Light weighting opportunities and material choice for commercial vehicle frame structures from a design point of view

This paper focuses on an estimation of light weighting opportunities for the frame structure of com- mercial road vehicles. This estimation is based on simpli- fied static load cases which play a predominant role for the dimensioning of a frame structure and therefore these simplifications are not putting the general validity of the conclusions into question. A comparison of different ma- terials under this scenario shows that light metals do not show any weight reduction advantage in comparison to steel while a material-independent topology optimization has more weight reduction potential for the frame structure than a simple change of materials. Considering the con- straints of part complexity which is directly linked with production and assembly cost, the ladder frame structure has become the current state of the art design. Thus the paper also puts a spotlight on basic rules of node design and vertical load induction in order to keep the weight of such a design as low as possible. Practical examples from manufacturers show that the weight of a commercial vehicle could be reduced by 10%, and main parts of the frame structure could be reduced by 30% using high strength steel in combination with innovative production methods like roll forming.

Influence of expanded polystyrene size on deformation characteristics of light weight soil

Deformation characteristics of light weight soil with different EPS (expanded polystyrene) sizes were investigated by consolidation tests.The results show that the confined stress-strain relation curve is in S shape,which has a good homologous relation with e-p curve and e-lgp curve,and three types of curves reflect obvious structural characteristics of light weight soil.When cement mixed ratio and EPS volume ratio are the same for different specimens,structural strength decreases with the increase of EPS size,but compressibility indexes basically keep unchanged within the structural strength.The settlement of light weight soil can be divided into instantaneous settlement and primary consolidation settlement.It has no obvious rheology property,and 90% of total consolidation deformation can be finished in 1 min.Settlement-time relation of light weight soil can be predicted by the hyperbolic model.S-lgt curve of light weight soil is not in anti-S shape.It is proved that there is no secondary consolidation section,so consolidation coefficient cannot be obtained by time logarithm method.Structural strength and unit price decrease with the increase of EPS size,but the reducing rate of the structural strength is lower than that of the unit price,so the cost of mixed soil can be reduced by increasing the EPS size.The EPS beads with 3-5 mm in diameter are suggested to be used in the construction process,and the prescription of mixed soil can be optimized.

Light-Weight Design Method for Force-Performance-Structure of Complex Structural Part Based Co-operative Optimization

A light?weight design method of integrated structural topology and size co?optimization for the force?performance?structure of complex structural parts is presented in this paper. Firstly, the supporting function of a complex structural part is built to map the force transmission, where the force exerted areas and constraints are considered as connecting structure and the structural configuration, to determine the part performance as well as the force routines. Then the connecting structure design model, aiming to optimize the static and dynamic performances on connection configuration, is developed, and the optimum design of the characteristic parameters is carried out by means of the collaborative optimization method, namely, the integrated structural topology optimization and size optimization. In this design model, the objective is to maximize the connecting stiffness. Based on the relationship between the force and the structural configuration of a part, the optimal force transmission routine that can meet the performance requirements is obtained using the structural topology optimization technology. Accordingly, the light?weight design of conceptual configuration for complex parts under multi?objective and multi?condition can be realized. Finally, based on the proposed collaborative optimization design method, the optimal performance and optimal structure of the complex parts with light weight are realized, and the reasonable structural unit configuration and size charac?teristic parameters are obtained. A bed structure of gantry?type machining center is designed by using the proposed light?weight structure design method in this paper, as an illustrative example. The bed after the design optimization is lighter 8% than original one, and the rail deformation is reduced by 5%. Moreover, the lightweight design of the bed is achieved with enhanced performance to show the effectiveness of the proposed method.

Light weight analysis of a skeleton vehicle frame using BS960 super-high-strength steel

Static strength finite element analysis was conducted to decrease the weight of a skeleton vehicle＇s frame. Results indicated that the maximum stress occurs on the front beam ＇s variable section area. Dynamic sensitivity analysis elucidated the relationship between the maximum stress and the thickness of a particular beam,e. g.,top,middle,and bottom beam. Displacement was analyzed by the key part that influenced the maximum stress. Finally,the new plan using BS960 super-high-strength beam steel and the preferred beam thickness was compared with the original plan. New combinations of beam thickness were introduced on the basis of different purposes; the maximum responding light w eight ratio was 21%.

Neuro-fuzzy systems in determining light weight concrete strength

The adaptive neuro-fuzzy inference systems(ANFIS)are widely used in the concrete technology.In this research,the compressive strength of light weight concrete was determined.To this end,the scoria percentage and curing day variables were used as the input parameters,and compressive strength and tensile strength were used as the output parameters.In addition,100 patterns were used,70%of which were used for training and 30%were used for testing.To assess the precision of the neuro-fuzzy system,it was compared using two linear regression models.The comparisons were carried out in the training and testing phases.Research results revealed that the neuro-fuzzy systems model offers more potential,flexibility,and precision than the statistical models.

Development of Light Weight Structures to Provide Blast-Resistant Designs

In the past, blast-resistant designs for structures were often constructed with massive type structural systems, which relied more on brute strength than on finesse to achieve the required blast resistance. However, structures composed of COLD-FORMED steel components, such as sheet metal and metal studs, have shown great promise in providing blast resistance with the added benefits of low cost and ease of construction. Some examples of using such structures to provide containment for package handling facilities (PHF) are described in the paper for situations where blast containment is needed, such as a potential package bomb being discovered during the package vetting process. Results from tests and analytic data are used to illustrate aspects of design peculiar to such types of applications. Designs for specific capacities of PHF are described.

Bond Strength of Bamboo Reinforcement in Light Weight Concrete

Bamboo reinforced concrete as a building material is expected to be an alternative to steel reinforced concrete. Due to the fact that steel is not renewable and polluting steel mills are fairly high. The bond strength is a major concern for the natural fiber used as reinforcement in structural composites. This paper reports study on the bond strength of bamboo reinforcement in concrete, to determine the adhesion reinforcement in concrete often do by the pull-out test. The research objective was bond strength of lightweight concrete and bamboo reinforcement. The test used light weight concrete with foam additives klerak. Bamboo slats were coated with paint and sprinkled with sand. The results obtained showed that the bond strength bamboo 60% of the bond strength steel.

Recent development in aluminium for automotive applications

Aspects of material selection and innovative concepts of car construction using aluminium as best suited light-weight materials were presented, and recent development in established and advanced use of aluminium in passenger cars was discussed that help to meet economic and environmental requirements. 5xxx and 6xxx aluminium alloys were presented that have been improved for the increasing demands regarding higher strength and better formability, resulting in a mass reduction and improved crashworthiness. Furthermore, advances concerning multi-material light weight design were presented by examples for aluminium solutions in advanced “Multi-material” Super-Light-Car （SLC） concepts, which reaches significant mass reductions.

Magnesium based surface metal matrix composites by friction stir processing

Surface metal matrix composites(MMCs)are a group of modern engineered materials where the surface of the material is modified by dispersing secondary phase in the form of particles or fibers and the core of the material experience no change in chemical composition and structure.The potential applications of the surface MMCs can be found in automotive,aerospace,biomedical and power industries.Recently,friction stir processing(FSP)technique has been gaining wide popularity in producing surface composites in solid state itself.Magnesium and its alloys being difficult to process metals also have been successfully processed by FSP to fabricate surface MMCs.The aim of the present paper is to provide a comprehensive summary of state-of-the-art in fabricating magnesium based composites by FSP.Influence of the secondary phase particles and grain refinement resulted from FSP on the properties of these composites is also discussed.

Microstructure and mechanical properties of dissimilar steel plate resistance plug welding joints

A new type of hybrid welding method called resistance plug welding （RPW） was firstly adopted to achieve the connecting of dissimilar steel, mainly as for the poor welding characteristics of high strength steel produced by increasing carbon, manganese, silicon, etc. Microstructures and mechanical properties of RPW joint were analyzed by optical microscope,micro-hardness test and shear tensile measurement. Experimental results indicate that the RPW joint has a rounded rectangle nugget ^ and the size is larger than elliptical nugget of resistance spot welding （RSW） jo in t; the hardness value of RPW joint is evenly distributed, accordingly there is no hard brittle phases ; the shear tensile strength o f RPW joint increases by 20% in comparison with RSW joint under the same welding conditions.

Improved High Speed Flame Detection Method Based on YOLOv7

In order to solve the problems of the traditional flame detection method, such as low detection accuracy, slow detection speed and lack of real-time detection ability. An improved high speed flame detection method based on YOLOv7 is proposed. Based on YOLOv7 and combined with ConvNeXtBlock, CN-B network module was constructed, and YOLOv7-CN-B flame detection method was proposed. Compared with the YOLOv7 method, this flame detection method is lighter and has stronger flame feature extraction ability. 2059 open flame data sets labeled with single flame categories were used to avoid the enhancement effect brought by high-quality data sets, so that the comparative experimental effect completely depended on the performance of the flame detection method itself. The results show that the accuracy of YOLOv7-CN-B method is improved by 5% and mAP is improved by 2.1% compared with YOLOv7 method. The detection speed reached 149.25 FPS, and the single detection speed reached 11.9 ms. The experimental results show that the YOLOv7-CN-B method has better performance than the mainstream algorithm.

A Study on Hovering Control of Small Aerial Robot by Sensing Existing Floor Features

Since precise self-position estimation is required for autonomous flight of aerial robots, there has been some studies on self-position estimation of indoor aerial robots. In this study, we tackle the self-position estimation problem by mounting a small downward-facing camera on the chassis of an aerial robot. We obtain robot position by sensing the features on the indoor floor.In this work, we used the vertex points(tile corners) where four tiles on a typical tiled floor connected, as an existing feature of the floor. Furthermore, a small lightweight microcontroller is mounted on the robot to perform image processing for the onboard camera. A lightweight image processing algorithm is developed. So, the real-time image processing could be performed by the microcontroller alone which leads to conduct on-board real time tile corner detection. Furthermore, same microcontroller performs control value calculation for flight commanding. The flight commands are implemented based on the detected tile corner information. The above mentioned all devices are mounted on an actual machine, and the effectiveness of the system was investigated.

Size effect of lattice material and minimum weight design

The size effects of microstructure of lattice materials on structural analysis and minimum weight design are studied with extented multiscale finite element method（EMsFEM） in the paper. With the same volume of base material and configuration, the structural displacement and maximum axial stress of micro-rod of lattice structures with different sizes of microstructure are analyzed and compared.It is pointed out that different from the traditional mathematical homogenization method, EMsFEM is suitable for analyzing the structures which is constituted with lattice materials and composed of quantities of finite-sized micro-rods.The minimum weight design of structures composed of lattice material is studied with downscaling calculation of EMsFEM under stress constraints of micro-rods. The optimal design results show that the weight of the structure increases with the decrease of the size of basic sub-unit cells. The paper presents a new approach for analysis and optimization of lattice materials in complex engineering constructions.

Light-weight refractory high-entropy alloys: A comprehensive review

In recent years,high-entropy alloys(HEAs)have become a research hotspot in materials community,and great progress has been made in exploring various high-performance HEAs.As a special class,the light-weight refractory high-entropy alloys(RHEAs)own both excellent high-temperature comprehensive properties and low density and have accordingly attracted more and more attention.In this paper,we presented a comprehensive review of the recent progress and status in light-weight RHEAs.Based on an exhausting search of the literature reports,one strategy in terms of phase numbers after preparation was first proposed to classify the light-weight RHEAs into three categories.Then,the status on the fundamental thermodynamic and thermophysical data/databases,computational approaches for alloy designing,and preparation/fabrication techniques of light-weight RHEAs was introduced one after another.After that,the progress on mechanical properties and oxidation/corrosion/wear behaviors of light-weight RHEAs at room and high temperatures was summarized.Finally,the conclusions of this review were drawn.By pointing out the shortcomings of the current research,the follow-up development directions in the field of light-weight RHEAs were also given.

Carbon Emission Cycle and Literature Measurement of Carbon Fiber Vehicles

Carbon fiber is a kind of high-temperature fiber with high modulus and strength characteristics.Carbon fiber material is made of carbon fiber braid with carbon content>90%.Among them,resin-based carbon fiber reinforced composite material is often used as automotive structural material.Compared with the A36 steel commonly used in automobiles,the T300/5208 carbon fiber reinforced epoxy resin composite commonly used in automobiles has a higher tensile strength of 2500-3300 MPa and a lower density of 6.25 g/cm 3,showing great performance advantages.In this paper,by analyzing the trend of automobile lightweight,and exploring the development prospects of carbon fiber in the field of automobile lightweight,the literature in the Elsevier database is analyzed by scientific measurement analysis method,and the research hotspot in the field is listed.The relationship between the development of fiber materials and the promotion of policies is analyzed by comparing the number of carbon fiber automobile literature publications and key event nodes.This paper proposes a keyword-based influence calculation method.Through drawing analysis tools of information visualization scientific knowledge map and scientific measurement methods of keyword,it proposes the scientific measurement analysis literature of on-board carbon fiber,explores and discusses some frontier directions of automotive carbon fiber materials.The research provides reference for studying automobile lightweight carbon fiber material.

Buoycrete and Membrane Molding

In this study,the authors present Buoycrete,a new material and work method invented by the company Boskalis.Buoycrete is a light-weight concrete that is able to float and does not dissolve in water.Buoycrete is based on a unique combination of different materials.This paper will start with an overview of concrete structures in combination with fabrics and will present the structural behavior,construction methods and applications of Buoycrete.It demonstrates that Buoycrete combined with fabric formwork creates new possibilities for a broad kind of applications,for instance,the realization of façade elements,shell structures and civil engineering.

Experimental-mechanistic analysis of pavement base deflections measured with light weight deflectometer

An extensive experimental-mechanistic study was conducted to reveal the relationship between the light weight deflectometer(LWD)measured deflections and the degree of compaction of pavement base materials.Both laboratory experiments and test pits experiments were performed with different types of pavement base materials.The modulus based maximum allowable LWD deflections under different structural and compaction conditions were developed for the most commonly used pavement base aggregate in Indiana.The maximum allowable deflections are based on the equivalent subgrade modulus and the thickness of the layer to be compacted.It is emphasized that the LWD deflections must be measured as soon as the material is compacted or before the moisture content decreases beyond a specified range.Therefore,the maximum allowable deflections are specified in terms of the difference between the actual moisture content and the optimum moisture content.The maximum allowable deflection values provide a sound basis for compaction quality control using LWD devices.

Biomimetic porous silicon oxycarbide ceramics with improved specific strength and efficient thermal insulation

Considering the challenge of aerodynamic heating,the development of high-performance insulating ce-ramic materials with lightweight and low thermal conductivity is crucially important for aerospace vehi-cles to achieve flight at high speed for a long time.In this work,macro-porous silicon oxycarbide(SiOC)ceramics with directional pores(DP-SiOC)(mean pore size of 88.1μm)were prepared using polysiloxane precursors via freeze casting and photocrosslinking,followed by pyrolysis.The DP-SiOC samples were lightweight(density∼0.135 g cm^(-3))with a porosity of 90.4%,which showed good shapability through the molding of polysiloxane precursors.The DP-SiOC samples also exhibited an ultra-low thermal con-ductivity of 0.048 W(m K)^(-1)at room temperature,which can also withstand heat treatment at 1200°C for 1 h.In addition,scaffolds with triply periodic minimal surfaces(TPMS)were fabricated using digital light processing(DLP)printing,which was further filled with polysiloxane precursors for increasing the strength of DP-SiOC.The TPMS scaffolds filled with macro-porous SiOC ceramics(TPMS-DP-SiOC)showed good integration between TPMS and macro-pore structures,which had a porosity∼75%and high specific strength of 9.73×10^(3)N m kg^(-1).The thermal conductivity of TPMS-DP-SiOC samples was 0.255 W(m K)^(-1)at room temperature.The biomimetic TPMS-DP-SiOC ceramics developed in this study are likely used for thermal protection systems.

A light-weight high-entropy alloy Al_(20)Be_(20)Fe_(10)Si_(15)Ti_(35)

A light-weight high-entropy alloy （LWHEA） A120Be20Fe10SilsTi35 has been developed to have unique mechanical properties and oxidation resistance. One major and two minor phases are observed in the as-east microstructure. The density of the alloy is 3.91 gcm-3, and its hardness is HV 911, which is higher than quartz. The hardness and hardness to density ratio are the highest of all light-weight alloys reported before. In addition, it has excellent oxidation resistance at 700℃ and 900℃, which far exceeds that of Ti-6A1-4V. Thus, the combination of properties is promising for high-temperature applications, which require light weight, wear-resistant and oxidation-resistant components.

Carbonized wood with ordered channels decorated by NiCo_(2)O_(4) for lightweight and high-performance microwave absorber

Wood-derived carbon has a 3D porous framework composed of through channels along the growth direction,which is a suitable matrix for preparing electromagnetic wave(EMW)absorbing materials with low cost,light weight,and environmental friendliness.Herein,the carbonized wood decorated by short cone-like NiCo_(2)O_(4)(NiCo_(2)O_(4)@CW)with highly ordered straight-channel architecture was successfully manufactured through a facile calcination procedure.The horizontal arrangement of the through channels of NiCo_(2)O_(4)@CW(H-NiCo_(2)O_(4)@CW)exhibits a strong reflection loss value of-64.0 dB at 10.72 GHz with a thickness of 3.62 mm and a low filling ratio of 26 wt%(with the density of 0.98 g-cnf3),and the effective absorption bandwidth(EAB)is 8.08 GHz(9.92-18.0 GHz)at the thickness of 3.2 mm.The excellent microwave absorption(MA)property was ascribed to the ordered-channel structure with abundant interfaces and defects from NiCo_(2)O_(4)@CW,which could promote the interfacial polarization and dipole polarization.What is more,this advantageous structure increased the multiple reflections and scattering.Finite element analysis(FEA)simulation is carried out to detect the interaction between the prepared material and EMW when the ordered channels are arranged in different directions.This research provides a low-cost,sustainable,and environmentally friendly strategy for using carbonized wood to fabricate microwave absorbers with strong attenuation capabilities and light weight.