Constant Cross-sectional Area Research Articles

Analytical and Experimental Study of the Start of the Chip Removal in Rotational Turning

The present challenges in the automotive industry require the development and practical implication of novel machining procedures, which will provide appropriate solutions. These procedures should still meet the requirements of productivity, surface quality and energy efficiency. The further development of novel machining procedures introduces new problems that did not occur (or occurred to a lesser extent) with traditionally applied procedures. Rotational turning has come to the attention of production engineers in the previous decade since it can be used to machine ground-like surfaces in an ecologically friendly and highly productive manner. However, the chip removal characteristic is slightly different from traditional turning due to the applied special kinematic relation and complex tool edge geometry. The run-in phase will take longer, which is the time period between the first contact of the tool and the formation of a constant chip cross-sectional area. The clarification of the chip formation is important in any machining procedure. To achieve this goal, the geometric parameters of the chip must be determined. Since the start of the chip removal is a crucial stage in rotational turning due to its length, the chip height, chip width and the cross-sectional area of the chip should be separately defined in the initial stage. Therefore, in this paper, the initial phase of chip removal in rotational turning is studied. The increasing cross-sectional area of the chip is determined analytically by the application of the previously elaborated equation of the cut surface. Calculating formulas are defined for the different stages of the start of the chip removal, which could be used in the forthcoming studies to analyze the chip formation. The effects of different determining parameters are analyzed theoretically by the deduced formulas of the run-in phase and practical experiments are also carried out. The analytical and experimental analyses showed that increasing feed also increases the dynamic load on the cutting edge, while the depth of cut lowers the growth of the characteristic parameters of the chip, which results in a lower dynamic load on the tool.

Performance Evaluation of Different Rotating Detonation Combustor Designs Using Simulations and Experiments

Abstract Rotating Detonation Engines (RDEs) present a potential avenue for enhancing the efficiency of gas turbine combustors through the utilization of a detonation-driven process. However, integrating an RDE with a downstream turbine poses a significant challenge due to the shock-laden and highly unsteady nature of the RDE exit flow, coupled with a high degree of flow periodicity. In contrast, gas turbines are designed to operate with relatively small velocity and temperature fluctuations at the turbine inlet. The objective of the present study is to develop an understanding of how geometric profiling can improve RDE performance and mitigate exhaust flow field unsteadiness. Three RDE designs are analyzed: an annular combustor with a constant cross-sectional area, an annular combustor with a converging nozzle near the exit, and an annular combustor with a rapid to gradual (RTG) area convergence. Three-dimensional unsteady reacting simulations are conducted for each configuration using the same fuel-oxidizer composition and mass flow rate condition. All simulations are validated against experimental measurements, and RDE performance is assessed based on total pressure gain/loss, unsteadiness at the exit of the RDE, and detonation effectiveness. Results show significant performance improvement for both the convergent nozzle and the RTG profile compared to the constant cross-sectional area configuration, and the RTG design performed better than the convergent nozzle design. Therefore, strategically constricting the flow in an RDE can be used to optimize the performance of an RDE and should be considered in future designs.

Computational modeling and statistical analysis of buckling characteristics of polysilicon reinforced fiber

The purpose of this study is to evaluate the effect of volume fraction of continuous carbon fiber and sample length on buckling characteristics of polysilicon. A statistical design of 12 samples were formulated with constant cross-section area of 2500 mm2 using Design of Experiment software (DOE). The samples were sketched using ABAQUS 2019 software, and the total buckling force each sample was estimated. The estimated buckling forces were statically evaluated as a response using DOE. The estimated forces of 3.48776e07, 4.00652e07 and 5.78142e07 newton for the simulated samples of 100 mm in length and 0,15, and 25% volume fraction respectively, is an indication of positive effect of fiber volume fraction on the necessary force for buckling. In addition, similar tendency was found in other samples (the higher fiber volume fractions the higher buckling force). However, the estimated buckling force for each sample was negatively affected with length of the sample. The result indicated a value of 4.00652E+07, 5.00447E+06 and 1.80390E+06 newton at a constant fiber volume fraction and different length of 100, 300 and 500 mm respectively. The statistical analysis of the simulated buckling force showed a signification design, and the date of one factor effect is highly supported by the simulated buckling forces. The equation of a significant design can be used to estimate the buckling force at any fiber volume fraction and sample length.

Effect of Porosity on Combustion Performance in Packed Bed Porous Media

This study investigates the effect of packed bed material porosity and air-to-fuel ratio on the combustion stabilization of a premixed gaseous mixture. An experimental work was carried out in a single-layer concept of a packed bed on a constant cross-sectional area tubular burner. Two types of materials, Alumina (Al2O3) and Zirconia (ZrO2), with different porosities, namely 0.36, 0.4, 0.44, and 0.46, were tested. The results showed that porosity has a significant effect on the position of the reaction zones. As porosity decreases, the reaction zone moves downstream of the packed bed. The excess air ratio does not affect the position of the reaction zone but has an impact on the temperature distribution inside the porous medium. The packed bed material affects the volume of the reaction zone and the temperature distribution inside the porous media, where Zirconia has a reaction zone volume higher than Alumina. The concentration of NOx was reduced with increasing porosity. Zirconia media exhibits a lower level of NOx emission compared to Alumina. For an excess air ratio of 1.6, the maximum NOx values were 22.5 and 17.5 ppm for Alumina and Zirconia, respectively.

A criterion of dimensional design to improve flame spread resistance of magnesium alloy components

A criterion for predicting the flame spread time of stick-shaped Mg alloy samples was proposed based on the law of energy conservation. It is indicated that the flame spread time is mainly affected by the material and sample dimension. The initial temperature and ignition temperature of the control volume and the S/lc ratio (the cross-sectional area/cross-sectional circumference) of the sample are decisive for the flame spread time. The flame spread time is proportional to the ΔH (the energy required to heat a unit mass of sample from initial temperature to ignition temperature) and the S/lc ratio, which is confirmed in three Mg alloys of Mg–8.5Al–0.5Zn–0.2Mn, Mg–2.7Nd– 0.4Zn–0.6Zr and Mg–4.0Y–3.3Nd–0.5Zr. For samples with the same dimension, the Mg–8.5Al–0.5Zn–0.2Mn alloy sample possesses the largest ΔH and the longest flame spread time. For samples with constant length and cross-sectional area, the sample with circular cross-section has the largest S/lc ratio and the best flame spread resistance in the same alloy.

Effect of thickness on fatigue behavior of L-PBF fabricated Ti-6Al-4V alloy using a novel specimen geometry

One of the most promising advantages with additive manufacturing is the ability to fabricate complex geometries. These geometries can have significant impacts on thermal histories, microstructures, defects, and fatigue behavior. This study aims to investigate the effects of thickness variation on the fatigue life of AM fabricated components subjected to uniaxial loading through the introduction of a novel specimen geometry. The geometry is designed with a constant cross-sectional area and varying thicknesses by changing the diameter, ensuring constant stress throughout the gage section. Results found minimal relationship between the thickness and fatigue behavior for the as-built surface condition.

Alleviation of micro-pressure waves radiated from tunnel hoods

When a train enters a tunnel, an impulsive pressure wave, called a micro-pressure wave (MPW), radiates from the tunnel exit. The MPW causes infrasound and audible noise near the tunnel portals; therefore, it should be reduced for environmental reasons. A typical countermeasure is the installation of a hood at the tunnel entrance portal. In a previous study, we proposed a new type of hood that combined two hoods with constant and different cross-sectional areas (a two-step hood). The two-step hood was more effective than the existing hoods. However, because the cross-sectional area of the portal of the two-step hood was larger than that of the existing hoods, the MPW radiated by a train entering the opposite tunnel portal increased in a double-track tunnel. This study developed a new concept for a tunnel hood that reduces the radiated MPW (performance at the MPW radiation stage) while maintaining the performance in terms of reducing the maximum pressure gradient of the compression wave (CW) generated by a train entering a tunnel (performance at the CW generation stage). The desired specifications for satisfying both performances were determined through calculations based on acoustic theory, and their performances were investigated through model experiments using a train model launcher. As the results, the desired specifications were lh3/lw>0.6, lh1≈lh2>lwMt/1-Mt, σh1=1.4, and σh2=2.5, where lh1, lh2, and lh3 are lengths of first hood, second hood, and added lateral wall, respectively, lw is wavefront thickness, Mt is the train’s Mach number, and σh1 and σh2 are the cross-sectional area ratio of the first and second hoods to tunnel, respectively. The developed hood is expected to provide more effective performance in mitigating MPW than existing hoods.

Analysis of self-supporting conformal cooling channels additively manufactured by hybrid directed energy deposition for IM tooling

Additive manufacturing (AM) of injection moulding (IM) tools has attracted significant interest in the polymer manufacturing industry for quite some time. However, hybrid manufacturing (HM) using directed energy deposition (DED), which involves concurrent additive and subtractive manufacture, has not been a commonly used process for IM tooling manufacture. This is apparent despite several advantages over the prevalent laser-powder bed fusion (L-PBF) alternative, including higher build rate, lower cost and integrated machining to directly achieve higher tolerances and surface finish. A key reason for this low utilisation is the limited ability of DED processes to produce circular channel profiles typically used in IM tooling, due to stricter constraints on the manufacturability of overhanging geometry. To address this, a range of self-supporting IM cooling channel profiles suited for hybrid laser and powder-based DED manufacture are proposed in this work. Numerical and experimental evaluations are conducted of the cooling performance of several non-circular conformal cooling channel (NCCC) profiles to identify a profile which achieves the maximum heat transfer for a constant cross-sectional area and coolant flow rate. Experimental studies included AM builds to evaluate the DED manufacturability of the selected NCCC profile on a conformally cooled HM benchmark model, followed by cooling performance characterisation, including a comparison against a reference L-PBF manufactured benchmark model. In conclusion, a shape correcting factor is obtained using response surfaces. This factor is used to convert thermal performance calculations for non-circular profiles to a conventional circular channel profile to simplify the DED manufacturing process for non-circular IM cooling channels.

Experimental investigation of blade-shaped riblets for drag reduction on UAV applications

This study presents an experimental investigation of blade-shaped riblets for drag reduction in unmanned aerial vehicle (UAV) applications. UAVs have gained significant attention since they can perform various missions, including surveillance, reconnaissance, and package delivery. However, their aerodynamic performance, specifically the high drag associated with their exposed surfaces, remains a key challenge for enhancing their efficiency and extending their flight endurance. To address this issue, riblet geometries are proposed as a potential solution, which can reduce the turbulent skin friction drag by up to 8%. The experimental investigation involves wind tunnel testing of blade-shaped riblets, with various spacing-to-height (s/h) ratios and constant groove cross-sectional area (Ag). The riblets are designed for application on the wing, empennage, and fuselage surfaces of a UAV. The investigations are performed on a flat plate for various flow conditions, including different freestream velocities, to evaluate the drag reduction effectiveness of the riblet configuration. The drag force is measured using a force balance system and flow visualization techniques are employed to assess the position where the boundary layer has transitioned to fully turbulent. The results demonstrate the drag-reducing effect of blade-shaped and trapezoidal riblets and the different performances observed for the various s/h ratios. The cases with s/h=1 result in the smallest drag coefficients, while the cases with s/h=2 have significantly increased drag values, compared to the smooth flat plate, due to the increased wetted surface area. These findings highlight the potential of riblets as an effective drag-reduction technique for UAV applications, enabling increased endurance and/or enhanced payload capacity.

Thermal performance enhancement of multiple tubes latent heat thermal energy storage system using sinusoidal wavy fins and tubes geometry modification

In this paper, performance enhancement of a shell and multiple tube latent heat thermal energy storage system (LHTESS) is numerically investigated by implementing sinusoidal wavy fins and different geometrical designs of heat transfer tubes. The annular space of the shell is filled with the paraffin wax RT35 as phase change material (PCM) and absorbs heat from hot water through the multiple tubes. With the constant total cross-section area of all tubes and fins as the constraint condition, the effect of tube number and tube shape incorporated with the proposed fins on the heat transfer properties of PCM during the melting process is evaluated. The computational results demonstrate that the sinusoidal wavy fins can improve the phase change efficiency compared to the conventional straight fins. The double-pitch sinusoidal wavy fins decrease the total melting time by 9.5% compared to the straight fins for the single-tube case. As the number of HTF tubes increased from one to four, the complete PCM melting time decreased by 38.3%. Geometrical design alterations of heat transfer tubes from circular to petal-shaped are proposed to further improve the thermal performance of multiple tubes LHTESS. The melting rate of PCM is accelerated with an increase in the number of petals. The petal tubes with nine petals can save the charging time up to 24 % in comparison with the circular tubes in a four-tube case with double-pitch sinusoidal wavy fins, and up to 57% compared to the base case with a single circular HTF tube and straight fins.

On the stability of elastic structures subjected to follower forces

Within the framework of a second-order theory, this study revisits classical stability problems characterized by critical loads associated with dynamic instability, previously explored by Feriani and Carini (in: Zingoni (ed) Insights and innovations in structural engineering, mechanics and computation, 2016) . The primary focus remains on systems exclusively comprising a single lumped mass. This simplification, together with the assumption of a negligible axial strain and the adoption of a second-order theory, reduces the analysed systems to problems featuring a single Lagrangian coordinate. Consequently, static methods become applicable, facilitating the derivation of analytical expressions for stiffness coefficients and enabling an investigation into dynamic stability. The study begins by examining a well-established case: a cantilever beam with a lumped mass positioned at its free end, subjected to a follower load, as presented in Panovko and Gubanova (Stability and oscillations of elastic systems: models, paradoxes and errors, Nunka Press, Moscow, 1967). In this current work, a novel lumped mass system is explored. The system consists of a straight-axis beam characterized by a constant cross-section area and stiffness. The distributed mass of the beam is neglected and the beam is hinged at one end, simply supported at an intermediate point, and left free at the other end, where a lumped mass is introduced. Various loading scenarios are scrutinized, including: (a) The application of a follower force to the free end; (b) The imposition of two forces—one conservative and one follower—both applied to the free end; and (c) The application of a uniformly distributed follower force along the length of the beam. As seen in the examples introduced in Feriani and Carini (2016), the new examples considered in the present paper reveal that the first asymptote of the stiffness coefficient corresponds to the critical load. This critical load corresponds to the phenomenon known as divergence at infinity, as described by Felippa (Nonlinear finite element methods, 2014). It is also confirmed that, in all cases, the first dynamical critical load equals the minimum value between the static buckling load of the original structure and the static buckling load of an auxiliary structure. This last differs from the original one because the concentrated mass is replaced by a constraint fixing the corresponding Lagrangian coordinate.

Research on parameterized modeling and mechanical characteristics of shearer cables.

Shearer cables, subjected to large deformations and exposed to harsh working conditions during frequent back-and-forth movements, pose difficulties in achieving comprehensive mechanical performance and extended fatigue life. This study addresses parametric modeling challenges related to determining tangency within and between layers, recursively generating spiral curves from the (n-1)-th level to the n-th level, and constructing irregular surfaces for insulation and sheath. Investigating tensile and bending properties, the research explores the impact of varying pitch diameter ratios at different stranding levels, stranding directions, and monofilaments on mechanical performance across scales. The results reveal a nonlinear increase in stress in power and control conductors with growing pitch diameter ratios. The optimal combination is determined as a pitch diameter ratio of 6 for cabling, 5 for the control conductor, and 14 for the power conductor. The predicted fatigue life of the improved cable by Ncode aligns with bending test results, demonstrating functionality up to 15.12e4 cycles. Stress distribution in parallel stranding is lower and more even, tending to scatter. Conversely, counter stranding experiences relatively higher stress, ensuring a more stable structure. While maintaining a constant effective conductor cross-sectional area, finer monofilaments result in higher cross-sectional filling ratios, enhancing tensile and bending performance.

Cavitation in Internal Flows of Liquid Jet Through a Throat

The interaction of a liquid with the surrounding air produces unstable waves that disintegrate the liquid into droplets, which is known as liquid atomization. The common internal flow of a liquid atomization nozzle experiences a single-phase flow but might turn into a multiphase flow with the existence of cavitation. Cavitation in internal flow has gotten a lot of attention because of the positive and negative consequences it can have depending on the application. One such advantageous result is that cavitation has been used to promote the atomization of liquid jets by causing gas bubbles in the atmosphere to collapse. Most of the past research on cavitation has focused on the exit orifice’s constant cross-section area. The current study investigates the effect of throat location and geometry on cavitation characteristics. Filtered water was used as the simulation fluid. The high-speed shadowgraph technique was applied to record the images of the internal flow patterns. The placement of the throat was discovered to have a substantial impact on the status of the cavitation. Cavitation began at the inlet of the throat when the throat was placed at the uppermost part of the exit orifice. However, when the throat is placed in the middle of the exit orifice, the cavitation begins at the end of the throat. Four cavitation regimes were identified, namely developing, mixed, super and sudden expansion cavitation. Furthermore, it was found that the discharge coefficient depends on the cavitation’s state and length, except when the cavitation is in the supercavitation regime.

Theoretical Analysis for Condensation Heat Transfer Performance Inside Converging-Shaped Microchannel Under Varying-Gravity Conditions

Abstract The fast increasing heat-dissipation requirements under different working conditions such as varying gravity for aerospace industry is drawing more and more attention. Condensation inside microchannel is proved to be a promising technique to tackle this task. To comprehensively and accurately describe the physical phenomenon, a theoretical method considering both momentum exchange caused by vapor condensation and interface temperature drop is developed in this study. Reliability of our theoretical method is verified with both the Comprehensive Shah Correlation and established data. Condensation heat transfer inside converging-shaped microchannel is investigated and the influences of channel size, refrigerant mass flowrate, gravity variation, and converging angle are considered. Converging-shaped microchannel significantly enhances condensation heat transfer, especially for smaller channel with larger refrigerant mass flowrate. Influence of gravity change on condensation performances of vertically configured microchannels both with converging shape and constant cross-sectional area is small.

Quantification of mechanical properties in long-term in vivo used silicone catheter lines according to DIN 10555-3

BackgroundTotally implantable central venous access port devices are crucial for intravenous application of chemotherapeutics and long-term therapy for chronic disease. Common complications include thrombosis and device fracture related to altered material properties through exposure in situ. This study exhibits whether uniaxial tensile properties (DIN 10555–3) of in vivo used catheters prove inferior to unused catheters. Material and methods5 unused, originally packed silicone catheters were cut into 6 segments of 50 mm: 3 segments each were cleaned via cleaning solution (n = 15) while 3 segments were left unattended (n = 15). Distal segments (50 mm) of long-term in vivo used silicone catheters were cleaned before testing (n = 33). Overall mechanical behavior was tested in a custom-made self-centering, torsion free carrier. Maximum force stress at failure, strain at failure and Young's modulus were determined and statistically analyzed. FindingsUnused catheters showed no significant difference in testing. in vivo used catheters exhibited 20% lower maximal force than unused catheters (p < 0.001), strain at break (p 〈0,001), and 7% higher elastic modulus (p = 0.004; power: 0.845). Due to a constant cross section area, stress at failure was proportional to maximum force (p < 0.001). Relation between determined parameters and dwell times was non-significant. InterpretationIn vivo long-term used silicone catheters showed significantly lower ultimate strength than unused ones. It is likely that in situ altering changes the mechanical properties of catheters and may potentially lead to failure.

Trees Adjust the Shape of Branch Unions to Increase Their Load-Bearing Capacity

The likelihood of branch union failure often needs to be assessed in tree risk assessment. Most of the guidance used in practice is based on the shape of these forks, specifically the shape (“U” or “V”), the angle between the branches, the presence of lateral bulges, and the aspect ratio of the branches. This study extends previous studies with a novel approach to the biomechanical analysis of fork shape and contributes results from destructive tests on two important European tree species, using comparatively large trees. Surprisingly, many samples deviated from the expected pattern of constant or decreasing cross-sectional area from the trunk beyond the fork. The results show three mechanisms that counteract the potential weakening at a bifurcation, two of which have not been documented before: an increase in section modulus from the stem base to where the stems part, an increase in section modulus caused by lateral bulging, and an increase in section modulus in the branches caused by an adjusted shape. Neither the shape of the forks nor the amount of included bark had a significant impact on their strength. Like several previous studies, the results of this study caution against the use of simple rules to assess the likelihood of branch union failure. The increasing availability of “digital twins” of urban trees may help us to use these results to assess the shape of branch unions in a quantitative way.

Air Flow Analysis for Protective Clothing Ventilation Elements with and Without Constant Cross-Section Area Opening

Abstract In this paper a ventilation element is designed with the constant cross-sectional area of 3.14 mm2 with the outer ring, to study the efficiency of ventilation at three different inlet air velocities (2, 5 and 8 m/s). There are five different cases analysed in the study, in which four cases are with different coordinate values of outer ring and core while the fifth case is studied with ventilation element without outer ring. The results of all five cases are analysed and compared to see the efficiency of ventilation element design. These ventilation elements are attached at ventilation hole at the inner part of the protective jacket. The attached ventilation element increases mechanical strength of the clothing by covering ventilation hole and restricting direct access of insects to the body. Moreover, ventilation elements permit smooth flow of air inside jacket. The objective is to determine which element’s geometrical configuration results in the minimum flow energy losses in the cell flow channel from the inlet to the outlet, which are represented by the pressure difference. Flow energy losses increase with increasing pressure difference (ΔP), and the body cooling reduces if the flow is weakened or there is of lost energy. SolidWorks Flow Simulation is used to calculate the pressure, temperature, and heat flux for the simplified elliptical model of the human body with a protective jacket. The obtained results are compared and analysed to study the concept of constant cross-sectional area in the design of ventilation elements with and without outer ring. The pressure and temperature difference for each case are calculated for the comparison and the obtained results show that the element design without outer ring provides better overall results and less flow energy loss in the cell flow channel than that of element design with outer ring.

Heat addition with variable area: Methodology for preliminary design of the scramjet combustion chamber

Well-known analytical approaches are commonly adopted for the preliminary design of scramjet engines. In this context, the combustion process in the combustion chamber can be modeled by considering heat addition to the airflow at supersonic speed. The one-dimensional Rayleigh flow theory can be applied to estimate the behavior of thermodynamic properties and velocities when the combustion chamber has a constant cross-sectional area and no mass is added within the duct. However, the temperature and pressure predicted by using constant area combustion chambers are too high, implying the necessity of modifications in the cross-sectional area of the chamber to avoid thermal choking and excessive pressure gradients. In this case, the unidimensional Rayleigh theory does not fit anymore. This work proposes an analytical methodology to estimate the airflow thermodynamic properties and velocities for scramjet combustion chambers with cross sections of variable areas by using an iterative algorithm that employs the Rayleigh flow area ratio theory. The analytical results were compared with the two-dimensional computational fluid dynamics analysis using the Reynolds-averaged Navier–Stokes method for both inviscid and viscous flow and considering turbulence effects. The proposed analytical model to estimate the flow behavior in the scramjet combustion chamber predicted results in agreement with the physics of the problem and with the results obtained via numerical simulation. The analytical model cannot predict oscillations in the flow properties caused by the expansion waves and their reflections. Still, the behavior and intensity of the properties are well captured along the entire length of three combustion chambers with variable area. The proposed algorithm is also applied to determine the angle of the combustion chamber that allows guaranteeing a constant, or a quasi-constant, static pressure along the length of the combustion chamber, approaching better the ideal thermodynamic Brayton cycle. The proposed model is suitable for preliminary scramjet designs and can be used to solve other problems involving variable area ducts.

Constructal Optimizations of Liquid-Cooled Channels with Triangle or Square Sections in a Cylindrical Heating Body

Two new integrated models with heat source–heat sink are established, in which isothermal liquid cooling channels with triangle or square sections are, respectively, embedded in a cylindrical heating body with uniform heat production. Based on constructal theory, under the conditions of a fixed cylinder cross-sectional area and the proportion of channels, taking the dimensionless maximum temperature and the dimensionless entransy equivalent thermal resistance (EETR) as the optimization goals, the influences of distribution of liquid cooling channels on the heat dissipation capacity of integrated models are studied with the number and the center distance of liquid cooling channels as design variables, and the optimal constructs with different proportions of channels are obtained. The results show that when the proportion of channels, cross-sectional area and the number of liquid cooling channels are given, there is an optimal center distance to make the overall heat dissipation performance of the integrated model reach its best, but the optimal center distances for the two indicators are different. The dimensionless maximum temperature and the dimensionless EETR decrease when the proportion of channels increases, but the optimal dimensionless center distances are almost the same for different proportions of channels. The dimensionless maximum temperature with the triangular cross-section is lower than that with the square cross-section under the conditions of constant cross-sectional area and dimensionless center distance, which is the same as the case for the dimensionless EETR. The results can furnish the theoretical guidelines for the thermal design of cylindrical devices needing efficient cooling.

A novel design method to produce 3D auxetic metamaterials with continuous pores exemplified through 3D rotating auxetic systems

Prototyping of three-dimensional mechanical metamaterials that exhibit negative Poisson’s ratio is usually performed through additive manufacturing. Although this technique has a huge potential, its use to engineer mechanical metamaterials for consumer products is still challenging. In this work, a novel design method is being proposed where 3D auxetic metamaterials can be produced by introducing continuous voids of constant cross-sectional area. Such voids would be inserted at strategic positions in different perpendicular planes of a solid block to obtain a continuous three-dimensional mechanical metamaterial that can exhibit the desired mechanical characteristics. The use of continuous voids to design the 3D meatamaterial makes it possible to use additive manufacturing, subtractive manufacturing as well as casting to produce these systems. The proposed design method is explained by using continuous voids having a diamond shaped cross-sectional area. The resulting group of structures can be described as connected polygons and were found to exhibit a negative or zero Poisson’s ratio. The analysed systems were also found to have a strain independent Poisson’s ratio up to at least 7% strain. The proposed design method can thus facilitate the availability of three dimensional auxetic metamaterials in the consumer market which to date is conspicuous by their absence.