Hou Liang

• Doctor of Engineering
• Professor at Xiamen University

Optimizing superplastic forming (SPF) process parameters is vital for improving production efficiency and addressing the growing complexity of product requirements in high-end manufacturing fields. Current optimization of SPF process parameters focuses on meeting product requirements, often overlooking constraints related to quality indicators, pro...

The accumulation of plastic strain resulting from repeated thermal cycling can lead to residual deformation that seriously impacts the forming quality of functionally gradient materials (FGMs) during laser directional energy deposition (L-DED) processing. The accumulated plastic strain in L-DED depends mainly on the high-temperature constitutive be...

Laser directed energy deposition (LDED) offers great potential for fabricating dual nickel-based alloy blisks, due to its capability for in-suit alloying and creating graded powder-ratio zones to join dissimilar materials. However, blisk blades, which demand high-temperature durability, typically utilise γ'-strengthened nickel-based alloys, such as...

Turbine blisk used for aerospace engines withstands harsh working environments and requires multiple materials suited for different function requirements. Laser-directed energy deposition (L-DED) is ideal for manufacturing of multi-material turbine blisk. This study investigates the L-DED manufacturability of two dissimilar nickel-based superalloys...

The active safety system of a vehicle typically relies on real-time monitoring of the sideslip angle and other critical signals, such as the yaw rate. The vehicle sideslip angle cannot be measured directly due to the high cost and impracticality of sensor networks. The vehicle sideslip can be estimated using kinematic, dynamic, or machine-learning...

This study presents an error flow research method for simulation models of hydraulic systems in construction machinery based on the state-space approach, aiming to ensure the reliable application of digital twin models. Initially, a comprehensive analysis of errors in the simulation modeling of hydraulic systems in construction machinery was conduc...

Fast and accurate measurement of the volume of earthmoving materials is of great significance for the real-time evaluation of loader operation efficiency and the realization of autonomous operation. Existing methods for volume measurement, such as total station-based methods, cannot measure the volume in real time, while the bucket-based method als...

Due to the fact that rotors usually operate in a non-stationary mode with changing speeds, the conventional rotor unbalance detection method based on the stationary signal will produce a major “spectrum ambiguity issue” and affect the accuracy of rotor unbalance detection. To this end, a tacholess order tracking method based on the STFTSC algorithm...

The near-beta titanium alloy Ti5333 with high strength is difficult to cut, and accurate FE simulation models are needed to assess its machinability. This work compares for the practical turning process of the performances of two material plastic models, i.e., the Johnson–Cook model without strain softening and the TANH model with strain softening....

Predictive milling distortion has been widely used to optimize milling design and process. Inherent strains method (ISM) applies plastic strains calculated from small-scale thermo-mechanical simulations to large-scale models to assess residual deformation in less time. In this paper, ISM is proved feasible in milling process by theoretical and expe...

The dual oil circuit centrifugal fuel nozzle is made of martensitic stainless steel, which has complex morphological characteristics. The surface roughness characteristics of the fuel nozzle directly affect the degree of fuel atomization and the spray cone angle. The surface characterization of the fuel nozzle is investigated by the fractal analysi...

Large thermal distortions due to the cyclic rapid melting and solidification mechanism in metal additive manufacturing (MAM) affect part manufacturing precision. The so-called inherent strain method is one of the most computationally efficient methods to predict distortion, but the current inherent strain methods extract inherent strains through th...

Operating data-driven inverse design (DID) provides updated knowledge for the forward design process. It forms a closed-loop of design enhancements in which uncertainties from different sources, such as the model and environment, have a significant impact on the design and optimisation results. This paper proposes a method for analysing DID uncerta...

In engineering practice, the bus powertrain mounting system (BPMS) may have both epistemic and aleatory uncertainty under the influence of manufacturing, measurement, and assembly errors. The hybrid uncertainty in BPMS may result in over-design or insufficient design. Therefore, the probability box (p-box) model, which can handle both aleatory and...

The accurate estimation of parameters is the premise for establishing a high-fidelity simulation model of a valve-controlled cylinder system. Although bench test data are convenient to obtain in model parameter estimation, there is a need for the load data to conform to the actual working conditions. Although the operating data include the actual l...

Fast and accurate measurement of the volume of earthmoving materials is of great significance for the real-time evaluation of loader operation efficiency and the realization of autonomous operation. Existing methods for volume measurement, such as total station-based methods, cannot measure the volume in real time, while the bucket-based method als...

Identifying risky components is crucial to improving product reliability in the final redesign of products. Design failure mode and effects analysis has become a prevalent application in product redesign as a useful risk assessment method. However, critical data, which contain failure causality relationships (FCRs) between failure modes, correlatio...

A few design schemes can be derived using the modularisation strategy, which can effectively reduce the assembling cost and delivery time to the development of product design. Therefore, it is important to select modular architecture design schemes (MADSs) according to evaluation information (fuzzy and uncertain) provided by design experts. As a cl...

To handle the problem of low detection accuracy and missed detection caused by dense detection objects, overlapping, and occlusions in the scenario of complex construction machinery swarm operations, this paper proposes a multi-object detection method based on the improved YOLOv4 model. Firstly, the K-means algorithm is used to initialize the ancho...

The bucket fill factor is a core evaluation indicator for the optimization of the loader’s autonomous shoveling operation. Accurately predicting the bucket fill factor of the loader after different excavation trajectories is fundamental for optimizing the loader’s efficiency and energy cost. Therefore, this paper proposes a method for predicting th...

With the maturity of sensor and data acquisition technology, the intelligent development of multi-sensor integrated loader becomes inevitable. This paper focuses on the realization of intelligent recognition of loader's working stage via low-cost and efficient sensor configuration of bulk operation data. A feature selection method, Redundancy-Compl...

Complex free-form parts manufactured by directed energy deposition (DED) have problems of uneven allowance distributions and severe stair-case effects. In order to optimize allowance for post-machining in a hybrid additive and subtractive machine centre, a point cloud registration method is proposed for allowance optimization to match the on-machin...

To overcome the difficulty of collecting the working resistance and working trajectory of a wheel loader, this paper constructs a statics model of the bucket working resistance and a kinematics model of the working trajectory in the shoveling process and analyzes the key parameters of measuring the working resistance and working trajectory. Based o...

Saturated highlights on metal surfaces reduce the detection accuracy of fuel nozzles. In this paper, we propose an image inpainting method with a saturated highlight based on the statistics of similar patches used in prior segmentation of the subregion. The sequence image acquisition is based on the shape from focus in the five-axis platform. By ou...

Accurate energy flow results are the premise of excavator energy-saving control research. Only through an accurate energy flow analysis based on operating data can a practical excavator energy-saving control scheme be proposed. In order to obtain the excavator’s accurate energy flow, the excavator components’ performance and operating data requirem...

Design experts need to fully understand the failure risk of a product to improve its quality and reliability. However, design experts have different understandings of and concepts in the risk evaluation process, which will lead to cognitive asymmetry in the product’s redesign. This phenomenon of cognitive asymmetry prevents experts from improving t...

In this paper, an instantaneous frequency identification method known as STFTSC is developed by combining short-time Fourier transformation and the seam carving (SC) algorithm (widely used in image processing). In this method, the STFT is applied to analyze the time-frequency energy distribution of a vibration signal under variable-speed conditions...

An accurate thermal simulation of direct laser deposition (DLD) provides a basis for optimizing DLD process parameters. However, the input thermal parameters that significantly affect the simulation performance are difficult to be measured directly through experimental methods. This paper proposes an inverse method to identify the heat source param...

Thermal-mechanical simulation of direct energy deposition (DED) is an effective method to predict the residual stress and deformation and optimize deposition process parameters. The simulation accuracy depends on input parameters which are difficult to be directly and accurately measured in most cases. This paper, taking heat source parameters as e...

Chatter in machining results in poor workpiece surface quality and short tool life. An accurate and reliable chatter detection method is needed before its complete development. This paper applies a novel p-leader multifractal formalism for chatter detection in milling processes. This novel formalism can discover internal singularities rising on uns...

Balancing and sequencing are two important problems in paced assembly lines planning. Many studies use a precedence graph to solve the problems. Fixed takt time (fTT) is used as the paced value of assembly lines, which ignores the real-time status of assembly lines. By analyzing the position of each product on the assembly lines and the working tim...

A dynamic model with four masses and 19 degree of freedoms is proposed to investigate the vibration response characteristics of an axial piston pump. In the model, main parts are simplified by multiple lumped mass points connected with spring-damper elements. Experimental investigation is performed, and the discharge dynamic pressures and vibration...

Traditional design requires designers to envisage a product operating environment in order to identify customer needs. Analyzing product usage context by collecting actual product operating data during the product in use empowers new opportunities for the projection of requirement specifications and understanding of use case scenarios. This paper p...

Chatter is a major limitation in the machining process, which affects the machined surface and productivity. An accurate stability lobes diagram is efficient to avoid chatter. A small radial depth of cut often used in finish milling means a small uncut chip thickness and highly interrupted machining process. The tool is easy to jump out from the wo...

In this paper, based on the subjective evaluation results of 50 noise samples from different forklifts using the rank score comparison (RSC), a subjective fuzzy comprehensive evaluation method of forklift sound quality was presented. With partly reference to the radiated noise test standard, five measuring points and two steady-state working condit...

A novel porous copper fiber sintered sheets (PCFSSs) with different porosities were fabricated using the cutting copper fibers with rough surface. The effect of fiber surface morphology, porosity, thickness and gradient pore structure of PCFSS on sound absorption performance was tested by using the transfer function method. Our results show that th...

Articulated steering vehicles have outstanding capability operating but suffer from frequent rollover accidents due to their complicated structure. It is necessary to accurately detect their rollover risk for drivers to take action in time. Their variable structure and the variable center of mass exhibit nonlinear time-variant behavior and increase...

Bearing capacity of the unstructured terrain considering the effects of the wheel geometry and soil mechanic properties is analyzed in this paper. Two-dimensional pressure-sinkage simulations are conducted to evaluate the degrees of similarity between the flat plate and wheel in terms of their ultimate bearing characteristics of Terzaghi theory. Th...

The demands on improving the noise, vibration and harshness of passenger vehicles are growing rapidly. Low-frequency vibration of steering wheel is one of the most important factors leading to the discomfort of drivers. This study proposes a systematic analysis methodology to reduce the low-frequency vibration of steering wheel using classical tran...

Chatter is a self-excited vibration that affects the part quality and tool life in the machining process. This paper introduces an intelligent chatter detection method based on image features and the support vector machine. In order to reduce the background noise and highlight chatter characteristics, the average FFT is applied to identify the domi...

Chatter is a cause of low surface quality and productivity in milling and crucial features need to be extracted for accurate chatter detection and suppression. This paper introduces a novel feature extraction approach for chatter detection by using image analysis of dominant frequency bands from the short-time Fourier transform (STFT) spectrograms....

Bonnet polishing technology has been widely applied in precision optical machining. Until now, most of the research concerning the modeling for material removal mechanisms of bonnet polishing have been presented based on the well-known Preston model. However, the various parameters involved in the bonnet polishing process are not formulated into th...

Aiming at the common problems of the engineering vehicles with high environment noise and poor acoustic comfort, this paper proposes an acoustic comfort subjective evaluation method based on rank score comparison (RSC) and develops a corresponding software system; it provides the solution method of evaluation modeling and improvement measure based...

Chatter detection in metal machining is important to ensure good surface quality and avoid damage to the machine tool and workpiece. This paper presents an intelligent chatter detection method in a multi-channel monitoring system comprising vibration signals in three orthogonal directions. The method comprises three main steps: signal processing, f...

There have been many researches concerning the modeling for material removal mechanisms of bonnet polishing (BP) based on the well-known Preston model. However, various parameters involved in the BP process are not formulated and considered in the classical model, such as slurry characteristics, pad properties, bonnet features, and processing condi...

This paper extends the topology optimization (TO) methods of fluid flows to design the three-phase (i.e. solid, fluid and porous materials) interpolation scheme. In addition to numerous studies about the optimized layout of regions governed by Darcy-Stokes equations, this paper aims to minimize the pressure attenuation in multiple phase interpolati...

The evaluation of the difficulty level of operating conditions is one of the key problems in intelligent management of the wheel loader engine power. This paper presents a method for evaluating the difficulty level of wheel loader operating conditions based on radar chart. Firstly, we analyze the characteristics of the wheel loader operation spectr...

This paper presents a method for fabricating a tri-dimensional reticulated porous material (TRPM) made of copper fibers and an experimental study of the acoustic performance of the TRPM. Continuous copper fibers are produced through a multi-tooth tool, and sintered using a low-temperature solid-phase sintering (LSS) technique to fabricate the TRPM....

In industrial application and teaching training, robot simulation plays an important role. In this paper, the method of system development is discussed. First the robot model and simulation scene model are built. And the kinematics model is established including positive and inverse kinematics. Then two kinds of path, line and circle, are planned a...

To deal with the issue of performance optimization and control in the gradual evolution process of modular product family for make-to-order enterprises, the neural network and configuration optimization techniques were utilized to realize performance maximization. Both abrupt change and gradual evolution in product family evolution process were ela...

Earthmoving equipment in motor graders, which can be considered to be complex multibody systems (MBSs), are critical components for earthwork, compaction and re-handling. They have not yet received much attention due to their unusual applications and complicated structures. In this paper, a comprehensive study of an earthmoving MBS, from the mechan...

A hydraulic excavator has a number of devices attached, the operating speeds of which are important performance indicators for performance evaluation and end-of-line inspection. This paper proposes an online and low-cost detection method to estimate the operating speed based on the peak detection of the main pump outlet pressure. A pressure sensor...

Accurately determining the unknown noise sources from a vehicle is critical to noise control; however, it is very difficult in the practical application and an efficient method for locating such noise sources is lacking. In this work, a method for noise sources determination is proposed based on a corrected fast independent component analysis (Fast...

The inlet grid and exhaust grid are widely used in engineering machinery products. The process that airflow goes through grids is a complex turbulent flow and directly related to the heat dispersion and aerodynamic noise. The theoretical analysis result shows that the jet noise generated by airflow has a connection with the grid structure form, flu...

To better solve the complex non-linear problem between the subjective sound quality evaluation results and objective psychoacoustics parameters, a method for the prediction of the sound quality is put forward by using a back propagation neural network (BPNN) based on particle swarm optimization (PSO), which is optimizing the initial weights and thr...

The noise signals from the engine compartment of a forklift are wideband non-stationary random signals as their structure and working process are complex. In order to separate and identify the noise sources of the engine compartment, blind source identification analysis was carried out based on fast independent component analysis (FastICA) algorith...

How to leverage the contradiction between commonality and diversity within a product family has been regarded as one of the crucial problems in Mass Customization. In order to support the process of product family design and optimization, a quantitative methodology for analyzing the relationship between feature commonality of generic components and...

Assembly line balancing not only directly determines production efficiency but also influences precision and quality of key assemblies or even the overall performance of final products. Driven by market demand and development of science and technology, product family must evolve constantly, which necessitates frequent adjustment and rebalancing of...

Additive manufacturing (AM) technology has the potential to significantly improve supply chain dynamics, reduce shipping costs and shorten delivery lead times. Using AM technology, manufacturers can produce parts on demand and thus reduce the need of maintaining safety inventory. This is especially useful in the aircraft spare parts industry where...

aiming at the difficulty of dynamic evaluation and realizing innovation in Product Family Evolution (PFE), an evaluation method of the product family for mass customization is presented by analyzing the influences of customer needs, enterprise resources and product data in the implementation process of Product Family (PF). From the perspective of t...

Commonality analysis is the starting point of product family redesign, providing guidance for enterprises to improve commonality, reduce product cost and manufacturing complexity. Firstly, the component-based commonality indices introduced so far are analyzed and the deficiency in respect to commonality evaluation of outsourced function module is i...

Product family assembly line (PFAL) is a mixed-model assembly line on which a family of similar products can be assembled at the same time. Aiming at the balance problem of PFAL, a balancing model for PFAL is established, and simultaneously an improved dual-population genetic algorithm is proposed. Firstly, through the characteristic analysis of PF...

A good cooling circle should ensure that the system can work at an appropriate temperature in the requirements of power increase, engine compartment constraint and working demands for modern engineering machinery, which asks for a thorough understanding of system thermal loads before practical production. However, traditional experiment method spen...

A micromixer is an important component of microfluidic systems, which reveals wide and essential applications in the field of chemistry and biochemistry. In the micro scale, diffusive mixing is notoriously slow as fluid is in the form of laminar flow. Therefore, design of a high performance micromixer to mix fluids at short distance is essential fo...

To overcome the difficulty of dynamic evaluation and driver analysis in product family evolution (PFE), a comprehensive evaluation approach was proposed by analyzing the influences of customer needs, enterprise resources, and product data in the product family implementation process. From the perspective of time and space, the dynamic and static re...

This paper proposes a method for the design of gear tooth profiles using parabolic curve as its line of action. A mathematical model, including the equation of the line of action, the equation of the tooth profile, and the equation of the conjugate tooth profile, is developed based on the meshing theory. The equation of undercutting condition is de...

Aiming at the module planning problem in product family design, the modular theory and implementation methods of core systems for product family were researched, and a variety of dynamic elements in product life cycle were analyzed. According to the influence of market factors' dynamic changes such as core system components on modular planning, a d...

This paper aims to propose a design method for tooth profiles of spur gears based on given line of action. A simplified derivation of the mathematical model of tooth profiles is introduced according to the meshing theory. Tooth profiles of spur gears, using a parabola as line of action, is established. The result shows that it will be better to con...

It is crucial to properly evaluate the running state of the product family for the enterprises to determine the direction of product family evolution and establish the management strategies of R&D-production-marketing. In order to effectively evaluate the running state of the complex product family system in dynamic evolution with uncertainty facto...

For effectively use patents as information resource for aiding product innovation and avoid patent infringement, a method using patent knowledge based on Design Structure Matrix (DSM) and Theory of Innovative Problem Solving (TRIZ) is proposed. First the couple relationship between different components in objective patent of product is analyzed by...

Thirty years into its development, additive manufacturing has become a mainstream manufacturing process. Additive manufacturing build up parts by adding materials one layer at a time based on a computerized 3D solid model. It does not require the use of fixtures, cutting tools, coolants, and other auxiliary resources. It allows design optimization...

According to the innovation of specific module during the process of product platform in innovation and evolution, a method of using patent knowledge for aiding modules innovation based on axiomatic design and TRIZ was put forward. Firstly, we design the model of innovative design of module based on patent. On this basis, we construct the process o...

In order to solve the problem of error and abstract in the identification process caused by current wavelet methods using grayscale to identify noise sources, a cabin noise source identification method based on wavelet transform(WT) was proposed. Firstly, multi-wavelet reconstruction signals were constructed from original time-domain signals throug...

By simplifying the triangular tracked engineer vehicle into dynamic model of half-tracked vehicle with five freedom degrees which includes four vertical jumps and one rotation, a corresponding dynamic differential equation is set up to each degree of freedom. A method of road roughness simulation, based on the time series of White Noise, is also re...

Aiming at selecting appropriate parts in the product family architecture for innovating, a method for part analysis and selection in the renewal process of product family architecture is initially proposed. On the basis of parts analysis from the three aspects of cost effectiveness-commonality, performance sensitivity and demand-matching degree, a...

This paper designed and developed an integrated testing system for performance parameters of the Hydraulic excavator. Combined with sensing technology, computer technology and virtual instrument technology this system can detect six key parameters of the excavator including motor speed, hydraulic system pressure, attachment action time, swing speed...

A new type of spherical gear drive, which takes micro-segment involute profile as tooth profile, is presented in this paper. The generation principle of the spherical gear is described. The mathematical models including the equation of micro-segment involute profile, the equation of the conjugate tooth profile and the engagement equation, are estab...

Aiming at the ability to adapt to different road conditions of limited-slip differential(LSD) in drive axle, by building the without preloading friction disk type limited slip differential mechanical model, We derive the theoretical formula of the locking differential coefficient of the theoretical formula of limited slip differential without prelo...