES AS OBJECTS OF CRIMINAL ATTACKS IN THE COMMISSION OF A CRIMINAL OFFENSE UNDER ARTICLE 263-1 OF THE CRIMINAL CODE OF UKRAINE

One of the subjects of criminal encroachment in the commission of a crime under Art. 263-1 of the Criminal Code of Ukraine are ammunition, explosives and explosive devices. Such objects are capable of causing destruction, have the ability to cause bodily injury or death to a person and form significant material harm. At the present stage, in the absence of a basic law on weapons, in practice, there are certain problems with the qualification of the acts of persons as the illegal manufacture of ammunition, explosives and explosive devices. The article presents the concepts and types of these elements of the forensic characteristics of a crime under Art. 263-1 of the Criminal Code of Ukraine. The classification of ammunition, explosives and explosive devices makes it possible to differentiate a specific object as the subject of a crime under Art. 263-1 of the Criminal Code of Ukraine, to determine its forensically significant properties and characteristics. Particular attention is paid to traces that appear at the site of careless handling of ammunition, explosives and explosive devices. To inspect the sites of these incidents, it is imperative to involve specialists in ballistics, explosives specialists, as well as other persons with special knowledge in the field of ballistics and explosives. The presence of these specialists also ensures the safety of other participants in this investigative action. Ammunition, explosives and explosive devices as objects of criminal assault have a close relationship with the personality of the offender, the method of committing a criminal offence and the pattern of traces. Therefore, the establishment of the objects of criminal encroachment and their study allow you to correctly select the methods, techniques and means of investigation, determine the optimal sequence of investigative actions, and also properly ensure the investigation of a crime under Art. 263-1 of the Criminal Code of Ukraine. The article concludes with the importance of ammunition, explosives, and explosive devices for establishing the elements of a forensic characterization of a crime under Art. 263-1 of the Criminal Code of Ukraine, and the need to use the special knowledge of experts involved in the relevant criminal proceedings.

Ballistic Model of Two-Stage Light Gas Gun

A physical model and specificity of a two-stage light gas gun propulsion system are presented in this paper. For the considered system, a mathematical model of phenomena inside a combustion chamber, a light gas filled chamber, and a barrel was worked out. A numerical solution of the proposed model for the considered propulsion system gives pressures of powder gases, pressure of light gas, and motion parameters of a piston and a projectile. On the basis of the results of the accomplished calculations, influence of system structural parameters on the maximum pressure inside a compression chamber and a muzzle velocity of a projectile has been analysed. The final results of this work were used for development of the first in Poland a laboratory station with two-stage light gas gun intended for experimental investigation in the field of terminal ballistics of objects moving at hypersonic velocities.

Bullet Id: A Virtual Bullet Identification for Forensic Ballistics Students

As school is a public place where the crowd is unavoidable and children are vulnerable, there is a need to strengthen policy in terms of the delivery of instruction - to provide opportunities for online learning platforms. Numerous innovative programs have been proposed by the different learning sectors in the Philippines. The Commission on Higher Education suggested strengthening online platforms and blended learning such as but not limited to google classroom, messenger, zoom, Edmodo, Facebook, and YouTube. This study was conducted using the Agile Software Development Methodology. The Bullet ID is a promising educational tool that will help both instructors and students in their learning activities, especially in the field of forensic ballistics. This new learning technology will bridge the gap between face-to-face and online classes. The main feature of this system is that it is an offline-based mobile application which made it different from the other forensic ballistic application developed by other researchers which are computer-based software application that requires an internet connection.

Trajectory simulations by the numerical solution of the point-mass equations of motion for 7.62 mm/.308” rifle bullets

BACKGROUND: The understanding of the dynamics of the trajectory is important in ballistics to estimate the values of various flight variables accurately. The paper deals with the study of the fundamental principles of external ballistics, which allows to delve into the trajectory characteristics of the free flight trajectory of seven. 308 caliber bullets by numerically solving the point-mass equations of motion. Numerical solutions were performed by writing scripts in the Python programming language and using the Matplotlib library to plot simulated trajectories.
 AIM: the three aims of the study were to observe the variation of CD with Mach number (Ma) of flight and calculate an average CD for each bullet under consideration. Further, solving the 3-DoF (Degrees-of-Freedom) Point-Mass trajectory equations of motion for the given bullets (along side observing the effects of range winds on the trajectory behaviour as a variable). And finally, solving the flat-fire approximation with analysis of the effects of a crosswind.
 MATERIALS AND METHODS: Simulations of free-flight trajectories of seven different 7.62 mm/.308 rifle bullets (designated B0B6) have been carried out by the numerical solution of the equations of motion. The average drag force coefficients (CD) for B0B6 have been calculated by scaling the variation of CD with the Mach number of flight with reference to the G7 standard projectile. The Point-Mass trajectory model and its Flat-Fire approximation have been studied with and without the effect of range winds. The solutions of the systems of equations have been carried out by writing scripts in the Python programming language.
 RESULTS: It is observed that an increase in the bullet weight and consequently the sectional density lowers the CD. As expected, it is seen that the bullet with the highest drag (B0) has the shortest range and lowest apogee, while lower drag bullets fly further and higher. The crossover of trajectories is observed at ~30 angle of gun elevation, which implies that the maximum range is not achieved when fired at 45, as is the case with vacuum trajectories. Flat-fire approximation of the point-mass model was also solved to observe trajectories and crosswind deflections of the bullets when fired at 5 angles of elevation.
 CONCLUSION: This project presents the numerical solution of equations of motion of the Point-Mass model for a bullet fired from a gun to computationally simulate its trajectory. A group of seven 7.62 mm/.308 rifle bullets were chosen as samples to simulate free-flight trajectories. The programming language Python is well-equipped to carry out numerical solutions of systems of differential equations owing to its library of in-built functions which assists in writing an efficient script and reduces computational load. This method of solution can be applied with suitable modifications in the field of forensic ballistics for the reconstruction of bullet trajectories and to form a conclusion based on the available evidence from a crime scene.

Данные об истории замедления тела в реологической среде как основа для верификации расчетных задач

Relying on data on the history of body deceleration during high-speed penetration into the target, the paper reviews the Proceedings of the 23rd – 31st International Symposiums on Ballistics, as well as the findings in the field of terminal ballistics, i.e. the study of body acting on a target, and the history of striker deceleration in the target material. The paper observes a half-century path of development of the technology as a new scientific direction, started in the department of High-Precision Airborne Devices at Bauman Moscow State Technical University. Strikers in measuring technology are equipped with shock accelerometers and original electrical recorder communication systems. Theoretical and experimental studies revealed a new law of medium penetration resistance. The law allows the use of engineering methods to solve problems, e.g. spatial problems of penetration. The data on the history of the measuring striker deceleration recorded in the experiments provided additional opportunities for verifying the models and the results of virtual simulation of the processes of spatial penetration. The paper introduces the studies carried out by the authors in a wide range of different initial conditions of impact and designs of strikers and targets. New technical solutions in measuring technology developed recently are also presented.

ОБҐРУНТУВАННЯ НЕОБХІДНОСТІ ВДОСКОНАЛЕННЯ НАУКОВО-МЕТОДИЧНОГО АПАРАТУ ФОРМУВАННЯ ВИМОГ ДО ЕНЕРГЕТИЧНИХ ХАРАКТЕРИСТИК ПОРАЖАЮЧОГО ЕЛЕМЕНТА КІНЕТИЧНОЇ ЗБРОЇ НЕСМЕРТЕЛЬНОЇ ДІЇ

The scientific-methodical apparatus for predicting damage to biological objects of non-lethal kinetic weapons is considered, which mainly takes into account only the energy characteristics of the damaging elements, namely, kinetic and specific energy. An analysis of the nominal ballistic characteristics of samples of non-lethal kinetic weapons, which are in service with law enforcement agencies and military formations of Ukraine, was carried out, based on the determination of only the specific energy of the striking elements. The energy characteristics of bullets or striking elements for various samples of non-lethal kinetic weapons vary within fairly wide limits. In particular, such an important indicator as the specific energy varies from 0.34 to 1.33 J/mm2, that is, even the same type of weapon, intended for use at certain distances to the target, in the case of using different cartridges, has a significantly different specific energy (the difference reaches 30%). An analysis of known developments in the field of terminal ballistics is given, which indicates the need to take into account the speed of meeting the target under the conditions of conservation of constant kinetic energy. So, with the same mass, a bullet with a higher speed will have more energy. Such a ball has the ability to give a different part of its energy to the affected tissues. The main feature of cartridges with a traumatic effect, which distinguishes them from ordinary cartridges for firearms, is the mechanical characteristics of the striking elements. The striking elements require a high "stopping" effect, i.e. quick and complete incapacitation of the opponent when hitting any part of the body - this is a short range of "fire contact". For this, striking elements must quickly and maximally transfer their kinetic energy to the target upon hitting it. Therefore, most bullets for police and civilian weapons are blunt-end ("impact") - with a rounded or flat area on the main part. So important are the shape and strength (stiffness) of the striking elements and the shape of the main part that directly interacts with the target. The need to improve the scientific and methodological apparatus for predicting damage to biological objects when using non-lethal kinetic weapons by taking into account an expanded list of factors (speed, strength, rigidity and shape of the striking element) in order to increase the adequacy of the obtained models is substantiated.

Impact and Ricochet of a High Speed Projectile from a Plate

A computational study of a projectile (either 2024 aluminum or TiAl6V4 titanium alloy) impacting a plate (either titanium alloy or aluminum) is presented in this paper. Projectile velocity (ranging from 250 m/s to 1500 m/s) with varying impact angles are considered. The presence of ricochet (if any) is identified over the ranges of the projectile velocity and impact angle considered. For the cases where ricochet is identified, the ricochet angle and velocity are predicted as functions of the incident angle and the incident velocity. The numerical results are compared with an analytical solution of the ricochet problem. The analytical solutions are from a model developed to predict the ballistic ricochet of a projectile (projectile) penetrator. The dynamics and the deformation of an aluminum (or a titanium alloy) projectile impacting on a finite thickness titanium alloy (or aluminum) plate are simulated. The current work is interesting in that it looks in the field of ballistics of different material combinations than are traditionally studied. The present simulations based on detailed material models for the aluminum and the titanium alloy and the impact physics modelling features in the LS-DYNA code provide interesting details regarding the projectile/plate deformations and post-impact projectile shape and geometry. The present results indicate that for no cases (for specified incoming velocities and impact angles considered) can an aluminum projectile penetrate a titanium alloy plate. The ricochet ‘mode predictions ‘obtained from the present simulations agree well with the ricochet ‘mode predictions’ given in an analytical model.

Experimental and numerical investigation on the ballistic resistance of ZK61m magnesium alloy plates struck by blunt and ogival projectiles

• Ballistic tests on 5 mm thick Zk61m magnesium alloy plates struck by blunt and ogival rigid projectiles were conducted. • Introduced the Lode angle into the JC plasticity model to characterize the stress flow behaviour of the Zk61m magnesium alloy. • The value of incorporating the Lode parameter into the plasticity model and fracture criterion in the ballistic resistance of the magnesium alloy was reflected. • A unique failure pattern was discovered when an ogival projectile was used to impact the target. In the field of ballistics, Johnson-Cook (JC) plasticity and fracture models have provided a good theoretical basis for the prediction of ballistic performance by capturing the essence of ductile metal fracture. Nevertheless, the JC model cannot accurately reproduce the fracture behaviour of some metals. Many Lode parameter-dependent fracture criteria have effectively improved this deficiency, indicating that the fracture loci of these metals are Lode-dependent, even though the flow stress behaviour is stress state dependent, which cannot be well characterized by the JC plasticity model. In this paper, a series of mechanical tests and parallel numerical simulations of ZK61m magnesium alloy were conducted. The results showed that the flow stress behaviour and fracture loci of the alloy were obviously Lode dependent. Therefore, it seems insufficient to evaluate only the necessity of incorporating Lode parameter into a fracture criterion in predicting ballistic performance of ZK61m magnesium alloy, and more investigations on the influence of Lode parameter on the plasticity behaviour of the material should be carried out. In the present work, ballistic tests were conducted on 5 mm thick ZK61m magnesium alloy plates using blunt and ogival nose shaped projectiles with a nominal diameter of 12.68 mm. The targets failed by shear plugging when impacted by blunt-nosed projectiles, but caused a unique failure pattern under the impact of ogival-nosed projectiles. Lode-dependent plasticity model and fracture criterion were adopted. Better prediction accuracy was observed when Lode parameter is considered in both the plasticity model and fracture criterion simultaneously.

Research on the Chamber Pressure Test Method of Small Caliber Weapons Based on a Double-Layer and Double-Grid Structure Strain Tester

Chamber pressure test remains to be a difficult problem in the field of internal ballistics. Therefore, a new chamber pressure test method based on a double-layer and double-grid structure strain tester was proposed to test the chamber pressure for the small caliber weapons. The method has a simple design structure compared with the traditional chamber pressure test method. This method can also obtain the entire pressure test curve without destroying the barrel structure. Furthermore, the novel method has a high test accuracy with low cost, high reliability with long life, and good electromagnetic compatibility (EMC). The core idea was to test the strain on the outer wall of the barrel through the double-layer and double-grid strain tester, thereby calculating the chamber pressure according to thick-walled cylinder theory. First, the mechanism of this new test method was analyzed, and the fourth-order Runge-Kutta algorithm was used to establish a simulation model of the chamber pressure. Second, the sensitivity of the strain tester was obtained by calibrating the strain test system. The test method was compared with the lead wire electronic manometer test and the simulation modeling methods. The test curve was consistent with the lead wire electronic manometer test and the simulation curves, verifying the test accuracy and feasibility of the method. Finally, the simulations and experiments validated that the new test method had good EMC.

Analysis of projectile-barrel coupling vibration characteristics considering the radial effect of propellant gas pressure

In view of the influence of projectile-barrel coupling on tank firing accuracy, a finite element model of projectile-barrel coupling based on vibration theory was established. By defining user subroutines to simulate the change of the physical field of interior ballistics, the load condition under which the propellant gas radial pressure acts on the inner wall of the barrel and varies with the motion of the projectile is realized. On this basis, the dynamic characteristics of projectile-barrel coupling considering the radial effect of propellant gas pressure were studied. The reference targets such as cradle, projectile and muzzle were selected for analysis, and compared with the situation without considering the radial effect of propellant gas pressure. The results show that the motion trend of the projectile in the bore and the response law of muzzle vibration change greatly when considering the radial effect of propellant gas pressure and these changes may seriously affect the law of projectile dispersion. The radial effect of propellant gas pressure can cause stronger dynamic response, which cannot be ignored in the simulation of artillery firing process. This work provides a practical reference for further study of tank firing accuracy.

Detection of gunshot residue particles from barrel swab by ultra-sensitive x-ray fluorescence spectrometry

Gunshot residue (GSR) plays a crucial role in the field of forensic ballistics. GSR is a vital link between the firearm and firing. By examine the GSR particles, the use of the firearm in a shooting incidence can be confirmed. The GSR present inside the barrel of a firearm commonly known as barrel swab is very important evidence to connect a firearm with the incident. The estimation of GSR present inside the barrel is generally carried out by chemical methods. Although, the elemental analysis of characteristic elements (i.e., lead, barium, and antimony) using AAS provides good result but has number of drawbacks which include sample preparation, detection limit and digestion of sample.

CRIMINALISTICS ASPECTS OF THE STUDY BALLISTIC CHARACTERISTICS AND STRIKING PROPERTIES OF BULLETS OF PISTOL CARTRIDGES OF 9 × 21 IMI CALIBER

The article presents data based on the results of experimental studies on the external ballistics parameters and the nature of changes in the trajectory of the kinetic energy of four types of pistol cartridges bullets 9 × 21 IMI (9 × 21 mm.), which were shot from two samples of carbines with different lengths of the rifled part of the barrel. Of particular interest are data on the nature of the shell interaction and expansive bullets of cartridges of the indicated caliber with the tissues of a biological object, the imitation of the interaction with which was carried out using ballistic testing backing material (ballistic clay). The use of a simulator of biological tissues of the human body made it possible to determine the features of the shock-contact interaction of shell and expansive bullets with them, as well as to establish the nature of the behavior of these bullets in the thickness of a viscoelastic medium. It was experimentally found that under certain conditions, 9 mm jacketed bullets are capable of inflicting through wounds to the human body at firing distances up to 25 m inclusive, while the bullet, after breaking through the barrier, has energy characteristics that are sufficient to inflict a penetrating injury of varying severity on another biological object. Due to the use of ballistic clay, it became possible to visualize the maximum amount of damage caused by shell and expansive bullets, as well as to determine the features of the formation of exit wounds, taking into account the destabilization of shell bullets in the thickness of the obstacle. It should be noted that at firing distances up to 5 m inclusive, shell bullets, due to the loss of gyroscopic stability in the tissues of a biological object, which have a sufficiently large thickness, are capable of inflicting wounds, the volume and severity of which are comparable to or exceed the corresponding parameters of wounds caused by expansive bullets. The obtained results of measurements of the velocity of the of shell bullets after overcoming an obstacle in the form of a viscoelastic medium can later become the basis for calculating the contact speed of a bullet with a known length of the channel of the inflicted wound. The article for the first time presents the calculated data on the parameters of the flight path of shell and expansive bullets of pistol cartridges 9 × 21 IMI (9 × 21 mm.) at firing distances up to 100 m. The presented results of experimental studies and calculated data will allow experts in the field of forensic ballistics and forensic medicine to solve the tasks set by the pre-trial investigation authorities. Key words: ballistic clay, biological object, elements of the trajectory of a bullet flight, carbine, pistol cartridge, wound, wound channel, damaging properties, damage.

Volcanic ballistic projectile deposition from a continuously erupting volcano: Yasur Volcano, Vanuatu

Volcanic ballistics are the main hazard to life and infrastructure from Strombolian eruptions, which are a tourist drawcard, exposing people to this hazard. Most research to date has been to understand this style of eruption and how ballistics form and travel. However, little focus has been placed on how ballistics are distributed within ballistic fields or the inclusion of this data into hazard and risk assessments. In this study we used a UAV to image the ballistic field, and cameras to record eruptions at Yasur Volcano, Vanuatu from 28 July – 2 August and 17 – 19 October 2016. We present the mapped distributions from the two trips, how the field changes with distance and direction from the vent, and how eruption dynamics influence these changes. Our evidence for directionality results in considerable variation in summit ballistic hazard and is an important consideration for ballistic hazard and risk assessments.

Visualizing Poiseuille flow of hydrodynamic electrons.

Hydrodynamics, which generally describes the flow of a fluid, is expected to hold even for fundamental particles such as electrons when inter-particle interactions dominate1. Although various aspects of electron hydrodynamics have been revealed in recent experiments2-11, the fundamental spatial structure of hydrodynamic electrons-the Poiseuille flow profile-has remained elusive. Here we provide direct imaging of thePoiseuille flow of an electronic fluid, as well as a visualization of its evolution from ballistic flow. Using a scanning carbonnanotube single-electron transistor12, we image the Hall voltage of electronic flow through channels of high-mobility graphene. We find that the profile of the Hall field across the channel is a key physical quantity for distinguishing ballistic from hydrodynamic flow. We image the transition from flat, ballistic field profiles at low temperatures into parabolic field profiles at elevated temperatures, which is the hallmark of Poiseuille flow. The curvature of the imaged profiles is qualitatively reproduced by Boltzmann calculations, which allow us to create a 'phase diagram' that characterizes the electron flow regimes. Our results provide direct confirmation of Poiseuille flow in the solid state, and enable exploration of the rich physics of interacting electrons in real space.

Plasmons in Ballistic Nanostructures With Stubs: Transmission Line Approach

The plasma wave instabilities in ballistic Field Effect Transistors (FETs) have a promise of developing sensitive THz detectors and efficient THz sources. One of the difficulties in achieving efficient resonant plasmonic detection and generation is assuring proper boundary conditions at the contacts and at the heterointerfaces and tuning the plasma velocity. We propose using the tunable narrow channel regions of an increased width, which we call "stubs" for optimizing the boundary conditions and for controlling the plasma velocity. We developed a compact model for THz plasmonic devices using the transmission line (TL) analogy. The mathematics of the problem is similar to the mathematics of a TL with a stub. We applied this model to demonstrate that the stubs could effectively control the boundary conditions and/or the conditions at interfaces. We derived and solved the dispersion equation for the device with the stubs and showed that periodic or aperiodic systems of stubs allow for slowing down the plasma waves in a controllable manner in a wide range. Our results show that the stub designs provide a way to achieve the optimum boundary conditions and could also be used for multi finger structures - stub plasmonic crystals - yielding better performance of THz electronic detectors, modulators, mixers, frequency multipliers and sources.